ap biology midterm exam review...

AP BIOLOGY Midterm Exam Review

2009-2010

Name: ______________________________

Section 1 Biochemistry MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers

the question.

1) About 25 of the 92 natural elements are known to be essential to life.

Which four of these 25 elements make up approximately 96% of living

matter?

A) oxygen, hydrogen, calcium, sodium

B) carbon, sodium, chlorine, nitrogen

C) carbon, oxygen, sulfur, calcium

D) carbon, sulfur, phosphorus, hydrogen

E) carbon, hydrogen, nitrogen, oxygen

2) A covalent bond is likely to be polar when

A) the two atoms sharing electrons are different elements.

B) one of the atoms sharing electrons is much more electronegative

than the other atom.

C) the two atoms sharing electrons are of the same element.

D) the two atoms sharing electrons are equally electronegative.

E) it is between two atoms that are both very strong electron

acceptors.

3) Which of the following explains most specifically the attraction of water

molecules to one another?

A) polar covalent bond

B) ionic bond

C) hydrogen bond

D) hydrophobic interaction

E) nonpolar covalent bond

4) Which of the following best describes chemical equilibrium?

A) Reactions stop only when all reactants have been converted to

products.

B) Forward and reverse reactions have stopped so that the

concentration of the reactants equals the concentration of the

products.

C) Concentrations of products are higher than the concentrations of

the reactants.

D) Forward and reverse reactions continue with no effect on the

concentrations of the reactants and products.

E) There are equal concentrations of reactants and products, and the

reactions have stopped.

5) A group of molecular biologists is trying to synthesize a new artificial

compound to mimic the effects of a known hormone that influences

sexual behavior. They have turned to you for advice. Which of the

following compounds is most likely to mimic the effects of the

hormone?

A) a compound with the same three-dimensional shape as part of the

hormone

B) a compound with the same number of carbon atoms as the

hormone

C) a compound with the same molecular mass (measured in daltons)

as the hormone

D) a compound with the same number of hydrogen and nitrogen

atoms as the hormone

E) a compound with the same number of orbital electrons as the

hormone

6) Which of the following statements correctly defines a kilocalorie?

A) the amount of heat required to raise the temperature of 1 g of

water by 1°C

B) the amount of heat required to raise the temperature of 1 kg of

water by 1°F

C) the amount of heat required to raise the temperature of 1,000 g of

water by 1°F

D) the amount of heat required to raise the temperature of 1 kg of

water by 1°C

E) the amount of heat required to raise the temperature of 1 g of

water by 1°F

7) At what temperature is water at its densest?

A) 4°C

B) 212°C

C) 100°C

D) 32°C

E) 0°C

The following question is based on Figure 3.1: solute molecule surrounded by a hydration shell of water.

Figure 3.1

8) Based on your knowledge of the polarity of water molecules, the solute

molecule is most likely

A) hydrophobic.

B) positively charged.

C) nonpolar.

D) negatively charged.

E) without charge.

9) Which of the following people used this apparatus to study formation of

organic compounds?

A) August Kekulé

B) Friedrich Wohler

C) Hermann Kolbe

D) Jakob Berzelius

E) Stanley Miller

10) Which of the pairs of molecular structures shown below depict

enantiomers (enantiomeric forms) of the same molecule?

A)

B)

C)

D)

E)

11) Which of the following contains nitrogen in addition to carbon, oxygen,

and hydrogen?

A) an alcohol such as ethanol

B) a steroid such as testosterone

C) an amino acid such as glycine

D) a monosaccharide such as glucose

E) a hydrocarbon such as benzene

12) For this pair of items, choose the option that best describes their

relationship.

(A) The number of alpha glucose 1-4 linkages in cellulose (B) The number of alpha glucose 1-4 linkages in starch

A) Item (A) is greater than item (B).

B) Item (A) is exactly or very approximately equal to item (B).

C) Item (A) is less than item (B).

D) Item (A) may stand in more than one of the above relations to item

(B).


relationship.

(A) The number of cis double bonds in saturated fatty acids (B) The number of cis double bonds in unsaturated fatty acids

A) Item (A) is exactly or very approximately equal to item (B).

B) Item (A) is less than item (B).

C) Item (A) is greater than item (B).


