Finals Study Guide 2 Flashcards


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1

A primary objective of cell fractionation is to
A) view the structure of cell membranes.
B) determine the size of various organelles.
C) separate lipid-soluble from water-soluble molecules.
D) sort cells based on their size and weight.
E) separate the major organelles so that their particular functions can be determined.

E) separate the major organelles so that their particular functions can be determined.

2

All of the following are part of a prokaryotic cell except
A) a cell wall.
B) ribosomes.
C) DNA.
D) a plasma membrane.
E) an endoplasmic reticulum.

E) an endoplasmic reticulum.

3

Large numbers of ribosomes are present in cells that specialize in producing which of the following
molecules?
A) cellulose
B) proteins
C) nucleic acids
D) lipids
E) glycogen

B) proteins

4

Which type of organelle or structure is primarily involved in the synthesis of oils, phospholipids,
and steroids?
A) smooth endoplasmic reticulum
B) lysosome
C) contractile vacuole
D) ribosome
E) mitochondrion

A) smooth endoplasmic reticulum

5

In a plant cell, DNA may be found
A) in the nucleus, mitochondria, chloroplasts, and peroxisomes.
B) only in the nucleus.
C) only in the nucleus and mitochondria.
D) only in the nucleus and chloroplasts.
E) in the nucleus, mitochondria, and chloroplasts.

E) in the nucleus, mitochondria, and chloroplasts.

6

Plasmodesmata in plant cells are most similar in function to which of the following structures in
animal cells?
A) extracellular matrix
B) desmosomes
C) gap junctions
D) peroxisomes
E) tight junctions

C) gap junctions

7

A biologist ground up some plant leaf cells and then centrifuged the mixture to fractionate the
organelles. Organelles in one of the heavier fractions could produce ATP in the light, whereas
organelles in the lighter fraction could produce ATP in the dark. The heavier and lighter fractions
are most likely to contain, respectively,
A) mitochondria and peroxisomes.
B) mitochondria and chloroplasts.
C) chloroplasts and peroxisomes.
D) chloroplasts and mitochondria.
E) peroxisomes and chloroplasts.

D) chloroplasts and mitochondria.

8

Singer and Nicolson's fluid mosaic model of the membrane proposed that
A) membranes are a phospholipid bilayer.
B) membranes are a phospholipid bilayer between two layers of hydrophilic proteins.
C) membranes consist of protein molecules embedded in a fluid bilayer of phospholipids.
D) membranes consist of a mosaic of polysaccharides and proteins.
E) membranes are a single layer of phospholipids and proteins.

C) membranes consist of protein molecules embedded in a fluid bilayer of phospholipids.

9

Which of the following is one of the ways that the membranes of winter wheat are able to remain
fluid when it is extremely cold?
A) by decreasing the number of hydrophobic proteins in the membrane
B) by using active transport
C) by increasing the percentage of cholesterol molecules in the membrane
D) by cotransport of glucose and hydrogen
E) by increasing the percentage of unsaturated phospholipids in the membrane

E) by increasing the percentage of unsaturated phospholipids in the membrane

10

What kinds of molecules pass through a cell membrane most easily?
A) ionic
B) monosaccharides such as glucose
C) small and hydrophobic
D) large polar
E) large and hydrophobic

C) small and hydrophobic

11

Which of the following statements is correct about diffusion?
A) It requires integral proteins in the cell membrane.
B) It is a passive process in which molecules move from a region of higher concentration to a
region of lower concentration.
C) It is very rapid over long distances.
D) It is an active process in which molecules move from a region of lower concentration to one of
higher concentration.
E) It requires an expenditure of energy by the cell.

B) It is a passive process in which molecules move from a region of higher concentration to a
region of lower concentration.

12

Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45
M NaCl. What will happen if red blood cells are transferred to seawater?
A) The blood cells will expend ATP for active transport of NaCl into the cytoplasm.
B) The blood cells will take up water, swell, and eventually burst.
C) NaCl will passively diffuse into the red blood cells.
D) Water will leave the cells, causing them to shrivel and collapse.
E) NaCl will be exported from the red blood cells by facilitated diffusion.

