Bio 1012 Exam II Flashcards


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1

2) Light microscopes

A) typically provide more resolution than an electron microscope.

B) work by reflecting electrons off the surface of an object being studied.

C) use light and glass lenses to magnify an image.

D) are generally not used to view bacteria.

Answer: C

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5) Which of the following statements about electron microscopes is true ?

A) Electron microscopes focus electron beams to create a magnified image of an object.

B) Scanning electron microscopes are used to study the details of internal cell structure.

C) Transmission electron microscopes are mainly used to study cell surfaces.

D) Specimens must be sectioned to be viewed under a scanning electron microscope.

Answer: A

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11) As cell size increases, the

A) volume and surface area decrease.

B) volume increases proportionally more than the surface area.

C) surface area increases proportionally more than the volume.

D) ratio of surface area to volume stays the same.

Answer: B

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12) Which of the following cells has the greatest surface-to-volume ratio?

A) bacterium

B) human red blood cell

C) human muscle cell

D) ostrich egg

Answer: A

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17) Archaea are composed of ________ cells.

A) prokaryotic

B) bacterial

C) eukaryotic

D) animal

Answer: A

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24) Which of the following statements about internal membranes in eukaryotic cells is false ?

A) In eukaryotic cells, internal membranes greatly increase a cell's total membrane area.

B) In eukaryotic cells, internal membranes provide an additional area for many metabolic processes to occur.

C) In eukaryotic cells, internal membranes form membranous compartments called organelles.

D) In eukaryotic cells, internal membranes standardize the internal environment of all cellular organelles.

Answer: D

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32) Protein synthesis requires the use of mRNA, which

A) is made in the nucleolus.

B) must be made by the ribosomes.

C) is translated by the ribosomes into the amino acid sequences of proteins.

D) carries the message to the nucleus to synthesize new DNA during cell division.

Answer: C

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35) The endomembrane system includes all of the following organelles except the

A) plasma membrane.

B) endoplasmic reticulum.

C) peroxisome.

D) Golgi apparatus.

Answer: C

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36) An immune system cell called the plasma cell produces thousands of antibodies per second for release into the body. What type of intracellular structure would you expect to be very prominent within the cell?

A) nucleus

B) endoplasmic reticulum

C) peroxisome

D) microtubules

Answer: B

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37) Smooth endoplasmic reticulum

A) stores calcium ions in muscle cells.

B) is the major site of carbohydrate synthesis in eukaryotic cells.

C) produces proteins for cell membranes.

D) helps assemble ribosomes for protein synthesis.

Answer: A

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39) Secretory proteins are

A) produced by ribosomes on the smooth endoplasmic reticulum.

B) chemically modified in the nucleus.

C) produced by the cell for internal use.

D) released from the cell through the plasma membrane.

Answer: D

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45) Tay-Sachs disease results from the malfunction of

A) mitochondria.

B) lysosomes.

C) endoplasmic reticulum.

D) nucleoli.

Answer: B

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46) Tay-Sachs disease

A) causes an accumulation of lipids in brain cells.

B) involves damage to liver cells.

C) is due to the absence of an enzyme that digests polysaccharides.

D) prevents the breakdown of glycogen.

Answer: A

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47) Which of the following statements about the functions of a plant cell central vacuole is false ?

A) The central vacuole of a plant cell may help increase the size of cells by absorbing water.

B) The central vacuole of a plant cell may store waste products.

C) The central vacuole of a plant cell may digest chemicals for recycling.

D) The central vacuole of a plant cell may store poisons.

Answer: C

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56) The stroma is the

A) thick fluid enclosed by the inner chloroplast membrane.

B) watery fluid enclosed by the inner membrane of a mitochondrion.

C) space between the inner and outer membranes of a chloroplast.

D) space between the inner and outer membranes of a mitochondrion.

Answer: A

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57) Mitochondria differ from chloroplasts in that mitochondria

A) convert light energy from the sun to chemical energy, whereas chloroplasts convert one form of chemical energy to another.

B) contain three different membrane-bound compartments, whereas chloroplasts contain two.

C) contain membrane folds called cristae, whereas chloroplasts contain disk-like vesicles in stacks called grana.

D) are not found in plants, whereas chloroplasts are not found in animals.

Answer: C

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62) Intermediate filaments

A) guide the movements of chromosomes.

B) surround the nucleus.

C) guide the movements of organelles.

D) support the inner mitochondrial membrane.

Answer: B

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63) A drug that interferes with microtubule formation is likely to completely disrupt

A) the amoeboid motion of a cell.

B) the function of lysosomes.

C) contraction of muscle cells.

D) the movements of sperm cells.

Answer: D

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64) Cilia differ from flagella in that

A) cilia contain nine microtubule doublets surrounding a central pair of microtubules, whereas flagella contain only nine microtubule doublets.

B) the protein filaments of cilia are "naked," whereas those of flagella are wrapped in an extension of the cell membrane.