(B).


relationship.

(A) The probability that amino acids with nonpolar side chains are

hydrophobic. (B) The probability that amino acids with side chains containing a

carboxyl group are hydrophobic.

A) Item (A) is less than item (B).

B) Item (A) may stand in more than one of the above relations to item

(B).

C) Item (A) is greater than item (B).

D) Item (A) is exactly or very approximately equal to item (B).


relationship.

(A) The number of purines in the DNA strand 5'-AAGAGGAGAAA-3' (B) The number of pyrimidines in the DNA strand 5'-AAGAGGAGAAA-3'

A) Item (A) is greater than item (B).

B) Item (A) is exactly or very approximately equal to item (B).

C) Item (A) is less than item (B).


(B).

16) Which of the following is not a polymer?

A) glucose

B) cellulose

C) chitin

D) DNA

E) starch

Figure 5.4

17) What is the structure shown in Figure 5.4?

A) phospholipid molecule

B) starch molecule

C) protein molecule

D) cellulose molecule

E) steroid molecule

18) What maintains the secondary structure of a protein?

A) peptide bonds

B) phosphodiester bonds

C) disulfide bonds

D) hydrogen bonds

E) ionic bonds

19) At which level of protein structure are interactions between the side

chains (R groups) most important?

A) primary

B) secondary

C) quaternary

D) tertiary

E) all of the above

The following questions are based on the 15 molecules illustrated in Figure 5.8. Each molecule may be used

once, more than once, or not at all.

Figure 5.8

20) Which molecule has hydrophilic and hydrophobic properties and

would be found in plasma membranes?

A) 12 B) 1 C) 5 D) 6 E) 14

21) Which of the following molecules is a purine type of nitrogenous base?

A) 3 B) 2 C) 12 D) 5 E) 13

22) Which of the following molecules act as building blocks (monomers) of

polypeptides?

A) 2, 7, and 8

B) 11, 12, and 13

C) 1, 4, and 6

D) 12, 13, and 15

E) 7, 8, and 13

23) How can one increase the rate of a chemical reaction?

A) Cool the reactants.

B) Add a catalyst.

C) Increase the entropy of the reactants.

D) Increase the activation energy needed.

E) Decrease the concentration of the reactants.

24) During a laboratory experiment, you discover that an enzyme-catalyzed

reaction has a △G of -20 kcal/mol. If you double the amount of enzyme

in the reaction, what will be the △G for the new reaction?

A) -40 kcal/mol

B) -20 kcal/mol

C) +20 kcal/mol

D)

+40 kcal/mol

E) 0 kcal/mol

The next questions are based on the following information.

A series of enzymes catalyze the reaction X → Y → Z → A. Product A binds to the enzyme that

converts X to Y at a position remote from its active site. This binding decreases the activity of the

enzyme.

25) What is substance X?

A) a coenzyme

B) an intermediate

C) an allosteric inhibitor

D) the product

E) a substrate

26) Substance A functions as

A) the substrate.

B) an intermediate.

C) a competitive inhibitor.

D) a coenzyme.

E)

an allosteric inhibitor.

Section 2 Evolution

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers

the question.

27) Which of the following statements is an inference of natural selection?

A) Natural populations tend to reproduce to their full biological

potential.

B) Subsequent generations of a population should have greater

proportions of individuals that possess traits better suited for

success in unchanging environments.

C) An individual organism undergoes evolution over the course of its

lifetime.

D) Habitats do not generally have unlimited resources.

E) Some of the variation that exists among individuals in a

population is genetic.

28) In a hypothetical environment, fishes called pike-cichlids are visual

predators of algae-eating fish (i.e., they locate their prey by sight). If a

population of algae-eaters experiences predation pressure from pike-cichlids, which of the following should least likely be observed in the

algae-eater population over the course of many generations?

A) Selection for algae-eaters that become sexually mature at smaller

overall body sizes

B) Selection for algae-eaters that are faster swimmers

C) Selection for drab coloration of the algae-eaters

D) Selection for nocturnal algae-eaters (active only at night)

E) Selection for larger female algae-eaters, bearing broods composed

of more, and larger, young

29) If, on average, 46% of the loci in a species' gene pool are heterozygous,

then the average homozygosity of the species should be

A) 46%

B) 54%

C) 92%

D) 23%

E) There is not enough information to say.

