Week 6

Question 1

Which does not represent an energy transformation?

a) the coupling of ATP hydrolysis to the production of a proton gradient across a membrane by a proton pump
b) the release of carbon dioxide as glucose is broken down during cellular respiration
c) the production of sugars from carbon dioxide and water during photosynthesis
d) the production of ATP using phosphate from the breakdown of glucose
e) All of the listed responses represent energy transformations.

Answer 1

b) the release of carbon dioxide as glucose is broken down during cellular respiration

Question 2

Which is an example of the cellular work accomplished with the free energy derived from the hydrolysis of ATP, involved in the production of electrochemical gradients?

a) H+ (proton) movement against a gradient of protons
b) chromosome movement on microtubules
c) the beating of cilia
d) facilitated diffusion
e) the chemical synthesis of ATP

Answer 2

a) H+ (proton) movement against a gradient of protons

Question 3

In general, the hydrolysis of ATP drives cellular work by __________.
Group of answer choices

releasing free energy that can be coupled to other reactions

lowering the free energy of the reaction

acting as a catalyst

changing to ADP and phosphate

releasing heat

Answer 3

a) releasing free energy that can be coupled to other reactions

Question 4

When 1 mole of ATP is hydrolyzed in a test tube without an enzyme, about twice as much heat is given off as when 1 mole of ATP is hydrolyzed in a cell. Which best explains these observations?

a) Cells have the ability to store heat; this cannot happen in a test tube.
b) In cells, ATP is hydrolyzed to ADP and Pi, but in the test tube it is hydrolyzed to carbon dioxide and water.
c) Cells are less efficient at energy metabolism than reactions that are optimized in a test tube.
d) In the cell, the hydrolysis of ATP is coupled to other reactions which are endergonic.
e) The amount of heat released by a reaction has nothing to do with the free energy change of the reaction.

Answer 4

d) In the cell, the hydrolysis of ATP is coupled to other reactions which are endergonic.

Question 5

Which functional group is associated with a release of energy when removed from an ATP molecule via hydrolysis?

a) sulfhydryl

b) phosphate

c) amino

d) hydroxyl

e) carboxyl

Answer 5

b) phosphate

Question 6

A chemical reaction is designated as exergonic rather than endergonic when __________.

a) activation energy is required
b) the potential energy of the products is less than the potential energy of the reactants
c) it absorbs more energy
d) the products are less complex than the reactants
e) activation energy exceeds net energy release

Answer 6

b) the potential energy of the products is less than the potential

Question 7

Which aspect of a reaction is changed by the presence of an enzyme?

a) the sign of delta G
b) the activation energy needed
c) the magnitude of delta G
d) the G value for the products
e) the G value for the reactants

Answer 7

b) the activation energy needed

Question 8

What do the sign (+ or -) and magnitude of the delta G of a reaction tell us about the speed of the reaction?

a) The sign does not matter, but the larger the magnitude of delta G, the faster the reaction.
b) The sign does not matter, but the smaller the magnitude of delta G, the faster the reaction.
c) The more negative the delta G, the faster the reaction is.
d) Neither the sign nor the magnitude of delta G has anything to do with the speed of a reaction.
e) The sign determines whether the reaction is spontaneous, and the magnitude determines the speed.

Answer 8

d) Neither the sign nor the magnitude of delta G has anything to do with the speed of a reaction.

Question 9

How do enzymes lower activation energy?

a) by increasing reactivity of products
b) by locally concentrating the reactants in a position in which they are more likely to react
c) by harnessing heat energy to drive the breakage of bonds between atoms
d) The first two responses above are correct.
e) The second and third choices are correct.

Answer 9

b) by locally concentrating the reactants in a position in which they are more likely to react

Question 10

Which statement about enzymes is true?
a) The more heat that is added to a reaction, the faster the enzymes will function.
b) Enzymes speed up the rate of the reaction without changing the delta G for the reaction.
c) Enzymes react with their substrate (form chemical bonds), forming an enzyme-substrate complex, which irreversibly alters the enzyme.
d) Enzymes increase the rate of a reaction by raising the activation energy for reactions.
e) All of the listed choices are correct

Answer 10

b) Enzymes speed up the rate of the reaction without changing the delta G for the reaction.

Question 11

Consider the growth of a farmer’s crop over a season. Which correctly states a limitation imposed by the first or second law of thermodynamics?

a) The entropy of the universe must decrease to account for the increased entropy associated with plant growth.
b) To obey the first law, the crops must represent an open system.
c) The process of photosynthesis produces energy that the plant uses to grow.
d) Growth of the crops must occur spontaneously.
e) All of the listed choices are correct.

Answer 11

b) To obey the first law, the crops must represent an open system.