D) Water will leave the cells, causing them to shrivel and collapse.

13

Proton pumps are used in various ways by members of every domain of organisms: Bacteria,
Archaea, and Eukarya. What does this most probably mean?
A) Proton gradients across a membrane were used by cells that were the common ancestor of all
three domains of life.
B) Proton pumps must have evolved before any living organisms were present on Earth.
C) Proton pumps are necessary to all cell membranes.
D) The high concentration of protons in the ancient atmosphere must have necessitated a pump
mechanism.
E) Cells of each domain evolved proton pumps independently when oceans became more acidic.

A) Proton gradients across a membrane were used by cells that were the common ancestor of all
three domains of life.

14

White blood cells engulf bacteria through what process?
A) phagocytosis
B) exocytosis
C) pinocytosis
D) osmosis
E) receptor-mediated exocytosis

A) phagocytosis

15

Which of the following processes includes all others?
A) passive transport
B) diffusion of a solute across a membrane
C) facilitated diffusion
D) osmosis
E) transport of an ion down its electrochemical gradient

A) passive transport

16

Which of the following is a statement of the first law of thermodynamics?
A) The entropy of the universe is decreasing.
B) Energy cannot be transferred or transformed.
C) Energy cannot be created or destroyed.
D) The entropy of the universe is constant.
E) Kinetic energy is stored energy that results from the specific arrangement of matter.

C) Energy cannot be created or destroyed.

17

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an
organism. How does this relate to the second law of thermodynamics?
A) Living organisms do not follow the laws of thermodynamics.
B) Living organisms are able to transform energy into entropy.
C) Living organisms do not obey the second law of thermodynamics, which states that entropy
must increase with time.
D) Life obeys the second law of thermodynamics because the decrease in entropy as the
organism grows is exactly balanced by an increase in the entropy of the universe.
E) As a consequence of growing, organisms cause a greater increase in entropy in their
environment than the decrease in entropy associated with their growth.

E) As a consequence of growing, organisms cause a greater increase in entropy in their
environment than the decrease in entropy associated with their growth.

18

Which of the following is an example of potential rather than kinetic energy?
A) water rushing over Niagara Falls
B) a molecule of glucose
C) the flight of an insect foraging for food
D) light flashes emitted by a firefly
E) the muscle contractions of a person mowing grass

B) a molecule of glucose

19

19) A system at chemical equilibrium
A) consumes energy at a steady rate.
B) has zero kinetic energy.
C) releases energy at a steady rate.
D) can do no work.
E) consumes or releases energy, depending on whether it is exergonic or endergonic.

D) can do no work.

20

When glucose monomers are joined together by glycosidic linkages to form a cellulose polymer, the
changes in free energy, total energy, and entropy are as follows:
A) +

B) ++-

21

Which of the following statements is true about enzyme-catalyzed reactions?
A) The reaction is faster than the same reaction in the absence of the enzyme.
B) Enzyme-catalyzed reactions require energy to activate the enzyme.
C) Enzyme-catalyzed reactions release more free energy than noncatalyzed reactions.
D) The free energy change of the reaction is opposite from the reaction that occurs in the absence
of the enzyme.
E) The reaction always goes in the direction toward chemical equilibrium.

A) The reaction is faster than the same reaction in the absence of the enzyme.

22

A solution of starch at room temperature does not readily decompose to form a solution of simple
sugars because
A) the activation energy barrier for this reaction cannot be surmounted.
B) starch hydrolysis is nonspontaneous.
C) the hydrolysis of starch to sugar is endergonic.
D) the starch solution has less free energy than the sugar solution.
E) starch cannot be hydrolyzed in the presence of so much water.

A) the activation energy barrier for this reaction cannot be surmounted.