30) Which of these is the smallest unit upon which natural selection directly

acts?

A) an individual's genome

B) an individual's genotype

C) a population's gene frequency

D) a species' gene frequency

E) an individual's phenotype

Use the following information to answer the questions below. A large population of laboratory animals has been allowed to breed randomly for a number of

generations. After several generations, 25% of the animals display a recessive trait (aa), the same

percentage as at the beginning of the breeding program. The rest of the animals show the

dominant phenotype, with heterozygotes indistinguishable from the homozygous dominants.

31) What is the most reasonable conclusion that can be drawn from the fact

that the frequency of the recessive trait (aa) has not changed over time?

A) The population is undergoing genetic drift.

B) The genotype AA is lethal.

C) There has been sexual selection favoring allele a.

D) The two phenotypes are about equally adaptive under laboratory

conditions.

E) There has been a high rate of mutation of allele A to allele a.

32) What proportion of the population is probably heterozygous (Aa) for

this trait?

A) 0.75 B) 0.05 C) 1.00 D) 0.25 E) 0.50

33) In a Hardy-Weinberg population with two alleles, A and a, that are in

equilibrium, the frequency of allele a is 0.1. What is the percentage of the

population that is heterozygous for this allele?

A) 18 B) 10 C) 81 D) 90 E) 49

34) Arrange the following from most general (i.e., most inclusive) to most

specific (i.e., least inclusive): 1. Natural selection 2. Microevolution 3. Intrasexual selection 4. Evolution 5. Sexual selection

A) 1, 4, 2, 5, 3

B) 4, 1, 2, 3, 5

C) 1, 2, 4, 5, 3

D) 4, 2, 1, 3, 5

E) 4, 2, 1, 5, 3

35) The biological species concept is inadequate for grouping

A) asexual organisms.

B) animals that migrate.

C) sympatric populations.

D) parasites.

E) plants.

36) A hybrid zone is properly defined as

A) an area where mating occurs between members of two closely

related species, producing viable offspring.

B) a zone that features a gradual change in species composition

where two neighboring ecosystems border each other.

C) a zone that includes the intermediate portion of a cline.

D) an area where members of two closely related species intermingle,

but experience no gene flow.

E) an area where two closely related species' ranges overlap.

37) The most likely explanation for the high rate of sympatric speciation

that apparently existed among the cichlids of Lake Victoria in the past is

A) sexual selection.

B) introduction of a new predator.

C) pollution.

D) habitat differentiation.

E) polyploidy.

38) Which of the following is the correct sequence of these events in the

origin of life? I. formation of protobionts II. synthesis of organic monomers III. synthesis of organic polymers IV. formation of DNA-based genetic systems

A) IV, III, I, II

B) I, II, III, IV

C) III, II, I, IV

D) I, III, II, IV

E) II, III, I, IV

39) Approximately how far back in time does the fossil record extend?

A) 6,000 years

B) 3,500,000 years

C) 3,500,000,000 years

D) 5,000,000,000,000 years

E) 6,000,000 years

40) What is thought to be the correct sequence of these events, from earliest

to most recent, in the evolution of life on Earth? 1. origin of mitochondria 2. origin of multicellular eukaryotes 3. origin of chloroplasts 4. origin of cyanobacteria 5. origin of fungal-plant symbioses

A) 4, 1, 2, 3, 5

B) 4, 3, 2, 1, 5

C) 4, 1, 3, 2, 5

D) 4, 3, 1, 5, 2

E) 3, 4, 1, 2, 5

41) A phylogenetic tree that is "rooted" is one

A) with very few branch points.

B) that extends back to the origin of life on Earth.

C) that illustrates the rampant gene swapping that occurred early in

life's history.

D) that indicates our uncertainty about the evolutionary relationships

of the taxa depicted on the tree.

E) at whose base is located the common ancestor of all taxa depicted

on that tree.

42) A taxon, all of whose members have the same common ancestor, is

A) polyphyletic. B) paraphyletic. C) monophyletic.

43) Phylogenetic hypotheses (such as those represented by phylogenetic

trees) are strongest when

A) each clade is defined by a single derived character.

