The smallest unit of life is the:
What are the attributes of life?
Response to environment
What are the three domains of life?
True or false: Evolution works on individuals, not populations.
True or false: A hypothesis must be testable.
What are the four main elements life is made up of?
Oxygen, carbon, hydrogen, and nitrogen
Atomic number = the number of _____ an element has
An isotope has the same number of ______ and a different number of ______ as the original element
What is the difference between ionic and covalent bonds?
Ionic bonds involve the giving and taking of electrons, while covalent bonds involve the sharing of electrons.
True or false: Ionic bonds are considered weak bonds in biology.
What are the four main properties of water?
Expands when frozen
True or false: Water is nonpolar
What is the specific heat of water in calories?
Is water good at dissolving fats?
What is the formula for pH?
How many valence electrons does carbon have?
What is an isomer?
A molecule with the same formula but a different structure
List the names and formulas of three of the seven functional groups:
The options are carboxyl (COOH), amine (NH2), sulfhydryl (SH), phosphate (PO4), methyl (CH3), hydroxyl (OH), and carbonyl (CO)
Name the formula of glucose:
Sugars form what distinctive shape?
Name three potential functions of a protein:
Describe the four levels of protein structure.
1) Amino acid sequence
2) Hydrogen bonding (a helixes and B pleated sheets)
3) Interactions between R groups (various types of bonding)
4) Interactions between multiple proteins
Name the type of bonds that hold amino acids, nucleic acids, carbohydrates, and lipids together.
1) Peptide bonds 2) Phosphodiester bonds 3) Glycosidic bonds 4) Ester bonds
What are the purines and pyrimidines, and which one has two rings?
Pyrimidines: cytosine, thymine, uracil
Purines: adenine, guanine
Purines have two rings
True or false: DNA is made of a sugar known as deoxyribose
Eukaryotic cells can range in size from _____ - _____ microns, and the smaller prokaryotic cells range from ____-____ microns.
True or false: Prokaryotes have membrane-bound organelles.
Name four common parts of a cell and their function:
Nucleus: Contains genetic material for reproduction.
Mitochondria: Used to produce energy
Golgi complex: Packages proteins that are to be sent outside the cell
Smooth ER: Manufactures steroids and fats, acts in liver function
Rough ER: Manufactures proteins that are to be sent outside the cell
Free ribosome: Manufactures proteins that remain in the cell
Lysosome: Digests unwanted parts of cell and intruders
Extracellular matrix: Allows cells to communicate and structure themselves with other cells
What is the fluid inside a cell called?
Name 3 organelles plants have that animals don't:
1) Cell wall
2) Central vacuole
True or false: The cell's membrane is called a methylipid membrane.
False (it is a phospholipid membrane)
Sort these forms of transportation into active and passive.
Describe one of the three forms of endocytosis:
phagocytosis - Cell engulfs a solid particle
pinocytosis - Small particles are drawn into the cell and stored within vesicles
receptor-mediated endocytosis - specific particles are drawn in
True or false: The lipids in the plasma membrane have hydrophobic heads and hydrophilic tails
Osmosis proceeds from a _______ concentration of substrate to a _______ concentration.
Describe two key features of anabolic and catabolic reactions.
Anabolic: Builds molecules, requires energy
Catabolic: Destroys molecules, gives off energy
What are the First and Second Laws of Thermodynamics?
1) energy cannot be created or destroyed
2) entropy in the universe always increase
What is the full name of ATP?
Which of the following is true about enzymes?
a) They can only be used once
b) They have the power to turn any reactant into their product
c) They lower the activation energy of a reaction
d) They raise the activation energy of a reaction
Which of the following can affect the rate of an enzymatic reaction?
c) Substrate concentration
d) All of the above
Oxidation implies __________, while reduction implies __________
loss of electrons, gain of electrons
Glycolysis requires an input of __ ATP, and produces a total of ____ ATP.
Where do glycolysis, the Krebs cycle, and oxidative phosphorylation take place?
Glycolysis - cytoplasm
Krebs Cycle - matrix of the mitochondria
Oxidative phosphorylation - from the matrix into the intermembrane space
True or false: The electron transport chain produces 34 ATP.
How many NADH and FADH2 are produced over the course of cellular respiration, and what are they used for?
8 NADH, 2 FADH2. They are oxidized to fuel the electron transport chain.
_______, an organelle found in plant cells, consist of a double membrane and an internal space called the ______, filled with stacks of ________ known as _______.
Chloroplasts, stroma, thylakoids, granae
True or false: Chlorophyll is made of a hydrocarbon head and a porphyrin tail.
False. It's the other way around
When the light reactions of photosynthesis occur, _______ are passed from _________, containing ______, to __________, which contains ________.
electrons, photosystem II, P680, photosystem I, P700
True or false: Paracrine signaling occurs over long distances.
Name the three stages of cell communication that occur once a signal is received.
Name and describe the three major types of receptors.