23

When you have a severe fever, what grave consequence may occur if the fever is not controlled?
A) change in the tertiary structure of your enzymes
B) binding of your enzymes to inappropriate substrates
C) removal of amine groups from your proteins
D) destruction of your enzymes' primary structure
E) removal of the amino acids in active sites of your enzymes

A) change in the tertiary structure of your enzymes

24

How does a noncompetitive inhibitor decrease the rate of an enzyme reaction?
A) by acting as a coenzyme for the reaction
B) by changing the free energy change of the reaction
C) by binding at the active site of the enzyme
D) by decreasing the activation energy of the reaction
E) by changing the shape of the enzyme's active site

E) by changing the shape of the enzyme's active site

25

What is the term for metabolic pathways that release stored energy by breaking down complex
molecules?
A) catabolic pathways
B) thermodynamic pathways
C) bioenergetic pathways
D) anabolic pathways
E) fermentation pathways

A) catabolic pathways

26

When electrons move closer to a more electronegative atom, what happens?
A) The more electronegative atom is oxidized, and energy is released.
B) The more electronegative atom is oxidized, and energy is consumed.
C) The more electronegative atom is reduced, and energy is consumed.
D) The more electronegative atom is reduced, and energy is released.
E) The more electronegative atom is reduced, and entropy decreases.

D) The more electronegative atom is reduced, and energy is released.

27

Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water
release free energy?
A) The covalent bond in O2 is unstable and easily broken by electrons from organic molecules.
B) The electrons have a higher potential energy when associated with water and CO2 than they
do in organic compounds.
C) The oxidation of organic compounds can be used to make ATP.
D) The covalent bonds in organic molecules and molecular oxygen have more kinetic energy
than the covalent bonds in water and carbon dioxide.
E) 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).

E) 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).

28

Which of the following statements describes NAD+?
A) NAD+ can donate electrons for use in oxidative phosphorylation.
B) In the absence of NAD+, glycolysis can still function.
C) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.
D) NAD+ is oxidized by the action of hydrogenases.
E) NAD+ has more chemical energy than NADH.

C) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.

29

Where does glycolysis take place in eukaryotic cells?
A) mitochondrial outer membrane
B) mitochondrial matrix
C) mitochondrial inner membrane
D) mitochondrial intermembrane space
E) cytosol

E) cytosol

30

The oxygen consumed during cellular respiration is involved directly in which process or event?
A) the phosphorylation of ADP to form ATP
B) accepting electrons at the end of the electron transport chain
C) glycolysis
D) the citric acid cycle
E) the oxidation of pyruvate to acetyl CoA

B) accepting electrons at the end of the electron transport chain

31

Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
A) glycolysis
B) electron transport
C) chemiosmosis
D) oxidative phosphorylation
E) the citric acid cycle

A) glycolysis

32

In addition to ATP, what are the end products of glycolysis?
A) CO2 and H2O
B) NADH and pyruvate
C) CO2 and pyruvate
D) CO2 and NADH
E) H2O, FADH2, and citrate

B) NADH and pyruvate

33

Why is glycolysis described as having an investment phase and a payoff phase?
A) It attaches and detaches phosphate groups.
B) It uses glucose and generates pyruvate.
C) It uses stored ATP and then forms a net increase in ATP.
D) It both splits molecules and assembles molecules.
E) It shifts molecules from cytosol to mitochondrion.

C) It uses stored ATP and then forms a net increase in ATP.

34

During aerobic respiration, electrons travel downhill in which sequence? 34)
A) food

A) food>NADH>electron transport chain>oxygen

35

In cellular respiration, the energy for most ATP synthesis is supplied by
A) a proton gradient across a membrane.
B) converting oxygen to ATP.
C) high energy phosphate bonds in organic molecules.
D) transferring electrons from organic molecules to pyruvate.
E) generating carbon dioxide and oxygen in the electron transport chain.

A) a proton gradient across a membrane.

