A couple has six children, all daughters. If the woman has a 7th child, what is the probability that the 7th child will be a daughter?
If genes R and S are on two different chromosomes and the probability of allele R segregating into a gamete is 1/4 while the probability of allele S segregating into a gamete is 1/2, what is the probability that both will segregate into the same gamete?
A) 1/4 x 1/2
B) 1/4 divided by 1/2
C) 1/4 + 1/2
D) 1/4 + 1/2
In llamas, coat color is controlled by a gene that exists in two allellic forms. If a homozygous yellow llama is crossed with a homozygous brown llama, the offspring will have gray coats. If two of the gray coated offspring were crossed, what percent of their offspring would have brown coats?
Which of the following descriptions does not apply to meiosis?
A) During the first division, the sister chromatids travel to opposite ends of the cell
B) The chromosome number of daughter cells is half that of the parent cell
C) The homologous chromosomes synapse and form tetrads prior to the first division
D) The cytoplasm of the cel and all its organelles are divided approximately in half
In rabbits, the gene for short hair (S) is dominant and the gene for long hair (s) is recessive. A cross between two rabbits produces a litter of six short-haired rabbits with green eyes and two short-haired rabbits with blue eyes. What is the most likely genotype of the parent rabbits in the cross?
A) ssgg x ssgg
B) SSGG x SSGG
C) SsGg x SsGg
D) SsGg x SSGg
In humans, hemophilia is an X-linked recessive trait. If a man and a woman have a son who has hemophilia, which of the following is true?
A) The mother carries an allele for hemophilia
B) The father carries an allele for hemophilia
C) The boys parental grandfather has hemophilia
D) Both parents carry the allele for hemophilia
Which of the following explains a significant low rate of crossing over between two genes?
A) The genes are located very close together
B) The genes are located on separate but homologous chromosomes
C) The genes code for proteins that have similar functions
D) The genes code for proteins that have very different functions
In a pedigree (image A), circles represent females and squares represent males: those who express a particular trait are shaded whereas those who do not are not shaded. Which pattern of inheritance bets explains the pedigree for this trait?
A) X-linked recessive
C) Autosomal recessive
D) Autosomal dominant
If a woman has A blood and her children have O blood, the father must have which of the following blood types?
A) A, B or O
B) AB or A
C) AB or B
D) O only
If a person with O blood were to have children with a person with AB blood, which of the following represents the bets prediction of the ratio of possible blood types for their offspring?
A) 3 Ia i and I Ib i
B) 1 Ia i and 1 Ib i
C) 1 Ia i and 2 Ia Ib and 1 Ib i
D) 9 Ia Ib and 3 Ia Ii and 3 Ib i and 1 ii
Two yellow mice with the genotype Yy are mated. After many offspring, 2/3 are yellow and 1/3 are not (2:1 ratio) Mendelian genetics dictates that this cross should produce offspring that were 1/4 YY (yellow) 1/2 Yy (yellow) and 1/4 yy (not yellow). What is the most likely conclusion from this experiment?
A) The mice did not bear enough offspring for the ratio calculation to be specific
B) Y is lethal in the homozygous form and causes death early in the development
C) Nondisjunction occurred
D) A mutation masked the effects of the Y allele
All of the following contribute to genetic recombination or variation in offspring except
A) random fertilization
B) independent assortment
C) crossing over
D) gene linkage
In cucumbers, warty (W) is dominant over dull (w) and Green (G) is dominant over orange (g). A cucumber plant that is homozygous for warty and green is crossed with one that is homozygous for dull and orange. The F1 generation is then crossed. If a total of 144 offspring is produced in the F2 generation, which of the following is the closest to the number of dull green cucumbers expected?
Chromosome number is reduced in meiosis. What event occurred to restore the diploid number of chromosomes?
A) Synapsis during prophase
D) DNA replication
Which of the following events is typical of the second meiotic division?
A) Paternal and maternal chromosomes assort randomly
B) The chromosome number becomes haploid
C) Crossing over between non-sister chromatids occurs
D) Sister chromatids migrate to separate poles
A cell with the diploid number of 6 could produce gametes with how many different combinations of maternal and paternal chromosomes?
The DNA content of a diploid cell is measured in the G1 phase. After meiosis I, the DNA content of one of the two cells produced would be
A) equal to that of the G1 cell
B) twice that of the G1 cell
C) one-half that of the G1 cell
D) one-fourth that of the G1 cell
Which of the following is true for both meiosis II and mitosis?
A) Sister chromatids separate
B) Homologous chromosomes separate
C) DNA replication precedes the division
D) Haploid cells are produced
Given the following recombination frequencies, what is the correct order of the genes on the chromosome? A-B 8 map units, A-D 25 map units, B-C 20 map units, B-D 33 map units
X-linked conditions are more common in men than in women because
A) genes associated with the X-linked conditions are linked to the X chromosome, some which determine maleness
B) men need to inherit only one copy of the recessive allele for the condition to be fully expressed
C) women simply do not develop the disease regardless of genetic composition
D) the sex chromosomes are more active in men than in women
Refer to figure B. If these 4 cells resulted from cell division of a single cell with diploid chromosome number 2n=4, what best describes what just occurred?
A) Normal meiosis
Refer to paragraph C. As a genetic counselor, you would explain to the parents that
A) the eggs must have been accidentally switched because the baby's blood type has to match one of his parents
B) each parent could have contributed one recessive allele, resulting in type-O blood
C) the eggs must have been accidentally switched because a type-A parent and a type-B parent could have any type of children except type O
D) it is possible for the baby to have type-O blood because type-O blood is inherited through a dominant allele
In regards to a baby's colorblindness, a sex-linked recessive trait, you explain that
A) colorblindness often appears randomly even if neither parent is colorblind
B) the baby's father must have a recessive allele for colorblindness
C) because colorblindness is a sex-linked trait, a son can inherit colorblindness if his mother has the recessive colorblindness allele
D) the eggs must have been accidentally switched because males inherit sex-linked traits only from their fathers
Independent orientation of chromosomes at metaphase I results in an increase in the number of
B) homologous chromosomes
C) possible combinations of characteristics
D) sex chromosomes
A mobile segment of DNA that travels from one location on a chromosome to another, making it an important element of genetic change.
A) DNA methylation
Binds to the promoter on DNA to initiate transcription.
A) RNA polymerase
D) Poly-A tail
A mutation is any change in the DNA sequences. Of the following mutation events, which one would have the most significant effect on the resulting polypeptide?
A) A nucleotide pair is added into a gene near its terminal end, altering the reading frame of the genetic code
B) A nucleotide and its complementary based are replaced, resulting in a new amino acid in translation
C) A nucleotide is altered that results in no change in the amino acid sequence due to redundancy
D) A nucleotide pair substitution occurs which results in the introduction of a stop codon
An example of post-transcriptional modification.
A) Poly-A tail
B) RNA polymerase
Which of the following has a DNA genome surrounded by a protein coat?
A) A virus
B) A prokaryotic cell
C) A retrovirus
D) A eukaryotic cell
Refer to the paragraph and image 5D to answer this question. In order to match the pilot's remains to the correct family using DNA profiling
A) the majority of the STR band must match
B) the bands for the site 13 must match
C) bands 5 and 7 must match
D) each of the 13 STR bands must match
Refer to figure 5b to answer this question: The segment of DNA shown in 5b has restriction site I and II, which create restriction fragments a, b and c. Which of the following gels produced by electrophoresis would represent the separation and identity of these fragments?
B) D or E
In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rule?
Refer to image 5a. When the electric field was applied, the fragments of DNA in each of the samples migrated to different locations on the gel. Which of the following explains the pattern shown here.
A) The fragments differ in their levels of radioactivity
B) The fragments differ in their charges; some were positively-charged whereas others were negatively-charged
C) The fragments differ in size
D) The fragments differ in solubility
A goat can produce milk containing the same polymers present in the silk produced by spiders when particular genes from a spider are inserted into the goat's genome. Which of the following reasons describes why this is possible?
A) Goats and spiders share a common ancestor and thus produce similar protein excretions
B) The universal nature of the genetic code allows for the production of identical proteins from different organisms as long as the DNA sequence is identical
C) The proteins in goats' milk and spiders' silk have the same amino acid sequence
D) Goats retain all the genes that were found in ancestral species and will express these proteins when activated by a gene insertion
Enzymes and energy are required for the synthesis of DNA and RNA. Which enzyme is correctly linked with its function?
A) Helicase alters the new DNA strands so it will coil into a double helix
B) Telomerase ensures that the transcription machinery starts with the codon AUG
C) DNA ligase joins together Okazaki fragments from the lagging strand
D) DNA polymerase oversees the binding of mRNA to the ribosomes
Which of the following is a laboratory application of restriction enzymes?
A) To block the replication of DNA
B) To prevent the translation of mRNA
C) To artificially force transcription of DNA
D) To cut DNA molecules at specific locations
RNA retroviruses such as HIV discharge both strands of RNA and molecules of reverse transcriptase into cells they infect. What is the purpose of the reverse transcriptase?