B) they are based on a single DNA sequence that seems to be a shared

derived sequence.

C) they are supported by more than one kind of evidence, such as

when fossil evidence corroborates molecular evidence.

D) they are based on amino acid sequences from homologous

proteins, as long as the genes that code for such proteins contain

no introns.

E) they are accepted by the foremost authorities in the field,

especially if they have won Nobel Prizes.

The following questions refer to the table below, which compares the % sequence homology of

four different parts (2 introns and 2 exons) of a gene that is found in five different eukaryotic

species. Each part is numbered to indicate its distance from the promoter (e.g., Intron I is that

closest to the promoter). The data reported for Species A were obtained by comparing DNA from

one member of species A to another member of Species A. % Sequence Homology Species Intron I Exon I Intron VI Exon V A 100% 100% 100% 100% B 98% 99% 82% 96% C 98% 99% 89% 96% D 99% 99% 92% 97% E 98% 99% 80% 94%

44) Based on the tabular data, and assuming that time advances vertically,

which cladogram (a type of phylogenetic tree) is the most likely

depiction of the evolutionary relationships among these five species?

A)

B)

C)

D)

The following questions refer to this phylogenetic tree, depicting the origins of life and of the three domains.

Horizontal lines indicate instances of gene or genome transfer.

45) A large proportion of archaeans are "extremophiles," so called because

they inhabit extreme environments with high acidity and/or high

temperature. Such environments are thought to have been much more

common on the primitive Earth. Thus, modern extremophiles survive

only in places that their ancestors became adapted to long ago. Which of

these is, consequently, a valid statement about modern extremophiles,

assuming that their habitats have remained relatively unchanged?

A) Among themselves, they should share relatively few ancestral

traits, especially those that enabled ancestral forms to adapt to

extreme conditions.

B) They should contain genes that originated in eukaryotes that are

the hosts for numerous species of bacteria.

C) On a phylogenetic tree whose branch lengths are proportional to

amount of genetic change, the branches of the extremophiles

should be shorter, relative to branches of the non-extremophilic

archaeans.

D) They should currently be undergoing a high level of horizontal

gene transfer with non-extremophilic archaeans.

Part 3 Ecology


the question.

46) Which of the following levels of organization is arranged in the correct

sequence from most to least inclusive?

A) community, ecosystem, individual, population

B) ecosystem, community, population, individual

C) individual, community, population, ecosystem

D) population, ecosystem, individual, community

E) individual, population, community, ecosystem

47) Landscape ecology is best described as the study of

A) how the structure and function of species enable them to meet the

challenges of their environment.

B) the factors controlling the exchanges of energy, materials, and

organisms among ecosystem patches.

C) the interactions between the different species that inhabit and

ecosystem.

D) what factors affect the structure and size of a population over time.

E) the flow of energy and materials between the biotic and abiotic

components of an ecosystem.

48) Which of the following environmental features might influence

microclimates?

A) a fallen log

B) a tree

C) a stone

D) a discarded soft-drink can

E) all of the above

49) The benthic zone in an aquatic biome

A) is where one would most expect to find a thermocline.

B) is always devoid of light.

C) supports communities of highly motile animals.

D) often supports communities of organisms that feed largely on

detritus.

E) has wider seasonal fluctuations in temperature than other aquatic

zones.

50) A population is correctly defined as having which of the following

characteristics? I. inhabiting the same general area II. individuals belonging to the same species III. possessing a constant and uniform density and dispersion

A) I only

B) III only

C) II and III only

D) I, II, and III

E) I and II only

51) Which of the following statements is consistent with the principle of

competitive exclusion?

A) Bird species generally do not compete for nesting sites.

B) The density of one competing species will have a positive impact

on the population growth of the other competing species.

C) Even a slight reproductive advantage will eventually lead to the

elimination of the less well adapted of two competing species.

D) Evolution tends to increase competition between related species.

E) Two species with the same fundamental niche will exclude other

competing species.

52) Resource partitioning would be most likely to occur between

A) sympatric populations of a predator and its prey.

B) sympatric populations of a flowering plant and its specialized

insect pollinator.

C) sympatric populations of species with similar ecological niches.

D) allopatric populations of species with similar ecological niches.