36

Where is ATP synthase located in the mitochondrion?
A) outer membrane
B) cytosol
C) mitochondrial matrix
D) electron transport chain
E) inner membrane

E) inner membrane

37

Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to
carbon dioxide (CO2) and water?
A) oxidation of pyruvate to acetyl CoA
B) glycolysis
C) oxidative phosphorylation (chemiosmosis)
D) fermentation
E) citric acid cycle

C) oxidative phosphorylation (chemiosmosis)

38

Approximately how many molecules of ATP are produced from the complete oxidation of two
molecules of glucose (C6H12O6) in aerobic cellular respiration?
A) 30—32 B) 15 C) 2 D) 60—64 E) 4

D) 60—64

39

What is proton-motive force?
A) the force required to remove an electron from hydrogen
B) the force that moves hydrogen into the mitochondrion
C) the force exerted on a proton by a transmembrane proton concentration gradient
D) the force that moves hydrogen to NAD+
E) the force that moves hydrogen into the intermembrane space

C) the force exerted on a proton by a transmembrane proton concentration gradient

40

Which of the following normally occurs regardless of whether or not oxygen (O2) is present?
A) glycolysis
B) oxidative phosphorylation (chemiosmosis)
C) fermentation
D) oxidation of pyruvate to acetyl CoA
E) citric acid cycle

A) glycolysis

41

The ATP made during fermentation is generated by which of the following?
A) substrate-level phosphorylation
B) oxidative phosphorylation
C) the electron transport chain
D) aerobic respiration
E) chemiosmosis

A) substrate-level phosphorylation

42

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
A) It requires the presence of membrane-enclosed cell organelles found only in eukaryotic cells.
B) It produces much less ATP than does oxidative phosphorylation.
C) It relies on chemiosmosis, which is a metabolic mechanism present only in the first cells'
prokaryotic cells.
D) It is found in prokaryotic cells but not in eukaryotic cells.
E) It does not involve organelles or specialized structures, does not require oxygen, and is
present in most organisms.

E) It does not involve organelles or specialized structures, does not require oxygen, and is
present in most organisms.

43

You have a friend who lost 7 kg (about 15 pounds) of fat on a regimen of strict diet and exercise.
How did the fat leave her body?
A) It was broken down to amino acids and eliminated from the body.
B) It was released as CO2 and H2O.
C) It was converted to heat and then released.
D) It was converted to urine and eliminated from the body.
E) It was converted to ATP, which weighs much less than fat.

B) It was released as CO2 and H2O.

44

Phosphofructokinase is an important control enzyme in the regulation of cellular respiration.
Which of the following statements correctly describes phosphofructokinase activity?
A) It is inhibited by AMP.
B) It is an allosteric enzyme.
C) It is activated by citrate, an intermediate of the citric acid cycle.
D) It catalyzes the conversion of fructose 1,6-bisphosphate to fructose 6-phosphate, an early step
of glycolysis.
E) It is activated by ATP.

B) It is an allosteric enzyme.

45

Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of
pyruvate. When and where will this occur?
A) in cells that are storing glucose only
B) in photosynthesizing cells in the light and in other tissues in the dark
C) in nonphotosynthesizing cells only
D) in all cells all the time
E) in photosynthetic cells in the light, while photosynthesis occurs concurrently

D) in all cells all the time

46
card image

Which of the following most accurately describes what is happening along the respiration electron
transport chain in Figure 9.3?
A) Each electron carrier alternates between being reduced and being oxidized.
B) ATP is generated at each step.
C) Energy of the electrons increases at each step.
D) Molecules in the chain give up some of their potential energy.
E) Chemiosmosis is coupled with electron transfer.

A) Each electron carrier alternates between being reduced and being oxidized.

47

Which of the following are products of the light reactions of photosynthesis that are utilized in the
Calvin cycle?
A) H2O and O2
B) electrons and H+
C) CO2 and glucose
D) ATP and NADPH
E) ADP, i, and NADP+

D) ATP and NADPH

48

Where does the Calvin cycle take place?
A) thylakoid membrane
B) outer membrane of the chloroplast
C) cytoplasm surrounding the chloroplast
D) stroma of the chloroplast
E) interior of the thylakoid (thylakoid space)

D) stroma of the chloroplast

49

When oxygen is released as a result of photosynthesis, it is a direct by-product of
A) reducing NADP+.
B) the electron transfer system of photosystem II.
C) splitting water molecules.
D) chemiosmosis.
E) the electron transfer system of photosystem I.