A) The host cells lack enzymes that can replicate the viral genome
B) The host cells rapidly destroy the viral RNA so more must constantly be made
C) The reverse transcriptase is required to translate viral mRNA into proteins
D) The reverse transcriptase binds to active sites of the lytic enzymes of the host cells
The synthesis of RNA from a DNA template is called
A bacterium is infected with an experimentally-constructed bacteriophage composed of the T2-phage protein coat the T4-phage DNA. The new phage produced by lysis of infected cells would have
A) T2 protein and T2 DNA
B) T4 protein and T4 DNA
C) T2 protein and T4 DNA
D) T4 protein and T2 DNA
Travels out of the nucleus and into the cytoplasm where it serves as a template in translation.
A) RNA polymerase
D) Poly-A tail
The addition of chemical groups (CH4, for example) to certain bases of DNA after DNA synthesis. This is thought to be an important control mechanism for gene expression.
The synthesis of polypeptides from the genetic information coded in the mRNA is called
Refer to paragraph 5c. The most likely method by which the mutated CCR5 gene prevents AIDS is by
A) being presented on immune system cells to target the virus for attack and destruction
B) directing the formation of lytic enzymes packaged in the lysosomes
C) blocking the protein channels that allow the virus to enter the cell
D) coding for mutant receptor proteins on the cell membrane, thus not allowing the entry of the virus
Refer to paragraph 5c. Which of the following shows the steps of a retroviral infection in the proper order.
A) Virus locates the host cell --> alters host cell DNA --> copies enter host cell nucleus --> nucleus leaves cell
B) Virus locates host cell --> penetrates cell membrane --> enters nucleus --> alters host cell DNA --> host cells produce copies of virus
C) Virus locates host cell --> penetrates host cell membrane --> viral RNA used to make copies of DNA --> host cell produces copies of the virus
D) Virus locates host cell --> enters nucleus --> alters host cell's DNA --> destroys host cell membrane
When a virus affects a bacterium by injecting its DNA and the genome of the virus is incorporated into the host cell, this is
A) the lytic cycle of the phase
B) retroviral infection
C) the lysogenic cycle of the phage
D) transposition by a virus
Which of these processes can cause an increase in the rate of transcription?
A) Acetylation of histone proteins
B) Negative feedback from accumulating product
C) Binding to the operator in an operon
D) Methylation of DNA, particularly the cytosine base
After eukaryotic transcription takes place, mRNA undergoes several modifications before leaving the nucleus to take part in translation. One of these is the cutting out of non-essential sections of mRNA and the subsequent splicing together of stretches of mRNA necessary for the final functioning molecule. Which of the following mRNA sections are spliced together into the finished mRNA molecule?
In genetic engineering, DNA ligase is used for which of the following purposes?
A) To create breaks in DNA in order to allow foreign DNA fragments to be inserted
B) To ensure that "sticky ends" of like DNA fragments do not re-anneal
C) To seal up nicks in newly-created recombinant DNA
D) To act as a probe for locating cloned genes
Refer to the paragraph and image 5d. Based on analysis of the STR sites shown, does the missing pilot belong to any of these three families?
A) Yes. Family 3 matches
B) Yes. Family 1 matches
C) Yes. Family 2 matches
D) No. None of the families match
Microarrays are single-stranded pieces of DNA of known genes, which are placed on a slide to determine whether these genes are being expressed in a particular tissue. For example, if the cells come from seedlings that are germinated and kept in the dark, the chlorophyll genes would not be active. Which of the following would you wash across the slide to determine that the chlorophyll genes are active in plants grown in the light?
A) A portion of the amino acid sequences of the chlorophyll molecule
B) Single-stranded cDNA made from mRNA transcribed from the chlorophyll genes
C) Cell fragments that include ribosomes and both tRNA and rRNA
D) mRNA transcribed from the plant grown in the dark
The human genome appears to have only about as many genes as the simple nematode worm C. elegans. Which of the following best explains how the more complex humans have relatively few genes?
A) The human genome has a large number of SNPs, which increases genetic diversity
B) The human genome has a high proportion of non-coding DNA
C) More than one polypeptide can be produced from a gene by alternative splicing
D) The human genes have unusually long introns involved in the regulation of the gene expression
Refer to image 5a. How many sites on DNA were cut by the particular restriction enzyme used in sample 1?
Binds to free amino acids in the cytoplasm.
B) Poly-A tail
D) RNA polymerase
PCR allows for target segments of DNA to be produced quickly by using heat to denature and separate strands of DNA; then cooling allows primers to attach to the single strands of the target DNA by adding nucleotides to the 3' end of each primer on the two strands. Why was this process considered so important that it earned Kary Mullis a Nobel Prize?
A) It enables selection of transformed cells that have taken up foreign DNA
B) It can produce multiple copies of even minute samples of DNA
C) It facilitates the introduction of plasmid DNA into a host cell
D) It is useful for isolating the source of DNA
Which of the following statements correctly describes a metabolic effect of cyanide, a poison that blocks the passage of electrons along the electron transport chain?
A) The pH of the intermembrane space becomes much lower than normal
B) Alcohol would build up in the mitochondria
C) NADH supplies would be exhausted and ATP synthesis would cease
D) No proton gradient would be produced and ATP synthesis would cease
Photorespiration occurs when the levels carbon dioxide are relatively low, and the enzyme rubisco catalyzes its release from the plant, rather than fixing it into an organic acid. CAM plants avoid photorespiration by
A) keeping their stomata open during the day
B) performing the Calvin cycle at night
C) fixing carbon dioxide into four carbon compounds in the mesophyll, which immediately releases carbon dioxide in the bundle sheath cells
D) fixing carbon dioxide into organic acids during the night; these acids then release the carbon dioxide during the day
A molecule that is so similar to the normal substrate that it compares for the active site of the enzyme.
B) Noncompetitive inhibitor
C) Feedback inhibitor
D) Competitive inhibitor
Refer to graph A. The graph below most accurately depicts the energy changes that take place in which of the following types of reactions?
Which of the following statements correctly links a process to its result?
A) The light reaction converts solar energy to chemical energy in the form of ATP and glucose
B) The Calvin cycle uses ATP and NADPH to convert CO2 to sugar
C) In chemiosmosis, electron transport chains pump H+ ions across a membrane from a region of high concentration to a region of low concentration
D) The Calvin cycle occurs in the thylakoid membrane and results in the capture of light energy
The process in photosynthesis that bears the most resemblance to chemiosmosis and oxidative phosphorylation in cell respiration is called
A) linear electron flow
B) ATP synthase coupling
D) substrate-level phosphorylation
The process by which a proton (hydrogen ion) gradient is used to produce ATP.
C) Electron transport
Fat Away prevents ATP from being made by
A) slowing down the citric acid cycle
B) destroying the H+ gradient that allows ATP synthase to work
C) preventing the conversion of NADH to NAD+
D) preventing glycolysis from occurring
Based on the figure below, which step of the citric acid cycle requires both NAD+ and ADP as reactants?
A) Step 1
B) Step 3
C) Step 4
D) Step 2
Glycolysis releases free energy held in the bonds of glucose, and this energy is held in these molecules.
A) ATP, NADH and pyruvate
B) ATP, CO2 and H2O
C) ATP, NADH and CO2
D) ATP, NADPH and RUBP
A series of membrane-embedded electron carries that ultimately create the hydrogen ion gradient to drive the synthesis of ATP.
B) Electron transport chain
D) Citric acid cycle
A process by which glucose is split to produce two ATP and lactic acid.
B) Electron transport
C) Citric acid cycle
How many "turns" of the Calvin cycle are required to produce one molecule of glucose?
The purpose of cellular respiration in a eukaryotic cell is to
A) synthesize carbohydrates from carbon dioxide
B) provide oxygen to the cell
C) break down carbohydrates to provide energy for the cell in the form of ATP
D) synthesize fats and proteins from carbon dioxide
When a cell breaks down glucose, only about 34% of the energy is captured in ATP molecules. What happens to most of the remaining 66% of the energy?
A) It is used to increase the order necessary for life to exist
B) It is released when the ATP molecules are hydrolyzed
C) It is stored as starch or glycogen for later use by the cell
D) It is lost as heat, in accordance with the second law of thermodynamics
The major product of the Calvin cycle is
C) ribulose and biophosphate
D) glyceraldehyde 3-phosphate
When light energy boosts electrons from the chlorophyll known as P680 to the primary electron acceptor, P680 has its electron "holes" filled by electrons from
B) photosystem II
C) photosystem I
D) carbon dioxide
Which of the following is mismatched with its location?
A) ATP synthesis--double membrane-surrounded chloroplast
B) Photosystem--thylakoid membrane
C) Electron transport chain--thylakoid membrane
D) Calvin cycle--stroma
Catabolic and anabolic pathways are often coupled in a cell because
A) their enzymes are controlled by the same activators and inhibitors
B) the free energy released from one pathway is used to drive the other pathway
C) the intermediates of a catabolic pathway are used in the anabolic pathway
D) both pathways use the same enzyme
Brown fat, which is found in newborn infants and hibernating mammals, has uncoupler proteins that, when activated, make the inner mitochondrial membrane leaky to H⁺. What is the function of brown fat?