E) allopatric populations of the same animal species.

53) Which of the following is an example of Müllerian mimicry?

A) a chameleon that changes its color to look like a dead leaf

B) two species of rattlesnakes that both rattle their tails

C) two species of moths with wing spots that look like owl's eyes

D) two species of unpalatable butterfly that have the same color

pattern

E) a day-flying hawkmoth that looks like a wasp

54) Monarch butterflies are protected from birds and other predators but

the cardiac glycosides they incorporate into their tissues are from eating

milkweed when they were in their caterpillar stage of development. The

wings of a different species of butterfly, the Viceroy, look nearly

identical to the Monarch so predators that have learned not to eat the

bad-tasting Monarch avoid Viceroys as well. This example best

describes

A) Batesian mimicry.

B) cryptic coloration.

C) aposmatic coloration.

D) mutualism.

E) Müllerian mimicry.

55) Which of the following terms encompasses all of the others?

A) secondary consumers

B) primary consumers

C) herbivores

D) carnivores

E) heterotrophs

56) What is the most important role of photosynthetic organisms in an

ecosystem?

A) dissipating heat

B) converting energy poor inorganic compounds into energy rich

organic compounds

C) absorbing solar radiation

D) producing organic detritus for decomposers

E) recycling energy from other tropic levels

57) How is it that the open ocean produces the highest net primary

productivity of Earth's ecosystems, yet net primary productivity per

square meter is relatively low?

A) Oceans have the greatest total area.

B) Oceans contain greater concentrations of nutrients compared to

other ecosystems.

C) Oceanic producers are generally much smaller than its consumers.

D) Oceans possess greater species diversity.

E) Oceans receive a greater amount of solar energy per unit area.

58) The high levels of pesticides found in birds of prey is an example of

A) the green world hypothesis.

B) predation.

C) eutrophication.

D) chemical cycling through an ecosystem.

E) biological magnification.

59) You have a friend who is wary of environmentalists' claims that global

warming could lead to major biological change on Earth. Which of the

following statements can you truthfully make in response to your

friend's suspicions?

A) Global warming could have significant effects on United States

agriculture.

B) Sea levels will likely rise, displacing as much as 50% of the world's

human population.

C) Through measurements and observations, we know that carbon

dioxide levels and temperature fluctuations were directly

correlated even in prehistoric times.

D) We know that atmospheric carbon dioxide has increased in the last

150 years.

E) A, B, C, and D are all correct

Use the incomplete diagram below, illustrating some of the steps involved in eutrophication to answer the

following questions.

Figure 55.3

60) What would be a likely entry for box A?

A) fertilizers washed into the lake

B) increased temperature

C) increased sunlight

D) increased ultraviolet radiation

E) elimination of zooplankton

61) What would be a likely entry for box B?

A) fish that cannot acclimate to low oxygen levels

B) warm water holding less oxygen than cold water

C) plants no longer producing oxygen

D) decomposer population carries on cellular respiration and uses up

oxygen

E) carbon dioxide building up from cellular respiration by

decomposers

Section 4—The Cell and Membrane Transport


the question.

62) Which of the following correctly lists the order in which cellular

components will be found in the pellet when homogenized cells are

treated with increasingly rapid spins in a centrifuge?

A) chloroplasts, ribosomes, vacuoles

B) ribosomes, nucleus, mitochondria

C) nucleus, mitochondria, ribosomes

D) vacuoles, ribosomes, nucleus

E) nucleus, ribosomes, chloroplasts

63) A biologist is studying kidney tubules in small mammals. She wants

specifically to examine the juxtaposition of different types of cells in

these structures. The cells in question can be distinguished by external

shape, size, and 3-dimensional characteristics. Which would be the

optimum method for her study?

A) transmission electron microscopy

B) light microscopy using stains specific to kidney function

C) cell fractionation

D) scanning electron microscopy

E) light microscopy using living unstained material

64) Which of the following contains its own DNA and ribosomes?

A) peroxisome

B) vacuole

C) mitochondrion

D) Golgi apparatus

E) lysosome

65) Why isn't the mitochondrion classified as part of the endomembrane

system?

A) It is not involved in protein synthesis.

B) It only has two membrane layers.