Question 12

Which statement about enzyme function is correct?
a) Enzymes can change the equilibrium point of reactions, but they cannot speed up reactions because they cannot change the net energy output.
b) Enzymes can greatly speed up reactions, but they cannot change the net energy output because they cannot change the activation energy.
c) Enzymes can lower the activation energy of reactions, but they cannot change the equilibrium point because they cannot change the net energy output.
d) Enzymes can greatly speed up reactions, but they cannot change the activation energy because they cannot change the net energy output.
e) None of the above

Answer 12

c) Enzymes can lower the activation energy of reactions, but they cannot change the equilibrium point because they cannot change the net energy output.

Question 13

Which statement about the active site of an enzyme is correct?

a) The structure of the active site is not affected by changes in temperature.
b) The active site has a fixed structure (shape).
c) The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.
d) Coenzymes are rarely found in the active site of an enzyme.
e) The active site allows the reaction to occur under the same environmental conditions as the reaction without the enzyme.

Answer 13

c) The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.

Question 14

Which correctly describe(s) the role(s) of heat in biological reactions?

a) Heat from the environment is necessary for substrates to get over the activation energy barrier.
b) The kinetic energy of the substrates is increased as the amount of heat in the system is increased.
c)Increasing the amount of heat in a system will increase the rate of enzyme-catalyzed reactions.
d) The first and second choices are correct.
e) The second and third choices are correct

Answer 14

d) The first and second choices are correct.

Question 15

Above a certain substrate concentration, the rate of an enzyme-catalyzed reaction drops as the enzymes become saturated. Which would lead to a faster conversion of substrate into product under these saturated conditions?

a)an increase in the concentration of enzyme
b)lowering the temperature by a few degrees
c)increasing the substrate concentration
d)None of the responses are correct
e)The second, and third listed responses are correct.

Answer 15

a)an increase in concentration of enzyme

Question 15

Which environment or action would not affect the rate of an enzymatic reaction?

a) pH
b)substrate concentration
c)cooling the enzyme
d) heating the enzyme
e)None of the listed responses are correct

Answer 15

e)None of the listed responses are correct

Question 16

A catalyzed reaction is different from an uncatalyzed reaction because in the catalyzed reaction

a) the reactants have more free energy.
b) the energy barrier has been lowered.
c) the products have less free energy.
d) the catalyst breaks the first law of thermodynamics.
e)the catalyst eliminates all endergonic steps of th

Answer 16

b) the energy barrier has been lowered.

Question 17

The ability to do work or the capacity to cause change is an example of __________.

a) pinocytosis
b) energy
c) phagocytosis
d) All of the choices are examples.
e) None

Answer 17

b) energy

Question 18

Which state the relevance of the first law of thermodynamics to biology?

a) Photosynthetic organisms produce energy in sugars from sunlight.
b) Energy is destroyed as glucose is broken down during cellular respiration.
c) Energy can be freely transformed among different forms as long as the total energy is conserved.
d) Living organisms must increase the entropy of their surroundings.
e) The total energy taken in by an organism must be greater than the total energy stored or released by the organism.

Answer 18

c) Energy can be freely transformed among different forms as long as the total energy is conserved.

Question 19

Which is the most abundant form of energy in a cell?

a) chemical energy
b) heat
c) electrochemical gradients
d) mechanical energy

Answer 19

a) chemical energy

Question 20

If the entropy of a living organism is decreasing, which is most likely to be occurring at the same time?

a )Energy input into the organism must be occurring to drive the decrease in entropy.
b) The entropy of the organism’s environment must also be decreasing.
c) In this situation, the second law of thermodynamics must not apply.
d) The first law of thermodynamics is being violated.
e) Heat is being used by the organism as a source of energy.

Answer 20

a )Energy input into the organism must be occurring to drive the decrease in entropy.

Question 21

Are most chemical reactions at equilibrium in living cells?

a) yes
b) no
c) only the exergonic reactions
d) all reactions except those powered by ATP hydrolysis
e) None of the listed options are correct.

Answer 21

b) no

Question 22

Is it true that the breakdown of food in the gut does not require ATP hydrolysis, but enzymes are required to speed up these spontaneous reactions?

a) true, because food contains abundant energy to be released
b) false, because enzymes change the ∆G to a negative value
c) false, because enzymes are not required, as breakdown is spontaneous and spontaneous reactions always occur very rapidly
d) true, because ADP is used, not ATP
e) None of the answer choices are correct

Answer 22

a) true, because food contains abundant energy to be released

Question 23

If normal human body temperature is 37°C, what temperature would be optimal for many human enzymes?

a) 2°C
b) 7°C
c) 17°C
d) 27°C
e) 37°C

Answer 23

e) 37°C

Question 24

What is a good analogy for the induced fit of a substrate into an enzyme’s active site? a) a pencil in a sharpener b) two hands shaking c) solid tires turning on a road d) teeth biting an apple e) All of the choices are correct

Answer 24

b) two hands shaking

Question 25

Why can the breakdown of ATP power cellular processes? a) It is an endergonic reaction that can be coupled with other reactions. b) As an exergonic reaction, it releases energy to spare. c) It takes up excess free energy that interferes with metabolism. d) It helps warm cells and speed metabolism. e) It generates ADP for the synthesis of RNA

Answer 25

b) As an exergonic reaction, it releases energy to spare.