G-protein coupled receptors. They are made up of a single protein that crosses the membrane seven times. That protein couples with a G-protein that binds GDP. When the ligand binds, the G-protein grabs a GTP instead and detaches, starting a cascade
Receptor tyrosine kinases. These phosphorylate, hence their name. When a signal appears, they form dimers. Then a phosphorylation cascade eventually transduces the signal to its relevant location.
Ion-channel receptors. These channels let only particular ions into the cell.
What is the molecule used for signaling called?
True or false: The original signals sent never directly enter the target cell.
False: Some signals, like testosterone, will enter the cell.
What are the five phases of the cell cycle and a brief description of each?
1) Interphase - cell is doing normal cell things, including duplicating chromosomes
2) Prophase - chromatin begins to condense into coherent chromosomes
3) Metaphase - chromosomes "line up" along the center of the nucleus
4) Anaphase - sister chromatids are pulled apart by microtubules called the mitotic spindle
5) Telophase - chromosomes separate fully and cytokinesis begins
Homologous chromosomes are ______, while sister chromatids are ______.
Different chromosomes inherited from different parents, copies of the same chromosome ready for mitosis or meiosis
Define the terms kinetochore, centromere, centrosome, and centriole
Kinetochore - where the spindle fiber attaches to a chromosome
Centromere - the larger area that encompasses the kinetochore in the center of the chromosome
Centrosome - the other end that the microtubules originate from
Centriole - a part of the centrosome that functions in microtubule production
True or false: All microtubules attach to a kinetochore during mitosis.
False: There are non-kinetochore microtubules
a: Genetically identical daughter cells
b: Genetically varied daughter cells
c: It depends on the type of mitosis
d: None of the above
a: Genetically identical daughter cells
b: Genetically varied daughter cells
c: It depends on the type of meiosis
d: None of the above
If a cell has 36 chromosomes during G1, how many chromosomes will its gametes have? What is 2n and n?
Its gametes will have 18. 2n is 36 and n is 18.
At what stage of meiosis do homologous chromosomes separate? At what stage do sister chromatids separate?
What are three major sources of genetic variation? Explain
independent assortment of chromosomes - chromosomes can line up on the metaphase plate in any arrangement
crossing over - bits and pieces of chromosomes are exchanged
random fertilization - who knows what gamete you'll get?
True or false: Meiosis occurs naturally in all body cells.
False. It only occurs to produce gametes.
Describe the Law of Segregation and the Law of Independent Assortment, and when in meiosis they occur.
Law of Segregation: Each pair of alleles splits up when the gametes are formed. Occurs during Anaphase 1
Law of Independent Assortment: Alleles line up on the metaphase plate regardless of which parent they came from. Occurs during Metaphase 1
What two organisms are used in a test cross, what is its purpose, and how is that purpose achieved?
A dominant-phenotype, unknown-genotype plant and a known homozygous recessive plant are used. The purpose is to identify the genotype of the unknown plant. If the unknown plant has any recessive alleles, there will be some offspring that get two recessive alleles and thus express a recessive phenotype. If not, every single offspring will be dominant.
Which scientist laid down the foundation for genetics, and what experiments did he perform?
Gregor Mendel, who crossed true-breeding pea plants to observe the resulting offspring. From the monohybrid cross he established the Law of Segregation, and the dihybrid cross established the Law of Independent Assortment
P1: the parent generation of plants
F1: The filial generation
F2: The "Grandchildren" of the original plants
Dominant: An allele that is expressed with either 1 or 2 copies
Recessive: An allele that needs 2 copies to be expressed
Homozygous: Having two of the the same allele
Heterozygous: Having different alleles
What are some examples of recessively inherited disorders? Dominantly inherited?
Tay-Sachs, sickle cell anemia, cystic fibrosis
What is a centimorgan?
A unit that measures distance between genes on a chromosome based on genetic recombination frequency. A centimorgan represents a 1% chance of recombination between two genes.
What is aneuploidy? What is polyploidy? What are some examples?
Aneuploidy is when a single chromosome is duplicated or missing. Down Syndrome (trisomy 21) is an example. Polyploidy is when a whole set of chromosomes has been duplicated or is missing. An example is certain plants which naturally are polyploid, like many ferns and grasses.
Name four common chromosomal alterations and explain.
deletion - part of a chromosome is lost
duplication - part of a chromosome appears twice
inversion - a piece of a chromosome is put in backwards
translocation - parts of a chromosome are swapped with another part of a chromosome
What is notable about Prader-Willi and Angelman syndrome?
They are caused by the same chromosomal abnormality, but Prader-Willi occurs if the deletion is on the paternally inherited chromosome and Angelman occurs if the deletion is on the the maternally inherited chromosome, due to imprinting.
What is the formula for how many unique gametes a cell can produce?
2n where n is the number of chromosomes.
Write an overview of the process of DNA replication in bacteria:
At first the two strands are attached. Then helicase unwinds the double helix, creating a replication bubble and two replication forks. Single-stranded binding proteins keep the strands separate, and topoisomerase releases the tension between the two as they unwind.