C) Its structure is not derived from the ER.

D) It has too many vesicles.

E) It is not attached to the outer nuclear envelope.

66) Microfilaments are well known for their role in which of the following?

A) ameboid movement

B) contracting of muscle cells

C) formation of cleavage furrows

D) A and B only

E) A, B, and C

67) The cell walls of bacteria, fungi, and plant cells and the extracellular

matrix of animal cells are all external to the plasma membrane. Which of

the following is a characteristic of all of these extracellular structures?

A) They are constructed of materials that are largely synthesized in

the cytoplasm and then transported out of the cell.

B) They must block water and small molecules in order to regulate

the exchange of matter and energy with their environment.

C) They must permit information transfer between the cell's

cytoplasm and the nucleus.

D) They must provide a rigid structure that maintains an appropriate

ratio of cell surface area to volume.

E) They are composed of a mixture of lipids and carbohydrates.

68) Of the following molecules of the ECM, which is capable of transmitting

signals between the ECM and the cytoskeleton?

A) integrins

B) fibronectin

C) middle lamella

D) collagen

E) proteoglycans

69) According to the fluid mosaic model of cell membranes, which of the

following is a true statement about membrane phospholipids?

A) They are free to depart from the membrane and dissolve in the

surrounding solution.

B) They frequently flip-flop from one side of the membrane to the

other.

C) They can move laterally along the plane of the membrane.

D) They have hydrophilic tails in the interior of the membrane.

E) They occur in an uninterrupted bilayer, with membrane proteins

restricted to the surface of the membrane.

70) In order for a protein to be an integral membrane protein it would have

to be which of the following?

A) amphipathic

B) completely covered with phospholipids

C) hydrophobic

D) exposed on only one surface of the membrane

E) hydrophilic

71) What kinds of molecules pass through a cell membrane most easily?

A) small and hydrophobic

B) monosaccharides such as glucose

C) ionic

D) large and hydrophobic

E) large polar

72) Water passes quickly through cell membranes because

A) it moves through hydrophobic channels.

B) water movement is tied to ATP hydrolysis.

C) the bilayer is hydrophilic.

D) it moves through aquaporins in the membrane.

E) it is a small, polar, charged molecule.

73) A patient has had a serious accident and lost a lot of blood. In an

attempt to replenish body fluids, distilled water, equal to the volume of

blood lost, is transferred directly into one of his veins. What will be the

most probable result of this transfusion?

A) The patient's red blood cells will swell because the blood fluid is

hypotonic compared to the cells.

B) The patient's red blood cells will shrivel up because the blood fluid

is hypertonic compared to the cells.

C) The patient's red blood cells will shrivel up because the blood fluid

is hypotonic compared to the cells.

D) The patient's red blood cells will burst because the blood fluid is

hypertonic compared to the cells.

E) It will have no unfavorable effect as long as the water is free of

viruses and bacteria.

74) What are the membrane structures that function in active transport?

A) carbohydrates

B) peripheral proteins

C) cholesterol

D) integral proteins

E) cytoskeleton filaments

75) The sodium-potassium pump in animal cells requires cytoplasmic ATP

to pump ions across the plasma membrane. When the proteins of the

pump are first synthesized in the rough ER, what side of the ER

membrane will the ATP binding site be on?

49) ______

A) It will be on the side facing the interior of the ER.

B) It could be facing in either direction because the orientation of

proteins is scrambled in the Golgi apparatus.

C) It doesn't matter, because the pump is not active in the ER.

D) It will be on the cytoplasmic side of the ER.

Section 5—Cell Communication and Cell Division


the question.

76) From the perspective of the cell receiving the message, the three stages

of cell signaling are

A) signal reception, signal transduction, and cellular response.

B) signal reception, cellular response, and cell division.

C) the alpha, beta, and gamma stages.

D) signal reception, nucleus disintegration, and new cell generation.

E) the paracrine, local, and synaptic stages.

77) Synaptic signaling between adjacent neurons is like hormone signaling

in which of the following ways?

A) It requires binding of a signaling molecule to a receptor.

B) It sends its signal molecules through the blood.

C) It persists over a long period.

D) It sends its signal molecules quite a distance.

E) It requires calcium ions.