A) Because it dissipates the proton gradient, it generates heat through cellular respiration without producing ATP, thereby raising the body temperature of hibernating mammals or newborn infants
B) Its main function is insulation in endothermic animals where brown fat is common
C) It lowers the pH of the intermediate space, which results in the production of more ATP per gram than is produced by regular oxidation of glucose or regular fat tissue
D) It produces more ATP than does regular fat and is also found in the flight muscles of ducks and geese, providing more energy for long distance migration
Based on your knowledge of the process of photosynthesis, the plant in the container placed under the red light would probably
A) absorb the same amount of carbon dioxide as the plants under both the green light and normal sunlight
B) absorb more carbon dioxide than the plants under green light
C) absorb no carbon dioxide
D) absorb less carbon dioxide than the plants under the green light
In an experiment, changing the pH from 7 to 6 resulted in an increase in product formation. From this we can conclude that
A) the enzyme's optimal pH is 6
B) the enzyme was in a more active shape at pH of 6
C) the temperature must have increased when the pH changed to 6
D) this enzyme works best at a neutral pH
The process by which a metabolic pathway is shut off by the product it produces.
A) Noncompetitive inhibitor
B) Feedback inhibition
D) Competitive inhibitor
The process by which glucose is split into pyruvate producing two ATP and two NADH.
C) Electron transport
Carbon dioxide absorption is an appropriate indicator of photosynthesis because
A) carbon dioixde is needed to produce sugars in the Calvin cycle
B) plants produce oxygen gas by splitting carbon dioxide
C) carbon dioxide is needed to complete the light reaction
D) the energy in carbon dioxide is used to produce ATP and NADPH
What are the final electron acceptors for the electron transport chains in the light reactions of photosynthesis and in cellular respiration?
A) Water in the light reaction and oxygen in respiration
B) Carbon dioxide in both
C) Oxygen in both
D) NADP+ in the light reaction and oxygen in respiration
One glucose molecule provides enough carbons for two trips through the citric acid cycle. How many molecules of ATP are directly produced in two trips through the citric acid cycle?
A molecule that binds to the enzyme at a site other than the active site, causing the enzymes to change shape and be unable to bind substrate.
B) Noncompetitive inhibitor
C) Negative feedback
D) Competitive inhibition
Describes a process by which an enzymes function at the active site may be either activated or inhibited by the binding of a regulatory molecule at a separate site.
A) Noncompetitive inhibitor
B) Allosteric interactions
C) Feedback inhibitions
D) Competitive inhibitor
The main products of the light reactions of photosynthesis are
A) ATP and CO2
B) NADPH and ATP
C) NADPH and NADH2
D) ATP and FADH2
When substance A was added to an enzyme reaction, product formation decreased. The addition of more substrate did not increase the product formation. From this we can conclude that substance A could be
A) product molecules
B) an allosteric enzyme
C) a noncompetitive inhibitor
D) a competitive inhibitor
Bacterial production of the enzymes needed for the synthesis of the amino acid tryptophan declines with increasing levels of tryptophan and increases as tryptophan and increases as tryptophan levels decline. This is an example of
A) irreversible inhibition
B) feedback inhibition
C) competitive inhibition
D) noncompetitive inhibition
Which of the following provides evidence that glycolysis is one of the first metabolic pathways to have evolved?
A) It is found only in prokaryotes whereas eukaryotes use mitochondria to produce ATP
B) It is nearly universal, occurs in the cytosol and does not involve oxygen
C) It produces ATP only by oxidative phosphorylation and does not involve redox reactions
D) It relies on fermentation, which is characteristic of archae and bacteria
Groups of photosynthetic pigment molecules organized the thylakoid membrane are called
Enzymes are organic catalysts. How do they increase the rate of chemical reactions?
A) By lowering the activation energy of the reaction
B) By raising the activation energy of the reaction
C) By decreasing the free energy change of the reaction
D) By increasing the free energy of the reaction
The fluid mosaic model describes the plasma membrane as consisting of
A) a phospholipid bilayer embedded with carbohydrates
B) carbohydrates and phospholipids that can drift in the membrane
C) two layers of phosopholipids with cholesterol sandwiched between them
D) diverse proteins embedded in a phospholipid bilayer
If you shut the system off and pressure was no longer applied to Tank A, you would expect
A) the water to flow equally in both directions
B) the water to flow from tank A to tank B
C) the water to flow against the concentration gradient
D) the water to reverse flow from tank B to tank A
Failure of this stage to occur prior to mitosis would result in daughter cells without sufficient DNA.
A) S phase
D) G1 Phase
Large molecules are moved out of the cell by which of the following processes?
A) Passive diffusion
How might the rate of sucrose into the cell be increased?
A) Make the membranes more permeable to hydrogen ions
B) Increase the cytoplasmic pH
C) Decrease the extracellular pH
D) Decrease the extracellular sucrose concentration
An organelle that is characterized by extensive, folded membranes and is abundant in cells that detoxify poisons such as liver cells.
A) Golgi apparatus
D) Smooth endoplasmic reticulum
These organelles are not found in red blood cells but are present in large numbers in muscle cells
A) Golgi apparatus
Cells of the pancreas will incorporate radioactively labeled amino acids into proteins. This "tagging" of newly synthesized proteins enables a researcher to track their location. In this case, we are tracking an enzyme secreted by pancreatic cells. What is its most likely pathway?
A) Golgi apparatus --> ER --> lysosome
B) ER --> Golgi apparatus --> vesicles that fuse with the plasma membrane
C) ER --> lysosomes --> vesicles that fuse with the plasma membrane
D) Nucleus --> ER --> Golgi apparatus
Large membrane-bound structures that contain hydrolytic-enzymes and that are found predominantly in animal cells.
C) Golgi apparatus
Many signal transduction pathways use second messengers to
A) relay a signal from the outside to the inside of the cell
B) relay a message from the inside of the membrane throughout the cytoplasm
C) transport a signal through the lipid bilayer portion of the plasma membrane
D) diffuse directly into the nucleus, turning on genes
Division of the cytoplasm is called
A) plasmodium response
If the S phase was eliminated from the cell cycle, the daughter cells would
A) be genetically identical to each other
B) have half the genetic material found in the parent cell
C) synthesize the missing genetic material on their own
D) be genetically identical to the parent
Salivary glands produce a large quantity of enzymes, which are transported out of the secretory cells. Which of the following organelles would be in abundance in these cells?
D) Smooth ER
If an animal cell was placed into a hypotonic solution, what would happen?
A) The cell would duplicate itself
B) The cell would shrink
C) The cell would swell and burst
D) The cell would adjust
The drawing above shows to solutions of glucose and sucrose in a U-tube containing a semipermeable membrane (which allows the passage os sugars). Which of the following accurately describes what will take place next?
A) Sucrose will diffuse from the right side to the left side
B) Glucose will diffuse from the left side to the right side
C) Glucose will diffuse from side B to side A
D) No net movement of molecules will occur
Which of the following component molecules of the plasma membrane is most important in the reception phases of cell signaling?
An organelle with a cis and trans face, which acts of the packaging and secreting center of the cell.
A) Rough ER
C) Golgi apparatus
Which of the following signal molecules pass through the plasma membrane and bind to intracellular receptors that move into the nucleus and function as transcription factors to regulate gene expression?
A) Neurotransmitters released into synapse between nerve cells
B) Testosterone, a steroid hormone
C) Yeast mating factors alpha and a
After the reverse osmosis system has been operating for 30 minutes, the solution in Tank A would
A) be hypertonic to tank B
B) be hypotonic to tank B
C) be isotonic to tank B
D) move by passive transport to tank B
The genetic material of the cell replicates to prepare for cell division.
White blood cells (WBCs) are more resistant to lysis than red blood cells (RBCs). When looking at a sample of blood for WBCs, what could you do to reduce interference from RBCs?
A) Mix the blood in an isotonic solution, allowing the WBCs to float to the top
B) Mix the blood in a salty solution to cause the RBCs to lyse
C) Mix the blood in a hypertonic solution, which will cause the RBCs to lyse
D) Mix the blood in a hypotonic solution, which will cause the RBCs to lyse
An ATP-powered pump that transports a specific solute can indirectly drive the active transport of another solute in a mechanism called cotransport. This is shown in the figure above. The cotransporter protein is able to use the diffusion of H⁺ ions down their electrochemical gradient into the cell to drive the uptake of sucrose into the cell. By what process are H⁺ ions beings moved in this figure?
A) Simple diffusion
C) Active transport
D) Facilitated diffusion
If an animal cell were placed into a hypertonic solution, what would happen?
A) The cell would adjust
B) The cell would divide to adjust
C) The cell would swell and burst
D) The swell would shrink
Based on their function, you would expect melanocytes in the skin to have a higher than usual number of
A) Golgi bodies
Look at the same figure, but let's assume the membrane is not freely permeable to both glucose (C₆H₁₂O₆) and sucrose (C₁₂H₂₂O₁₁) but only to the smaller of the two sugars. Now what results would you predict?
A) Glucose will diffuse fromt he right side to the left side
B) Glucose will diffuse from the left side to the right side
C) Sucrose will diffuse from the right side to the left side
D) Sucrose will diffuse from the left side to the right side
Small, nonpolar, hydrophobic molecules such as fatty acids
A) require transport proteins to pass through a membrane's lipid bilayer
B) easily pass through a membrane's lipid bilayer
C) very slowly diffuse through a membrane's lipid bilayer
D) are actively transported across the cell membrane
Prokaryotic and eukaryotic cells have all of the following structures in common EXCEPT
A) a cytoplasm
C) linear chromosomes
D) a plasma membrane
The cell is carrying out its typical functions, not engaged in producing molecules necessary for division.