The two separate strands are known as the leading and lagging strand: The leading strand can be replicated directly by DNA polymerase III, while the lagging strand is split into fragments called Okazaki fragments which are synthesized in the opposite direction by DNA polymerase I. This is because DNA polymerases can only function in the 5 (phosphate) to 3 (hydroxyl) direction. Primase functions to set up a primer for the DNA polymerase to work from. On the lagging strand, ligase joins the Okazaki fragments together.
Describe the Griffith and Hershey-Chase experiments.
Griffith studied pneumonia in mice. There were two varieties of bacteria, R, which was harmless, and S, which was deadly. He combined heat-killed S bacteria with harmless R bacteria and the R bacteria picked up some substance (he didn't know which) that transformed it to become deadly.
Hershey and Chase worked with E. coli and T2 phages. They prepared phages with radioactively labelled DNA and proteins. They found that, after the phages attacked, E. coli had radioactive DNA but not proteins, proving that the material that transformed it was DNA.
What are Chargaff's rules, and why (was it later discovered) do they hold?
That A = T and C = G. This is true because A and G are the same type (purines) and both have two rings, and C and T are both pyrimidines that have one ring. The two-ring molecules couldn't fit together, and the one-ring molecules together would be too short.
Who established the structure of DNA, and what is that structure?
Watson, Crick and Franklin performed x-ray crystallography to find DNA is a double helix.
What is a nucleotide made up of?
Whatever base it has, a deoxyribose sugar, and a phosphate group
A protein is about to be made. The ___________ affixes to the ______, which enters at the _____ site. Next, whichever one of the 64 ________ is read and ___________.
large ribosomal subunit, RNA, A. Codons, translated
What are some modifications made in RNA before it is used?
1) Addition of a 5' cap made of guanine
2) Addition of a poly A tail made of adenines
3) Introns are removed by spliceosomes
Explain the reading frame.
It ensures only three amino acids are read at the same time and they actually belong to one codon rather than being different..
What are the start and stop codons?
AUG is start, UAG, UAA, and UGA are stop
What are the three steps of transcription and what happens during each?
1) Initiation (transcription initiation complex forms at the promoter)
2) Elongation (RNA is made)
3) Termination (transcription enzymes reach stop codon and separate)
Describe the trip and Lac operons.
Trip operon refers to E. coli, which sometimes needs to synthesis tryptophan for its use. It is repressible, meaning it is normally on and, if tryptophan is present, its presence will turn it off. It has a repressor which is made inactive and tryptophan will bind to it and activate it in a form of feedback inhibition.
Lac operon is also present in E. coli. It is inducible, meaning it is normally off. The presence of lactose will turn off the repressor and allow the bacteria to digest lactose.
In what configuration is chromatin usually stored?
30 nm fibers
True or false: Acetylation discourages transcription.
False; it actually causes chromatin to spread out and makes it easier
What are proximal and distal control elements?
Proximal elements are near the promoter and are sometimes classified as part of it. Distal elements are farther away and are divided into silencers and enhancers.
What is feedback inhibition?
When the buildup of a product causes regulation of the enzyme making the product so that the product is no longer made.
What is a capsid? What is a capsomere?
The virus's protein coat is called a capsid, and it is made up of capsomeres.
What are the four major types of viruses, along with a brief description?
1) Helical - tube-shaped, about 15-19 nm wide, 300-500 in length
2) adenovirus - icosahedral
3) Envelope virus - has a distinct coat
4) Phage - larger, has head and tail
Describe the lytic and lysogenic cell cycles, and name a virus that functions in each way.
Lytic: Virus enters a cell, uses it to manufacture new viruses, explodes and kills it. Common cold is an example
Lysogenic: Virus enters a cell, incorporates its genome into the DNA and waits for the opportune time to reproduce, leaving the cell alive. HIV is an example
Viruses are generally how big?
What four types of genetic material can a virus have?
Either 1 or 2-stranded DNA, or 1 or 2-stranded RNA
What is a plasmid?
A circular DNA molecule separate from the rest of the cell's DNA, common in bacteria and useful for cloning.
What are restriction enzymes?
Enzymes that cut DNA at a certain pre-programmed point.
What is PCR, what does it stand for, and what are its steps?
A technique by which DNA can be cloned, also known as Polymerase Chain Reaction. A DNA molecule is heated so that it denatures and its strands separate. Annealing occurs (attachment of primers to the relevant section of DNA). Then enzymes are used to make new DNA off the strands of the previous DNA, and the process is repeated until the scientists have enough DNA to work with.
True or false: During gel electrophoresis, larger molecules end up farther away from the source.
True or false: When performing animal cloning, one female provides the egg, a different one hosts the zygote in her womb, and a different one provides DNA.
What percent of human DNA is non-coding repetitive?
What is the difference between transposons and retrotransposons?
Transposons can move by themselves and insert into a different part of DNA, while retrotransposons require RNA made of them and then copied back into DNA.
What is alternative splicing?
When RNA is made, different sections are used as eons, creating different RNA and different proteins.