78) A small molecule that specifically binds to another molecule, usually a

larger one

A) seldom is involved in hormonal signaling.

B) usually terminates a signal reception.

C) is called a ligand.

D) is called a signal transducer.

E) is called a polymer.

79) Up to 60% of all medicines used today exert their effects by influencing

what structures in the cell membrane?

A) ligand-gated ion channel receptors

B) cholesterol

C) G proteins

D) growth factors

E) tyrosine-kinases receptors

80) Testosterone functions inside a cell by

A) becoming a second messenger that inhibits adenylyl cyclase.

B) acting as a signal receptor that activates ion-channel proteins.

C) coordinating a phosphorylation cascade that increases glycogen

metabolism.

D) binding with a receptor protein that enters the nucleus and

activates specific genes.

E) acting as a steroid signal receptor that activates ion-channel

proteins.

81) The general name for an enzyme that transfers phosphate groups from

ATP to a protein is

A) phosphatase.

B) protein kinase.

C) ATPase.

D) phosphorylase.

E) protease.

82) Which of the substances below is a protein that can hold several other

relay proteins as it binds to an activated membrane receptor?

A) ligand

B) protein kinase

C) third messenger

D) active transcription factor

E) scaffolding protein

83) The termination phase of cell signaling requires which of the following?

A) converting ATP to camp

B) reversing the binding of signal molecule to the receptor

C) apoptosis

D) activation of a different set of relay molecules

E) removal of the receptor

84) What is a chromatid?

A) a replicate chromosome

B) a chromosome found outside the nucleus

C) a special region that holds two centromeres together

D) another name for the chromosomes found in genetics

E) a chromosome in G1 of the cell cycle

85) How do the daughter cells at the end of mitosis and cytokinesis

compare with their parent cell when it was in G1 of the cell cycle?

A) The daughter cells have the same number of chromosomes and

twice the amount of DNA.

B) The daughter cells have half the number of chromosomes and half

the amount of DNA.

C) The daughter cells have the same number of chromosomes and the

same amount of DNA.

D) The daughter cells have half the amount of cytoplasm and half the

amount of DNA.

E) The daughter cells have the same number of chromosomes and

half the amount of DNA.

86) If a cell has 8 chromosomes at metaphase of mitosis, how many

chromosomes will it have during anaphase?

A) 2 B) 8 C) 16 D) 1 E) 4

87) Taxol is an anticancer drug extracted from the Pacific yew tree. In

animal cells, taxol disrupts microtubule formation by binding to

microtubules and accelerating their assembly from the protein

precursor, tubulin. Surprisingly, this stops mitosis. Specifically, taxol

must affect

A) anaphase.

B) the fibers of the mitotic spindle.

C) formation of the centrioles.

D) chromatid assembly.

E) the S phase of the cell cycle.

88) Which of the following best describes how chromosomes move toward

the poles of the spindle during mitosis?

A) Motor proteins of the kinetochores move the chromosomes along

the spindle microtubules.

B) Non-kinetochore spindle fibers serve to push chromosomes in the

direction of the poles.

C) The chromosomes are "reeled in" by the contraction of spindle

microtubules.

D) both A and B

E) A, B, and C

89) If mammalian cells receive a go-ahead signal at the G1 checkpoint, they

will

A) show a drop in MPF concentration.

B) move directly into telophase.

C) complete the cycle and divide.

D) exit the cycle and switch to a nondividing state.

E) complete cytokinesis and form new cell walls.

90) Which of the following is a protein maintained at constant levels

throughout the cell cycle that requires cyclin to become catalytically

active?

A) Cdk

B) PDGF

C) protein kinase

D) MPF

E) cyclin

91) The cyclin component of MPF is destroyed toward the end of this phase:

A) M B) G2 C) G1 D) S E) G0

92) Density-dependent inhibition is explained by which of the following?

A) As cells become more numerous, the level of waste products

increases, eventually slowing down metabolism.

B) As cells become more numerous, the cell surface proteins of one

cell contact the adjoining cells and they stop dividing.

C) As cells become more numerous, they begin to squeeze against

each other, restricting their size and ability to produce control

factors.

D) As cells become more numerous, more and more of them enter the

S phase of the cell cycle.