C) splitting water molecules.

50

A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow.
What wavelengths of visible light are being absorbed by this pigment?
A) red and yellow
B) green and yellow
C) blue and violet
D) green, blue, and yellow
E) blue, green, and red

C) blue and violet

51

Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer
separated from the stroma. This damage will have the most direct effect on which of the following
processes?
A) the synthesis of ATP
B) the absorption of light energy by chlorophyll
C) the reduction of NADP+
D) the flow of electrons from photosystem II to photosystem I
E) the splitting of water

A) the synthesis of ATP

52

Which of the following statements best describes the relationship between photosynthesis and
respiration?
A) ATP molecules are produced in photosynthesis and used up in respiration.
B) Respiration runs the biochemical pathways of photosynthesis in reverse.
C) Respiration is anabolic and photosynthesis is catabolic.
D) Photosynthesis stores energy in complex organic molecules, whereas respiration releases it.
E) Photosynthesis occurs only in plants and respiration occurs only in animals.

D) Photosynthesis stores energy in complex organic molecules, whereas respiration releases it.

53

In photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during
A) respiration only.
B) both photosynthesis and respiration.
C) photorespiration only.
D) photosynthesis only.
E) neither photosynthesis nor respiration.

B) both photosynthesis and respiration.

54

What is the primary function of the Calvin cycle?
A) synthesize simple sugars from carbon dioxide
B) use ATP to release carbon dioxide
C) transport RuBP out of the chloroplast
D) use NADPH to release carbon dioxide
E) split water and release oxygen

A) synthesize simple sugars from carbon dioxide

55

Which of the following statements best represents the relationships between the light reactions and
the Calvin cycle?
A) The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle
supplies the light reactions with sugars to produce ATP.
B) The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP,
i, and NADP+ to the light reactions.
C) The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin
cycle provides the light reactions with water to split.
D) There is no relationship between the light reactions and the Calvin cycle.
E) The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle,
and the cycle provides water and electrons to the light reactions.

B) The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP,
i, and NADP+ to the light reactions.

56

In the process of carbon fixation, RuBP attaches a CO2 to produce a six-carbon molecule, which is
then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction
produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin
cycle?
A) inactivation of RuBP carboxylase enzyme
B) addition of a pair of electrons from NADPH
C) regeneration of NADP+
D) regeneration of RuBP
E) regeneration of ATP from ADP

D) regeneration of RuBP

57

Photorespiration occurs when rubisco reacts RuBP with
A) glyceraldehyde 3-phosphate.
B) CO2.
C) NADPH.
D) 3-phosphoglycerate.
E) O2.

E) O2.

58

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because
they
A) use photosystem I and photosystem II at night.
B) fix CO2 into organic acids during the night.
C) use the enzyme phosphofructokinase, which outcompetes rubisco for CO2.
D) fix CO2 into pyruvate in the mesophyll cells.
E) fix CO2 into sugars in the bundle-sheath cells.

B) fix CO2 into organic acids during the night.

59

Plants photosynthesize only in the light. Plants respire
A) both in light and dark.
B) in the dark only.
C) only when excessive light energy induces photorespiration.
D) in the light only.
E) never–they get their ATP from photophosphorylation.

A) both in light and dark.

60

How is photosynthesis similar in C4 plants and CAM plants?
A) In both cases, thylakoids are not involved in photosynthesis.
B) In both cases, only photosystem I is used.
C) In both cases, rubisco is not used to fix carbon initially.
D) Both types of plants make most of their sugar in the dark.
E) Both types of plants make sugar without the Calvin cycle.

C) In both cases, rubisco is not used to fix carbon initially.