D) Gap 1
If this did not occur, daughter cells would have two complete sets of chromosomes.
D) Gap 1
Insulin is a protein synthesized in the cytoplasm of pancreas cells and then transported to the plasma membrane where it enters the bloodstream. Which of the following summarizes the pathways for insulin though a pancreatic cell?
A) Nucleus --> vesicle --> rough ER --> plasma membrane
B) Rough ER --> Golgi body --> vesicle --> plasma membrane
C) Smooth ER --> nucleus --> vesicle --> plasma membrane
D) Ribosomes --> Golgi body --> vesicle --> plasma membrane
Which of the following processes could result in the net movement of a substance into a cell if the substance is more concentrated in the cell than in the surroundings?
A) Active transport
B) Facilitated diffusion
When sister chromatids begin to separate.
Which of the following statements regarding the cell-cycle control system is false?
A) The cell-cycle control system triggers and controls major events in the cell cycle
B) The cell-cycle control system receives messages from outside the cell that influence cell division
C) The cell-cycle control system includes fluctuating levels of cyclins and cyclin-dependent kinases
D) The cell-cycle control system operates independently of the growth factors
If the melanin production were not sufficient to prevent UV damage to the DNA, which of the following would you expect?
A) Peeling of the skin due to sebaceous glands shutting down
B) Apoptosis and lysis of damaged cells
C) Decreased cell division
D) A decrease in the rate of melanin production
Which of the following can activate a protein by transferring a phosphate group to it?
B) Protein kinase
C) G protein
D) Protein phosphatase
Earl Sutherland reviewed the Nobel Prize for his discovery of cAMP as a second messenger. Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells?
A) Enzymatic activity was proportional to the amount of calcium added to a cell-free extract
B) Glycogen breakdown was observed when the epinephrine and glycogen phosphorylase were combined
C) Receptor studies indicated that epinephrine was a ligand
D) Glycogen breakdown was observed only when epinephrine was administered to intact cells
Which of the following uses passive transport, without protein channels, to move materials across the cell membrane?
A) The movement of carbon dioxide across the cell membrane
B) The uptake of glucose by the microvilli of cells lining the stomach
C) The movement of insulin across the cell membrane
D) Depolarization of a muscle cell
In cell signaling, how is the flow of specific ions regulated?
A) Cytoskeleton rearrangement
B) Opening and closing of ligand-gated ion channels
Protein phosphorylation is commonly involved with all of the following EXCEPT
A) activation of receptor tyrosine kinase
B) regulation of transcription by extraceullar signalling molecules
C) activation of G-protein coupled receptors
D) enzyme activation
What is a G protein?
A) A membrane-bound enzyme that converts ATP to cAMP
B) A protein on the cytoplasmic inside of a membrane that becomes activated by a receptor protein
C) A guanine nucleotide that converts between GDP and GTP to activate and inactivate relay proteins
D) A specific type of membrane receptor protein
The tremendous variation and unique properties of proteins are most likely a result of
A) peptide bonds linking amino and carboxyl groups
B) interactions between the R groups of amino acids
C) the sequence of amino acids in the primary structure of the protein
D) hydrogen bonds linking the amino acids
Beaker A is distilled water with a potato core in the water. The water potential is 0.4 and the solute potential is -0.4. Baker B is distilled water with a potato core; the water potential is 0.2 and the solute potential is -0.4. Which of these answers would best describe this example?
A) The water potential of the beaker can not be calculated; water potential of the potato core is 0.2
B) The water potential in the beaker is 0 and the water potential of the potato core is -0.2
C) The water potential in the beaker is 0 and the water potential of the potato core is 0.
D) The water potential in the beaker is 0 and the water potential of the potato core is 0.2
Which of the macromolecules below could be structural parts of the cell, enzymes or involved in cell movement or communication?
D) Nucleic acid
Water is an excellent solvent. Select the property that justifies this statement.
A) It forms hydrogen bonds with itself so cohesion is possible.
B) As a polar molecule, it can surround and dissolve ionic and polar molecules.
C) It is a liquid and will adhere to many substances.
D) It forms ionic bonds with ions, hydrogen bonds with polar molecules and hydrophobic interactions with nonpolar molecules.
Which of the following statements regarding carbon is false?
A) Carbon has the capacity to form polar covalent bonds with hydrogen
B) Carbon has the capacity to form single and double bonds
C) Carbon has the ability to bond together to form extensive branched and unbranched carbon skeletons
D) Carbon has the ability to form covalent bonds with 4 other atoms
The process by which protein conformation is lost or broken is
D) dehydration synthesis
The linkages between monomers of proteins are called
A) beta bonds
B) peptide bonds
C) alpha helix bonds
D) ionic bonds
Hydrolysis is involved in which of the following?
A) Peptide bond formation between amino acids to form a protein
B) Hydrogen bond formation between nitrogen bases and nucleic acids
C) The digestion of sucrose, a disaccharide, to its monomers of glucose and fructose
D) Formation of starch, a polysaccharide, from monomers in glucose
The major class of biological molecules that are not polymers.
B) Alpha helix
D) Peptide bonds
You're the manager of a factory that produces enzyme-washed blue
jeans (the enzymes lighten the color of the denim, giving a
"faded" appearance). When the most recent batch of fabric
came out of the enzyme wash, however, the color wasn't light enough to
meet your standards. Your quality control laboratory wants to do some
tests to determine why the wash enzymes didn't perform as
Which hypothesis is most likely to be productive for their initial investigation?
A) The dye in the fabric may have hydrolyzed the fatty acids in
B) The three-dimensional structure of the proteins may have been altered.
C) There may not have been enough phospholipids for the volume of fabric.
D)The nucleotide chain of the enzymes may be incorrectly formed.
Which of the following molecules would contain polar covalent bonds?
Based on your understanding of enzyme structure, which of the following would you recommend that they also investigate?
A) The temperature of the liquid in the washing vat
B) The primary structure of the enzyme
C) How long the fabric has been in storage
D) The manufacturer of the fabric
Which of these is the formula for calculating solute potential?
A) Pi = PVT
B) PV = nRT
C) water potential - solute potential
A secondary structure in proteins.
A) Beta-pleated sheets
C) Alpha helix
D) Peptide bonds
The formula for calculating water potential is
A) Solute potential + pressure potential
B) Pressure potential divided by water potential
D) Pressure potential minus water potential
Which list of components characterizes RNA?
A) Phosphate group, deoxyribose and uracil
B) Phosphate group, ribose and thymine
C) A phosphate group, deoxyribose and uracil
D) A phosphate group, ribose and uracil
How are the two animo acids attached together?
A) Amino group to amino group
B) Carboxylic acid group to carboxylic acid group
C) Amino group to carboxylic acid group
D) Carbon atom to carbon atom
The molecule formula for glucose is C6H12O6. What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?
An organic compound that is composed of carbon, hydrogen and oxygen in a 1:2:1 ratio.
C) Nucleic acid
Draw three water molecules together. Show the intramolecular attraction between these molecules. Based on the drawing, the hydrogen bonds are between
A) an oxygen and a hydrogen atom of the same water molecule
B) two oxygen atoms
C) an oxygen and a hydrogen atom of different water molecules
D) two hydrogen atoms
The partial negative charge at one end of a H2O molecule is attracted to a partial positive charge of another H2O molecule? What is this type of attraction called?
A) A hydrogen shell
B) A hydrogen bond
C) An ionic bond
D) Polar covalent bond
A structural carbohydrate found in plants.
If three molecules of a fatty acid that has the formula C16H22O2 are joined to a molecule of glycerol C3H8O3, then the resulting molecule would have the formula
Which of the following pairs of base sequences could form a short stretch of a normal double helix of DNA?
A) 5'-AGCT-3' with a 5'-TCGA-3'
B) 5'-AGGA-3' with a 3'-UGGU-5'
C) 5'-GCGC-3' with a 5'-TATA-3'
D) 5'-ATGC-3' with a 5'-GCAT-3'
The plasma membrane is composed of several different macromolecules. Which macromolecule serves as the fluid interface between intracellular and extracellular environments?
If a dipeptide were digested, how would it be reduced to amino acids?
A) By reduction in digestive fluid pH in the stomach
B) Through the removal of the functional groups at either end
C) By a dehydration reaction that removes water
D) Through a hydrolysis reaction in which water is added
The water potential of distilled water is
Polymers of carbohydrates and proteins are all synthesized from monomers by which of the following processes?
A) Ionic monomers
C) Dehydration reactions
D) The joining of monosaccharides
If the pH of a solution is decreased from 7 to 6, it means that the concentration of
A) OH- has increased 1/7 of what it was at pH of 7
B) OH- has increased 10 times from what it was at pH of 7
C) H+ has increased 10 times what it was at pH of 7
D) H+ has decreased 1/10 of what it was at pH of 7
Recall the structure of a typical amino acid and how the water molecule has two distinct ends. Which of the two functional groups are found in amino acids?