E) As cells become more numerous, the protein kinases they produce

begin to compete with each other, such that the proteins produced

by one cell essentially cancel those produced by its neighbor.

93) Cells from an advanced malignant tumor most often have very

abnormal chromosomes, and often an abnormal total number of

chromosomes. Why might this occur?

A) Cancer cells are no longer anchorage dependent.

B) Transformation introduces new chromosomes into cells.

C) Chromosomally abnormal cells can still go through cell cycle

checkpoints.

D) Chromosomally abnormal cells still have normal metabolism.

E) Cancer cells are no longer density dependent.

94) Besides the ability of some cancer cells to overproliferate, what else

could logically result in a tumor?

A) metastasis

B) changes in the order of cell cycle stages

C) inability of chromosomes to meet at the metaphase plate

D) lack of appropriate cell death

E) inability to form spindles

Section 6—Respiration


the question.

95) What is the term for metabolic pathways that release stored energy by

breaking down complex molecules?

A) catabolic pathways

B) anabolic pathways

C) thermodynamic pathways

D) fermentation pathways

E) bioenergetic pathways

96) Why does the oxidation of organic compounds by molecular oxygen to

produce CO2 and water release free energy?

A) Electrons are being moved from atoms that have a lower affinity

for electrons (such as C) to atoms with a higher affinity for

electrons (such as O).

B) The electrons have a higher potential energy when associated with

water and CO2 than they do in organic compounds.

C) The covalent bonds in organic molecules are higher energy bonds

than those in water and carbon dioxide.

D) The covalent bond in O2 is unstable and easily broken by electrons

from organic molecules.

E) The oxidation of organic compounds can be used to make ATP.

97) Which of the following statements describes NAD+?

A) NAD+ can donate electrons for use in oxidative phosphorylation.

B) NAD+ is reduced to NADH during both glycolysis and the citric

acid cycle.

C) In the absence of NAD+, glycolysis can still function.

D) NAD+ has more chemical energy than NADH.

E) NAD+ is oxidized by the action of hydrogenases.

98) The ATP made during glycolysis is generated by

A) electron transport.

B) photophosphorylation.

C) substrate-level phosphorylation.

D) chemiosmosis.

E) oxidation of NADH to NAD+.

Refer to Figure 9.1 to answer the following questions.

Figure 9.1 illustrates some of the steps (reactions) of glycolysis in their proper sequence. Each

step is lettered. Use these letters to answer the questions.

Figure 9.1

99) In which step is an inorganic phosphate added to the reactant?

100) Which step involves an endergonic reaction?

101) Which step consists of a phosphorylation reaction in which ATP

is the phosphate source?

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

Figure 9.2

102) Starting with one molecule of isocitrate and ending with fumarate, what

is the maximum number of ATP molecules that could be made through

substrate-level phosphorylation?

A) 2 B) 11 C) 24 D) 12 E) 1

103) During aerobic respiration, electrons travel downhill in which

sequence?

A) food → NADH → electron transport chain → oxygen

B) food → glycolysis → citric acid cycle → NADH → ATP

C) food → citric acid cycle → ATP → NAD+ D) glucose → pyruvate → ATP → oxygen

E) glucose → ATP → electron transport chain → NADH

104) In chemiosmotic phosphorylation, what is the most direct source of

energy that is used to convert ADP + Pi to ATP?

A) energy released as electrons flow through the electron transport

system

B) energy released from ATP synthase pumping hydrogen ions from

the mitochondrial matrix

C) No external source of energy is required because the reaction is

exergonic.

D) energy released from substrate-level phosphorylation

E) energy released from movement of protons through ATP synthase

105) Approximately what percentage of the energy of glucose (C6H12O6) is

transferred to storage in ATP as a result of the complete oxidation of

glucose to CO2 and water in cellular respiration?

A) 2% B) 40% C) 25% D) 4% E) 10%

106) In alcohol fermentation, NAD+ is regenerated from NADH during

which of the following?

31) ______

A) phosphorylation of ADP to form ATP

B) reduction of pyruvate to form lactate

C) oxidation of pyruvate to acetyl CoA

D) oxidation of NAD+ in the citric acid cycle

E) reduction of acetaldehyde to ethanol (ethyl alcohol)

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