C) cilia are typically more numerous and shorter than flagella.

D) cilia are anchored only in the proteins of the cell membrane, whereas flagella are anchored in a special structure called the basal body.

Answer: C

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65) A basal body is

A) composed of nine microtubule triplets surrounding a central pair of microtubules.

B) similar in structure to centrioles.

C) composed of nine microtubule doublets surrounding a central pair of microtubules.

D) identical in structure to cilia.

Answer: B

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66) Dynein feet

A) are present in cilia but not in flagella.

B) are knobs of carbohydrate that are essential to the movement of cilia and flagella.

C) are found on microtubules in cilia and flagella and cause movement by grabbing and pulling at adjacent microtubule doublets.

D) are the anchoring proteins in basal bodies.

Answer: C

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4) The cholesterol associated with animal cell membranes

A) is attached to membrane proteins and extends into the watery environment surrounding the cell.

B) helps to keep phospholipids from being too close to one another.

C) is an abnormality resulting from a diet high in cholesterol.

D) helps solidify the membranes when the room temperature is below freezing.

Answer: B

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8) Which of the following statements regarding membrane protein function is false ?

A) Membrane proteins serve as enzymes.

B) Membrane proteins act as receptors to molecules like hormones.

C) Membrane proteins form junctions between cells.

D) Membrane proteins transfer genetic information to the cytoplasm.

Answer: D

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12) Which characteristic promoted the utilization of lipids as the first cell membrane?

A) spontaneous degradation of the intracellular environment

B) self-assembly into a simple membrane

C) ability to form an impermeable membrane

D) formation of a semi-solid membrane

Answer: B

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14) Small, nonpolar, hydrophobic molecules such as fatty acids

A) easily pass through a membrane's lipid bilayer.

B) very slowly diffuse through a membrane's lipid bilayer.

C) require transport proteins to pass through a membrane's lipid bilayer.

D) are actively transported across cell membranes.

Answer: A

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22) Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment

A) is isotonic to the protozoan.

B) is hypotonic to the protozoan.

C) contains a higher concentration of solutes than the protozoan.

D) is hypertonic to the protozoan.

Answer: B

27

26) In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is ________ relative to the solution in the beaker.

A) isotonic

B) hypotonic

C) hypertonic

D) hydrophilic

Answer: B

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30) Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.

A) energy and transport proteins; down

B) transport proteins; down

C) energy and transport proteins; against

D) transport proteins; against

Answer: B

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35) Which of the following is a typical feature of an ATP-driven active transport mechanism?

A) The transport protein must cross to the correct side of the membrane before the solute can bind to it.

B) The transport protein is irreversibly phosphorylated as transport takes place.

C) The transport protein catalyzes the conversion of ADP to ATP.

D) The solute moves against the concentration gradient.

Answer: D

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39) Phagocytosis is to eating as pinocytosis is to

A) osmosis.

B) drinking.

C) chewing.

D) lysis.

Answer: B

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44) Which of the following statements regarding thermodynamics is false ?

A) Thermodynamics is the study of energy transformations that occur in a collection of matter.

B) A single cell or the planet Earth could be a thermodynamic system.

C) An open system exchanges both energy and matter with its surroundings.

D) An automobile engine is a closed system because it does not exchange energy and matter with its surroundings.

Answer: D

32

48) Living systems

A) violate the first law of thermodynamics.

B) violate the second law of thermodynamics.

C) decrease their entropy while increasing the entropy of the universe.

D) are examples of a closed system.

ANswer: C

33

49) Which of the following processes is endergonic?

A) the burning of wood

B) the synthesis of glucose from carbon dioxide and water

C) the breakdown of glucose

D) cellular respiration

Answer: B

34

57) An energy barrier

A) is the amount of energy that must be produced by the reactants to end a chemical reaction.

B) is higher than the activation energy of a reaction.

C) prevents the spontaneous breakdown of molecules in the cell.

D) can only be overcome with the use of enzymes.

ANswer: c

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69) How does inhibition of an enzyme-catalyzed reaction by a competitive inhibitor differ from inhibition by a noncompetitive inhibitor?

A) Competitive inhibitors interfere with the enzyme; noncompetitive inhibitors interfere with the reactants.

B) Competitive inhibitors bind to the enzyme reversibly; noncompetitive inhibitors bind to it irreversibly.

C) Competitive inhibitors change the enzyme's tertiary structure; noncompetitive inhibitors cause polypeptide subunits to dissociate.

D) Competitive inhibitors bind to the active site of the enzyme; noncompetitive inhibitors bind to a different site.

ANswer: D

36

71) Inhibition of an enzyme is irreversible when

A) a competitive inhibitor is involved.

B) a noncompetitive inhibitor is involved.

C) the shape of the enzyme is changed.

D) covalent bonds form between inhibitor and enzyme.

Answer: D