A) Carboxyl and anime
B) Hydroxyl and carbonyl
C) Amine and sulfydrl
D) Phosphate group and nitrogenous base
Because of the unique properties of water associated with hydrogen bonding, water evaporates from the pores on leaves of plants and draws up water molecules in continuous chains from the roots through the vascular tissue of plants. Which of these groups of terms best describes the process and properties of water that best explain this?
A) Adhesion, cohesion and transcription
B) Adhesion, cohesion and translocation
C) Cohesion, hybridization and transpiration
D) Cohesion, adhesion and transpiration
The condition in which there are barriers to reproduction between individuals of the same species because they are separated by a portion of a mountain range is referred to as
A) mechanical isolation
B) geographic isolation
C) gametic isolation
D) temporal isolation
Which of the following statements best expresses the concept of punctuated equilibrium?
A) Very small changes in the genome of individuals eventually lead to the evolution of a population
B) The five conditions of Hardy-Weinberg equilibrium will prevent populations from evolving quickly
C) Evolution changes in rapid bursts of change alternating with long periods in which species remain relatively unchanged
D) Profound change over the course of geologic history is the result of an accumulation of slow, continuous processes
In a particular bird species, individuals with average-sized wings survive severe storms more successfully than other birds in the same population with longer or shorter wings. This illustrates which of the following modes of selection?
A) Directional selection
B) Stabilizing selection
C) Diversifying selection
D) Artificial selection
This results in a new population with a limited gene pool, often seen when a small population is separated from the larger population.
A) The bottleneck effect
B) Homologous structures
C) Analogous structures
D) The founder effect
One result of evolution from a common ancestor; exhibited by certain structures with similar features having different functions.
A) The bottleneck effect
B) Homologous structures
C) Analogous structures
D) The founder effect
A result of drastic reduction in population size, such as the reduction of the California condor population to nine individuals.
A) The bottleneck effect
B) Homologous structures
C) Analogous structures
D) The founder effect
Features that have evolved independently to serve similar functions but do not represent evolutionary relatedness.
A) The bottleneck effect
B) Homologous structures
C) Analogous structures
D) The founder effect
A marsupial species found only in Australia has evolved to eat tree leaves, be diurnal and raise its young until they are of reproductive age. A grazing placental mammal species found in Africa has also evolved to eat tree leaves, be diurnal and raise its young until they are of reproductive age. This is an example of which of the following types of evolution?
A) Divergent evolution
B) Species-specific evolution
C) Convergent evolution
D) Neutral evolution
One general pattern that will maintain two related groups as separate species requires their gamest to not combine. These are called prezygotic barriers. Select the one example here that does not describe this type of isolating mechanism.
A) Hybrid breakdown
B) Behavioral isolation
C) Temporal isolation
D) Mechanical isolation
Banded iron formations in marine sediments provide evidence of
A) the crashing of meteorites onto Earth, possibly transporting abiotically produced organic molecules from space
B) oxidized iron layers in terrestrial rocks
C) the accumulation of oxygen in the seas from the photosynthesis of cyanobacteria
D) the evolution of photosynthetic archaea near deep-sea vents
Which of the following constitutes the smallest unit capable of evolution?
A) An individual
B) A family unit
C) A population
D) A community
Which of the following would not be important in Darwin's theory of evolution?
A) Acquiring genetic change during the life span of the organism contributes to evolution
B) More individuals are born in a population than will survive to reproduce
C) Natural selection occurs as a result of the differing reproductive success of individuals in a population
D) A result of evolution is the adaptation of a population of organisms to their environment
In a certain group of rabbits, the presence of yellow fur is the result of a homozygous recessive condition in the biochemical pathway producing hair pigment. If the frequency of the allele for this condition is 0.09, which of the following is the closest to the frequency of the dominant allele in this population?
In a population of squirrels, the allele that causes bushy tail (B) is dominant, while the allele that causes bald tail is recessive (b). If 64% of the squirrels have a bushy tail, what is the frequency of the dominant allele?
Mice that are homozygous for a lethal recessive allele die shortly after birth. In a large breeding colony of mice, you find that a surprising 5% of all newborns die from this trait. In checking lab records, you discover that the same proportion of offspring have been dying from this trait in this colony for the past three years. (Mice breed several times a year and have large litters.) How might you explain the persistence of this lethal allele at such a high frequency?
A) Homozygous recessive mice have a reproductive advantage, which helps to maintain the frequency of the allele
B) The rapid reproductive rate is coupled with a large mutation rate, which results in multiple copies of this lethal allele
C) There is some sort of heterozygote advantage and perhaps selection against the homozygous dominant trait
D) Because this is a diploid species, the recessive allele cannot be selected against when it is in the heterozygote
Morphological and genetic comparisons group 30 species of snapping shrimp into 15 pairs of closely related species. In sympatric selection, a new species may arise in the same area as an existing species, where in allopatric speciation, some geographical isolating mechanism is present. What is the best explanation for the fact that one member of each pair lives on the Atlantic side of the Isthmus of Panama, whereas the other member of each pair lives on the Pacific side?
A) Different predator pressures in the Atlantic and Pacific selected for differences, resulting in the reproductive isolation of these species
B) The pairs of species arose by allopatric speciation when the Isthmus of Panama separated their ancestral species
C) The 30 species of snapping shrimp evolved by sympatric speciation before the Isthmus of Panama formed
D) These 15 pairs of species illustrate the pattern of punctuated equilibrium, in which most speciation events take place in a short period of time
Sympatric evolution occurs when a new species arises in the same area as an existing ancestral species. Which of the following can lead to sympatric speciation?
A) Migration of a small number of individuals to a geographically remote area
B) A natural disaster cuts off contact between members of a population
C) A flood causes a newly-formed river, separating segments of a population
D) A mutation event results in offspring that are fertile tetraploids
Mitochondria and plastids contain DNA and ribosomes and make some, but not all, of their proteins. Some of their proteins are coded for by nuclear DNA and produced in the cytoplasm. What may explain this division of labor?
A) Over the course of evolution, some of the original endosymbiont's genes were transferred to the host cell's nucleus
B) The host cell's genome always included genes for making mitochondrial and plastid proteins
C) The smaller prokaryotic ribosomes in these organelles cannot produce the eukaryotic proteins required for their functions
D) Some mitochondria and plastid genes were contributed by early bacterial prokaryotes that shared genes with other primitive cells
Mothers and teachers have often said that they need another pair of eyes on the backs of their heads. And another pair of hands would come in handy in many situations. You can imagine that thees traits would have been advantageous to our early hunter-gatherer ancestors as well. According to sound evolutionary reasoning, what is the most likely reasoning for hwy humans do not have these traits?
A) Because they actually would not be beneficial to the fitness of individuals who possessed them. Natural selection always produces the most beneficial traits for a particular organism in a particular environment.
B) Because every time they have arisen before, the individual mutants bearing these traits have been killed by chance events. Chance and natural selection interact.
C) Because these variations have probably never appeared in a healthy human. Tetrapods share a four-limbed, two-eyed body plan; natural selection can only edit existing variations.
D) Because humans are relatively young species. Given enough time for adaptation, it is inevitable that the required adaptations will arise.
The phylogenetic tree illustrates the evolutionary relationships of tetrapods and was constructed using both anatomical and DNA sequence data. Using evidence from this tree, which statement most accurately reflects the relationship of mammals to amphibians and birds?
A) Mammals are more closely related to amphibians and likely share more DNA sequences
B) Mammals are more closely related to amphibians because they share anatomical similarities
C) Mammals are more closely related to birds because they share a more recent common ancestor
D) Mammals, birds and amphibians are all equally related because they share a common ancestor at the second branch point
According to the figure above, which pair of organisms shares the most recent common ancestor?
A) Lungfish and amphibian
B) Amphibian and lizard
C) Mammal and crocodile
D) Lizard and ostrich
According to the figure above, the group most closely related to lizards and snakes are
D) hawks and other birds
This figure shows the change of a population over time. Which statement best describes the mode of selection depicted in the figure?
A) Stabilizing selection, which causes the average color of the population to be pushed toward an intermediate value
B) Directional selection, which causes the average color to become darker over time
C) Diversifying selection, which causes the average color to become either darker or lighter over time
D) No selection, because too many of the original population are lost over time
In plants, speciation can occur when the offspring receive extra sets of chromosomes. This is referred to as being polyploid. Which species of wheat shown is polyploid? The uppercase letters represent not genes but sets of chromosomes.
A) T. monococcum
B) The AB sterile hybrid
C) T. turgidun
D) T. tauschii
The evolution of Homo floresiensis is an example of
A) sympatric selection, which occurs when a new species develops in the midst of an ancestral species, often by polyploidy
B) allopatric speciation, in which a new species arises when two populations are geographically separated
C) adaptive radiation, which occurs when new niches become available and are filled by new species
D) hydbridization, which occurs when two species interbreed
If H. floresiensis were reunited with H. erectus at much later date but the two populations could no longer interbreed, which would be a scientifically plausible conclusion about their incompatibility?
A) H. floresiensis is no longer fertile as a species
B) H. floresiensis had been isolated for more than 50,000 years
C) H. floresiensis has become less fit than H. erectus
D) Reproductive barriers had evolved between the two species
Which of the following groups is best characterized as being eukaryotic, mutlicellular, heterotrophic and without a cell wall?
Systematists categorize all living creatures into what 3 domains?
A) Bacteria, Animalia, Eukarya
B) Bacteria, Archaea, Eukarya
C) Archaea, Plantae, Eukarya
D) Protista, Plantae, Eukarya
Which of the following is a symbiotic relationship in which both organisms benefit?
Place the following groups of plants in order beginning with those that first appeared on Earth.
A) Moss, angiosperms, ferns, gymnosperms
B) Moss, ferns, gymnosperms, angiosperms
C) Moss, ferns, angiosperms, gymnosperms
D) Seed plants, cone-bearing plants, brytophytes
Evolution of which feature enabled vertebrates to reproduce successfully on land?
A) The amniote egg
B) Origin of limbs with digits
C) Flagellated sperm
D) Keratinized body covering
Which statement is not supported by the cladogram?
A) The lineage leading to salamanders was the first to diverge from the original lineages
B) Humans more closely related to goats than lizards
C) Salamanders are as closely related to goats as to humans
D) Lizards are more closely related to salamanders than to humans
Genetic variation in bacterial populations is introduced in several ways. Select the process that will not introduce genetic variation in bacteria.
Shared derived characteristics are used to create cladograms. Which is a correct description of them?
A) They are features that characterize the species on a branch of a phylogenetic tree
B) They can be determined through a (incomprehensible--poor scanning job) comparison of related genes of a group of species
C) They are homologous structures that develop during adaptive radiation
D) They can be used to identify species but not higher taxa
In a comparison of birds and mammals, having four appendages is
A) a shared ancestral characteristic because it originates in an ancestor of the taxa
B) a shared derived characteristic because it is shared by all mammals
C) a characteristic useful for distinguishing birds from mammals
D) an example of analogy rather than homology
An outgroup is a species from an evolutionary lineage that is known to have diverged before the lineage under study. If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup?
B) Domestic cat
In the 1920s, Frederick Griffith conducted an experiment in which he mixed the dead cells of a bacterial strain that can cause pneumonia with live cells of a bacterial strain that cannot. When he cultured the live cells, some of the daughter colonies proved able to cause pneumonia. Which of the following processes of bacterial DNA transfer does this experiment demonstrate?
Molecular data can be used to assess relationships among the major groups of living organisms whose common ancestors lived millions or billions of years ago. Similar techniques can be used to assess relationships among populations within a species. How can molecular techniques be useful for such varied comparisons?
A) Studying the relationships among different populations of a single species can be just as effective as studying the relationships of major biological groups if you look at many more genes.
B) The same data can be used for any comparison with equal accuracy.
C) Faster-evolving gene sequences provide better data for comparisons among close relatives, whereas very slowly evolving sequences work best for distantly-related taxa.
D) The relationships between very different groups such as bacteria and whales cannot be assessed.
If you were constructing a phylogenetic tree for the evolution of birds, which characteristics found in Archaeopteryx might provide evidence that birds and dinosaurs had a common ancestor?
A) Feathers, wings, wishbone
B) Teeth, feathers, keeled sternum
C) Teeth, flat sternum, claws
D) Keeled sternum, claws, long forelimbs
An experimental forest ecosystem is enclosed in a sealed greenhouse. The entire ecosystem, including the air and soil, is treated with an extremely potent fungicide that kills all fungal life stages including spores. What will probably happen next?
A) Tree growth will increase because the dead fungi will act as a fertilizer
B) Plants will enjoy a long-term increase in growth and survival because of the removal of fungal pathogens
C) Dead organic matter will accumulate on the forest floor; plant growth will decline because of a lack of nutrients and the loss of mycorrhizal partners.
D) Certain animal populations may decrease due to loss of their fungal food sources, but otherwise the forest will be largely unchanged.
The movement of life onto land required numerous adaptations to obtain water, prevent water loss and reproduce. Plants have a waxy covering, known as cuticle, on their leaves that helps them conserve water. Seeds have several plant groups to reproduce effectively on dry land by protecting the embryo from water loss. Which of these pairs correctly shows a trait that prevents water loss and a trait that protects the embryo.
A) Reptiles have keratinized scales and produce amniote eggs
B) Mammals have fur on hair and internal fertilization
C) Amphibians have a moist skin and external fertilization
D) Roundworms have a cuticle and are hermaphroditic
This is a figure in which the viruses that infect bacteria carry genes from one host cell to another. There is a process in sexually reproducing eukaryotes that uses enzymes similar to the ones that result in the incorporation of A+ gene into the host genome shown in the figure. Which of these represents the similar process in eukaryotes?
A) Fertilization during sexual reproduction
B) Independent assortment during mitosis
C) Transduction during bacterial recombination
D) Crossing over during meiosis
Monophyletic clades include a common ancestor and all its descendants. According to this figure, which grouping represents a monophyletic clade?
A) Lemurs, tarsiers, New World monkeys and Old World monkeys
B) New World monkeys and Old World monkeys
C) Gibbons, orangutans, gorillas and chimpanzees
D) Gorillas, chimpanzees and humans
Which of these relationships is depicted on this cladogram?
A) Humans have descended from chimpanzees
B) Gibbons are the common ancestor of orangutans, gorillas, chimpanzees and humans
C) Old World monkeys and new World monkeys diverged approximately 35 million years ago
D) Gorillas are equally related to orangutans and chimps
Which of the following processes is responsible for the bending of the stem of a plant toward a light source?
A) The amount of chlorophyll produced on the side facing the light increases
B) The rate of cell division on the side facing the light increases
C) The rate of cell division on the side away from the light increases
D) The cells on the side of the stem away from the light elongate
Which of the following mechanisms is most important in the movement of water from roots to leaves in the xylem?
A) The effect of gravity
B) Root pressure
Hydrogen bonding plays a particularly important role in which plant process?
A) Bulk flow of solutes from source to sink
B) Photoperiodism, resulting in flowering
C) Attraction of the sperm and egg
D) The transpiration-cohesion-tension mechanism
In a mesophyll cell of a leaf, the synthesis of ATP takes place in which of the following cell organelles?
A) Chloroplasts and mitochondria
B) Mitochondria only
C) Nucleoli and mitochondria
D) Ribosomes and mitochondria
Which of these does not play a significant role in enhancing uptake of water by a plant?
A) Root hairs
B) Large leaf surface area
D) Gravitational force
How does the sperm of flowering plants reach the egg?
A) Via a pollen tube that grows from the pollen grain through the carpel tissues to the egg
B) Via raindrops of a dew film that allows the sperm to swim from the male plant to the female plant
C) Usually via an insect, which places sperm in the ovary while probing for nectar
D) By actively swimming down through the style to the egg
Which of the following plant structures will become the seed?
A) A flower
B) An embryo
C) An ovule
D) An ovary
In order to flower, short-day plants require a period of
A) light greater than a critical period
B) darkness greater than a critical period
C) light less than a critical period
D) darkness less than a critical period
If a long-day plant has a critical length of 9 hours, which 24-hour cycle would prevent flowering?
A) 16 hours light/8 hours dark
B) 14 hours light/10 hours dark
C) 15.5 hours light/8.5 hours dark
D) 4 hours light/8 hours dark/4 hours light/8 hours dark
Select the activity that does not occur in a signal transduction pathway.
A) Activation of the receptor by a relay molecule
B) Expression of specific genes
C) Activation of protein kinases
D) Phosphorylation of transcription factors
The figure shows key elements of Went's experiment. Which plant shows auxin stimulating elongation in the left side of the plant only?
A) Plant A
B) Plant B
C) Plant C
D) Plant D
What prior knowledge must Went have had to design this experiment as shown?
A) Plants respond to gravity as well as light
B) Compounds produced in the shoot tip have an effect on phototropism
C) Placing an agar block on a seedling will stimulate its growth
D) Photosynthesis is concentrated in cells of the shoot tip
In Went's experiment, observe what happens to both plants with treatment D, agar blocks with no chemicals. What conclusion can be drawn from this?
A) These plants serve as the control because they have no chemical
B) It is necessary to add chemical to the block to get bending
C) The addition of the chemical causes elongation of cells
D) The mechanical irritation of the agar block is responsible for the bending
In plants, translocation, the movement of solutes in the phloem, occurs as a result of
A) a difference in water potential between a sugar source and a sugar sink
B) evaporation of water through the stromata
C) cohesion of water molecules to each other and adhesion to the transport tubes
D) release of auxin in response to loss of water in the xylem
What is the signal and its receptor in this pathway?
A) Ca2+ is the signal, a membrane protein is the receptor
B) Light is the signal, a cytoplasmic protein is the receptor
C) cGMP is the signal, protein kinase is the receptor
D) The protein kinases are the signal, transcription factors are the receptors
Which step in this pathway converts and amplifies the signal, resulting in numerous active molecules?
A) Step 1
B) Step 2
C) Step 3
D) Both steps 1 and 3
Which of the following would occur if Ca2 channels were not functional?
A) Reception would be blocked, and phytochrome would not be activated
B) cGMP molecules, the second messengers, would not be produced
C) Transcription and translation of the de-etiolation proteins would not occur
D) Transcription factor 2 would not be produced
Which of the following is required for ALL living things in order for gas exchange to occur?
C) Moist membranes
During transmission across a typical chemical synapse,
A) the binding of neurotransmitters to receptors initiates exocytosis
B) action potentials trigger chemical changes that make the synaptic vesicles fuse with each other
C) vesicles containing neurotransmitters diffuse to the receiving cell's plasma membrane
D) neurotransmitter molecules bind to receptors in the receiving cell's plasma membrane
Epinephrine (adrenaline) raises blood glucose levels, increases metabolic rate and increases blood flow to skeletal muscles. Which of the following is most likely to result in a release of epinephrine from the adrenal glands?
A) Falling asleep in front of the TV
B) Watching a checkers tournament
C) Doing yoga
D) Fleeing from a harmful situation
Oxygen is transported in human blood by which type of cell?
A) Erythrocytes (red blood cells)
B) Leukocytes (white blood cells)
C) Lymphocytes (type of white blood cell)
Once the threshold potential is reached after a neuron is stimulated, which of the following occurs?
A) The interior of the cell becomes negative with respect to the outside
B) K+ channels open
C) Na+ channels close
D) An action potential is generated
Salivary amylase, an enzyme secreted in saliva, begins the breakdown of molecules that will produce monosaccharides. Which category of nutrients does this enzyme digest?
D) Nucleic acids
Pepsin in the stomach begins the enzymatic digestion of protein. What molecules are the end products of protein digestion?
A) Nucleic acids
B) Amino acids
C) Fatty acids
In the mammalian heart, the sinoatrtial (SA) node generates electrical impulses and is sometimes called the pacemaker of the heart. Which of the following correctly describes its function?
A) It delays the nerve impulse to the walls of the ventricle
B) It controls the action of the atrioventricular valve
C) It regulates the amount of blood that exits with each heartbeat
D) It sets the rate and timing of cardiac muscle contraction
Fluid lost from the capillaries and not reabsorbed is returned to the blood via
A) the venous system
B) the arteriole system
C) the lymphatic system
D) capillary beds
In the blood, carbon dioxide is primarily transported in what way?
A) By hemoglobin
B) As carbon monoxide
C) In erythrocytes (RBCs)
D) As bicarbonate ions
Barrier defenses are an important nonspecific arm of the immune system. All of the following are barrier defenses EXCEPT
C) lysozyme in saliva
An immune response to a specific antigen generates the production of which type of cell that launches an attack the next time that same antigen infects the body?
A) Effector cells
B) Memory cells
C) T cells
Muscle cell contraction occurs via
A) contraction of the sacroplasmic reticulum
B) plasma membrane
C) flow of calcium ions out of the cell
D) sliding of the thin filaments by the thick filaments
The succession of rapid cell division that follows fertilization is called
Which of the following correctly describes a reflex arc?
A) Receptor, sensory neuron, effector
B) Motor neuron, associative neuron, sensory neuron
C) Receptor, motor neuron, sensory neuron
D) Effector, sensory neuron, receptor
Which of the following is released into the synaptic cleft and acts as a signaling molecule?
A) Sodium ions
B) Calcium ions
D) Receptor proteins
Which arrow in this schematic view of the nephron shows reabsorption
A) Arrow A
B) Arrow B
C) Arrow C
D) Arrow D
What type of cell acts as an intermediary between humoral and cell-mediated immunity?
A) Plasma cell
B) Cytotoxic T cell
C) B cell
D) Helper T cell
What occurs during gastrulation?
A) Individual cells of the embryo divide but do not grow
B) Cytoplasmic determinants signal the development of right and left sides of the embryo
C) A hollow blastula is changed into an embryo that has three tissue layers
D) A neural tbe is created by invagination of the ectoderm
Which structure in the diagram of the human brain is the center for the control of the involuntary centers for breathing, heartbeat, respiration and digestion?
A) Part B
B) Part C
C) Part D
D) Part E
Which of these correctly describes the autonomic nervous system?
A) It integrates sensory impulses to the brain
B) It carries signals to and from skeletal muscles
C) It regulates the internal environment of the body
D) It is part of the central nervous system
Which part of the figure shows an active plasma B cell?
A) Part A
B) Part B
C) Part C
D) Part D
Which part of this diagram of the human brain depicts the brain region that coordinates muscular functions such as walking and tying shoelaces?
A) Part A
B) Part B
C) Part C
D) Part E
Based on your understanding of homeostasis, for negative-feedback control of blood glucose levels to function properly
A) the control center for glucose must be somewhere in the digestive system
B) there must be sensors that monitor blood glucose levels
C) there must be several other hormones involved (in addition to insulin and glucagon)
D) the body must prevent glucose levels from changing even slightly
If you hadn't eaten for several hours, how would your glucose levels be returned to the set point?
A) Insulin levels would be released to move glucose into cells and the liver
B) Glucagon would be released to cause the liver to release glucose
C) Pathways in cellular respiration would switch to using lipids and proteins for ATP production
D) Insulin and glucagon would each be released to quickly return glucose levels to the set point
An animal's inputs of energy and materials would exceed its outputs
A) if the animal is an endotherm, which must always take in more energy because of its high metabolic rate
B) if it is actively foraging for food
C) if it is growing and increasing in mass
D) never; to maintain homeostasis, these energy and material budgets must balance
Which statement best describes the difference in responses of effector B cells (plasma cells) and cytotoxic T cells?
A) B cells confer active immunity; cytotoxic T cells confer passive immunity
B) B cells kill pathogens directly; cytotoxic T cells kill host cells
C) B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells
D) B cells accomplish the cell-mediated response; cytotoxic T cells accomplish the humoral response
Select the one description that is not a feature of the immune system.
A) An antibody has more than one antigen-binding site
B) An antigen can cause different antibodies to be generated
C) A pathogen may present more than one antigen
D) A lymphocyte has receptors for multiple antigens
The first vaccination provides immunity because
A) a localized inflammatory response is initiated
B) the vaccine contains manufactured antibodies against smallpox
C) antigenic determinants in the vaccine activate B cells, which form plasma cells as well as memory cells
D) the vaccine contains antibiotics and other drugs that kill the smallpox virus
The second vaccination is beneficial because it
A) contains plasma cells that survive longer than 4-5 days
B) stimulates production of a higher concentration of antibodies in the bloodstream
C) requires two injections to stimulate antibody formation
D) keeps previously produced plasma cells circulating in the bloodstream
Which figure shows a water-soluble signaling molecule, and what is the evidence for this?
A) Figure A because the signaling molecule results in a response within the cytoplasm
B) Figure A because the signaling molecule does not pass through the phospholipid bilayer
C) Figure B because the signaling molecule enters the cell to bind to the receptor
D) Figure B because the activated receptor is able to enter the nucleus of the cell
In figure A, which molecule represents the receptor protein, and how does it function?
A) Molecule A is the receptor protein because it binds to a plasma membrane surface protein
B) Molecule B is the receptor protein, and molecule A is the ligand that binds it
C) Molecule C is the receptor protein, and it is lipid soluble
D) Molecule D is the receptor protein and once activated initiates a respose
Which of the following correctly represents the events in figure B?
A) In step 1, a signaling molecule binds a G protein-coupled receptor
B) In step 2, the G protein-coupled receptor is activated
C) In step 3, the bound receptor passes through the plasma membrane
D) In step 4, the bound receptor functions as a transcription factor
Which statement correctly describes the function of this neuron?
A) Structure C is produced by glial cells and increases the rate of impulse transmission
B) Structure A releases a neurotransmitter when an action potential is generated
C) Structure B is depolarized when calcium ions are released in this area
D) Structure D initiates the action potential when depolarized
Altruism is putting the well-being of another ahead of one's own. How could it persist in terms of natural selection?
A) Survival of other members of the species will maintain the Hardy-Weinberg equilibrium.
B) It can result in the survival of the recipients of the behavior.
C) This is just one aspect of an important evolutionary principle, survival of the fittest
D) If the altruistic member's behavior is directed toward a close relative, his genes will persist in the population
Why does the insecticide cause uncontrollable twitching in insects?
A) Acetylcholine is released, but the insecticide prevents it from diffusing across the synapse
B) Acetylcholine is released, but the insecticide prevents it from binding to the receptor sites of the postsynaptic neurons
C) The insecticide causes continuous stimulation of the muscles
D) The insecticide prevents acetylcolinesterase from being removed from the synapse
Because pesticides affect humans in a manner similar to that of roaches, it would be valid to conclude that
A) acetylcholinesterase affects the DNA of all animals
B) the mechanism of stimulating skeletal muscle contraction must be similar in humans and roaches
C) pesticides are harmful to roaches but not to humans
D) the terminal end of the axon releases acetylcholine in roaches, but not in humans
Which of these describes a feature that is common to all action potentials (nerve impulses) generated along a neuron?
A) An action potential causes the membrane of the neuron to hyperpolarize and then depolarize
B) An action potential can undergo temporal and spatial summation
C) Action potentials are triggered by a depolarization that reaches a threshold
D) All action potentials move at the same speed along axons
When the action potential reaches the synaptic terminals, which even will occur next?
A) Voltage-gated calcium channels in the membrane open
B) Synaptic vesicles fuse with the membrane
C) The postsynaptic cell produces an action potential
D) Ligand-gated ion channels open, allowing neurotransmitters to enter the synaptic cleft
Why are action potentials usually conducted in only one direction?
A) The nodes of Ranvier can conduct potentials in only one direction
B) The brief refractory period prevents reopening of voltage-gated Na+ channels
C) The axon hillock has a higher membrane potential than the terminals of the axon
D) Voltage-gated channels for both Na+ and K+ open in only one direction
Which of the following conclusions is supported by this graph?
A) Prey size does not affect the number of calories gained per second of handling time by wagtails
B) Wagtails get more calorie per second of handling time with larger flies than with smaller ones
C) Wagtails get more calories per second of handling time with smaller flies than with larger ones
D) Wagtails get more calories per second of handling with 7-mm flies than with either larger or smaller ones
Which of the following experimental approaches might the researcher propose to test the hypothesis that geomagnetic factors (the influence of Earth's magnetic field) play a key role in the ability of salmon to find the proper location along the coast?
A) Trap adult salmon in Ketchikan, Alaska, transport them to a different location on the Alaska Peninsula, Cold Bay, and see if they can return to their home stream
B) Hatch salmon from Ketchikan, Alaska, subject them to geomagnetic characteristics of Cold Bay, Alaska, then release them and see where they eventually return
C) Collect hatchling salmon from Ketchikan, Alaska, release them into the ocean, then see where they eventually return
D) Hatch salmon from Ketchikan, Alaska, raise them in water from Cold Bay, Alaska, then release them and see where they eventually return
What type of behavior would explain the ability of the salmon to return to their home streams?
A) Imprinting, which occurs when a behavior is learned during a critical period in early life
B) Innate behavior, which is developmentally fixed
C) Social learning, which is passed from one individual to another
D) Habituation, which occurs when the same stimulus is applied numerous times
Behaviors are subject to natural selection. Choose the description below that does not support this.
A) Most essential behaviors are the result of some type of learning
B) An individual's reproductive success depends in part on how the behavior is performed
C) Some component of the behavior is genetically inherited but may be modified by learning
D) An individual's genotype influences its behavioral phenotype
Which of the following describes an example of negative feedback?
A) The movement of sodium across a membrane through a transport protein and the movement of potassium in the opposite direction through the same transport protein
B) The pressure of the baby's head against the uterine wall during childbirth that stimulates uterine contractions, causing the greater pressure against the uterine wall, which produces still more contractions
C) A population of bacteria in a petri dish that grows until it has used all its nutrients and then declines
D) A heating system in which the heat is turned off when the temperature exceeds a certain point and is turned on when the temperature falls below a certain point
Pepsinogen is an inactive precursor of pepsin that can be activated by hydrochloric acid. The muscular stomach will could be digested by the active proteolytic enzyme, pepsin. There are several mechanisms, listed below, that will prevent digestion of the stomach wall from happening. Identify the one that will not help prevent this autodigestion.
A) Pepsin is stored and secreted in an inactive form as pepsinogen
B) Mucus lines the inside surface of the stomach and presents a barrier to digestive enzymes
C) Mitosis generates enough new cells to replace the stomach lining every few days
D) Pepsinogen is activated by pepsin and hydrochloric acid
Which of the following represents a failure of a homeostatic mechanism?
A) Activation of the thirst center after profuse sweating
B) Production of insulin after eating a jelly donut
C) Hypothermia after falling into a glacier-fed lake
D) Skin flushing and sweating during exercise
Which of the following is a correct description of ozone in the upper atmosphere?
A) It is composed of O2
B) It limits the amount of radiation available for photosynthesis
C) It is thinning, partially as a result of widespread use of certain chlorine-containing compounds
D) It is a result of widespread burning of fossil fuels
The carrying capacity of a population is defined as
A) the amount of time the parents in the population spend rearing and nurturing their offspring
B) the maximum population size that a certain environment can support at a particular time
C) the amount of vegetation a certain geographic area can support
D) the number of different types of species a biome can support
Characterized by permafrost and few large plants.
A) Temperature grassland
B) Tropical forest
Characterized by epiphytes, a significant canopy, and abundant rainfall
A) Temperature grassland
B) Tropical forest
Characterized by occasional fires, nutrient-rich soil and large grazing animals.
A) Temperature grassland
B) Tropical forest
Characterized by sparse rainfall and extreme daily temperature fluctuations.
A) Temperature grassland
B) Tropical forest
A bacterial colony that exists in an environment displaying ideal conditions will display which of the following growth patterns?
A) Logistic growth
B) Intrinsic growth
C) Demographic growth
D) Exponential growth
Which of the following interspecific interactions represent a form of interaction different from the others?
A) A tick on a human
B) Deer browsing on shrubs
C) A honeybee and apple blossoms
D) A deadly bacterium and hosts
When one species was removed from a tide pool, the species richness became significantly reduced. The removed species was probably
A) the species with the greatest biomass
B) a potent parasite
C) the species with the highest relative abundance
D) a keystone species
Which of the following would not be a density-dependent factor limiting a population's growth?
A) Increased predation by a predator
B) A limited number of available nesting sites
C) A stress syndrome that alters hormone levels
D) A very early fall frost
There are many reasons the human population is increasing so rapidly. Select one factor that does not significantly affect this growth rate.
A) Technology has increased our carrying capacity
B) The death rate has greatly decreased since the Industrial Revolution
C) The age structure of many countries is highly skewed toward younger ages
D) Fertility rates in many developing countries are above the 2.1 children per female replacement level
A Type I survivorship curve is level at first, with a rapid increase in mortality in old age. This type of curve is
A) typical of many invertebrates that produce large numbers of offspring
B) typical of large mammals
C) found most often in r-selected populations, which have a rapid rate of reproduction
D) almost never found in nature
The process in which CO2 in the atmosphere intercepts and absorbs reflected infrared radiation and re-reflects it back to Earth is known as
A) global warming
B) ozone depletion
C) the greenhouse effect
D) biological magnification
A species' specific use of the biotic and abiotic factors in an environment is collectively called the species'
B) trophic level
C) ecological niche
The dominant species in a community is the one that
A) has the greatest number of genes per individual
B) is a the top of the food chain
C) has the largest biomass
D) eats all other members of the community
A fire cleared a large area of forest in Yellowstone National Park in the 1980s. When the first plants pioneered this burned area, this was an example of
A) primary succession
B) secondary succession
C) biological evolution
D) a keystone species
Which of the following is the most probably sequence of events when fertilizer runoff reaches the bay?
A) Submerged vegetation increases, more food for fish and shellfish, fish and shellfish populations increase
B) Phytoplankton population increases, more food for fish and shellfish populations increase
C) Phytoplankton population increases, sunlight blocked to submerged vegetation, submerged vegetation dies, fish and shellfish populations decrease
D) Submerged vegetation decreases, fish and shellfish feed on decaying plants, phytoplankton feed on fish and shellfish, commercial fisheries decline
Which of the following pairs of nutrients would have the greatest effect on growth of phytoplankton?
A) Carbon and hydrogen
B) Oxygen and carbon dioxide
C) Nitrogen and phosphorus
D) Calcium and water
According to this graph of the population growth of fur seals, in what year did the population first reach its carrying capacity?
The formula dN/dt = rmaxN(K-N)/K describes the pattern for the growth for the graph. Which of the following is true concerning the formula and the graph it describes in 1945?
C) The variable K is constantly changing
D) (K - N)/ K = 9,000
Predict the most likely effect on biodiversity when snakeheads are introduced into an aquatic ecosystem.
A) Biodiversity will increase because another species has been added to the ecosystem
B) Biodiversity will decrease because the snakehead will prey on native species
C) Biodiversity will remain the same because local species will prey on the snakeheads and limit their reproduction
D) Biodiversity will decrease because the snakeheads will feel heavily on producer species
Based on the characteristics of the snakehead described, which of the following is most likely to be a productive strategy to reduce the spread of this species?
A) Extend the fishing season for prey fishes
B) Introduce a natural predator to feed on juvenile snakeheads
C) Introduce a fungus that prevents fish eggs from hatching
D) Introduce algae and photosynthetic bacteria to reduce nutrient levels in water
The age-structure data for Nigeria shows that the country has many more individuals under the age of 15 than over the age of 40. What does this imply about the future population of Nigeria?
A) The population will probably remain stable
B) The population will probably decrease
C) The population will probably grow rapidly
D) The number of older people increase rapidly
Based on the age structure of the country, which of the following situations would be most likely over the next 20 years?
A) Strong economic gains stimulated by population growth
B) An increased demand for resources based on population growth
C) A decreased demand for medical services due to the small number of elderly citizens
D) A decline in housing prices based on lack of demand
Which statement best describes energy transfer in a food web?
A) Energy is transferred to consumers, which convert it to nitrogen compounds and use it to synthesize amino acids
B) Energy from producers is converted into oxygen and transferred to consumers
C) Energy from the sun is stored in green plants and transferred to consumers
D) Energy moves from autotrophs to heterotrophs to decomposers, which convert it to a form producers can use again
In ocean kelp forests, kelp perch are preyed upon by kelp bass. In the graph proportional morality rates were calculated for kelp perch as a function of density. The data from the experiment were plotted as shown on this graph. Which statement is a logical conclusion based on the data?
A) Fluctuations in kelp perch density are a result of normal population cycles
B) A negative feedback loop regulates kelp perch population size
C) The equilibrium density for the population of kelp perch can be calculated
D) Higher predation levels lead to healthier kelp perch populations over time