Question 26

If you observed a chemical reaction proceed spontaneously in a cell, which of the following would be true? a) The reaction was exergonic. b) The reactants had more free energy than the products. c) The products included ATP. d) A and B e) A and c

Answer 26

d) A and B

Question 27

Which has the most free energy per molecule? a) a sugar molecule b) an amino acid molecule c) a starch molecule d) a cholesterol molecule e) a fatty acid molecule

Answer 27

c) a starch molecule

Question 28

An exergonic (spontaneous) reaction is a chemical reaction that __________. a) occurs only when an enzyme or other catalyst is present b) is common in anabolic pathways c) cannot occur outside of a living cell d) leads to a decrease in the entropy of the universe e) releases free energy when proceeding in the forward direction

Answer 28

e) releases free energy when proceeding in the forward direction

Question 29

Which reaction would be endergonic? a) glucose + fructose → sucrose b) C6H12O6 + 6 O2 → 6 CO2 + 6 H2O c) HCl → H+ + Cl- d) ATP → ADP + Pi e) All of the listed responses are correct.

Answer 29

a) glucose + fructose → sucrose

Question 30

Which determines the sign of delta G for a reaction? a) the free energy of the reactants b) the enzyme catalyzing the reaction having a high affinity (strength of binding) for the reactants c) the free energy of the products d) the free energy of the reactants and the free energy of the products e) the enzyme catalyzing the reaction having a low affinity for the products

Answer 30

d) the free energy of the reactants and the free energy of the products

Question 31

Which statement about osmosis is correct? a) The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis. b) If a cell is placed in an isotonic solution, more water will enter the cell than leave the cell. c) Osmotic movement of water into a cell would likely occur if the cell accumulates water from its environment. d) If a solution outside the cell is hypertonic compared to the cytoplasm, water will move into the cell by osmosis. e) Osmosis is the diffusion of water from a region of lower water concentration to a region of higher water concentration.

Answer 31

a) The presence of aquaporins (proteins that form water channels in the membrane) should speed up the process of osmosis.

Question 32

Movement of water out of a cell that has been placed in a hypertonic solution is a) passive transport/diffusion. b) active transport. c) passive transport. diffusion. d) ctive transport/diffusion.

Answer 32

a) passive transport/diffusion.

Question 33

If you were studying a cell undergoing lots of active transport, which nucleotide would you expect to find in greatest abundance? a) ATP b) GTP c) UTP d) TTP

Answer 33

a) ATP

Question 34

If a cell membrane were hydrophilic, with pores larger than most proteins, could it be selectively permeable in a living system? a) No; any substances could pass through. b) Yes; this is a typical cell membrane. c) Yes; it would keep other large cells out. d) No; proteins need to diffuse into cells. e) Yes; proteins are the main thing kept outside a cell by membranes.

Answer 34

a) No; any substances could pass through.

Question 35

What do transport proteins do for cells? a) speed up transport and increase the kinds of molecules entering cells b) speed up transport c) increase the kinds of molecules entering cells d) act as enzymes e) increase the kinds of molecules entering cells and act as enzymes

Answer 35

a) speed up transport and increase the kinds of molecules entering cells

Question 36

All of the following are examples of endocytosis, EXCEPT: a) osmosis b) phagocytosis c) pinocytosis d) receptor-mediated endocytosis

Answer 36

a) osmosis

Question 37

The sodium-potassium pump is the major electrogenic pump of plant cells. True False

Answer 37

False

Question 38

Bulk transport requires energy. Correct Answer True False

Answer 38

True

Question 39

Familial hypercholesterolemia is an inherited genetic disease in which lipoprotein receptors responsible for receptor-mediated endocytosis of cholesterol are defective or missing. True False

Answer 39

TRUE

Question 40

If an enzyme is added to a solution in which its substrate and product are in equilibrium, what will occur? a) The reaction will change from endergonic to exergonic. b) None of the listed choices is correct. c) Nothing; the reaction will stay at equilibrium. d) Additional product will be formed. e) The free energy of the system will change

Answer 40

c) Nothing; the reaction will stay at equilibrium.

Question 41

A mutation in the active site of an enzyme is most likely to affect a) None of the listed scenarios apply here b) the products of a chemical reaction, but not the reactants c) movement of an enzyme within a cell d) complete globular structure of an enzyme e) catalytic activity of an enzyme

Answer 41

e) catalytic activity of an enzyme

Question 42

If you placed an algal cell that had been living in a marine aquarium into a glass of pure water, what would happen? a) Water would bind to receptors. b) None of the listed choices is correct. c) The cell would lose water. d) The cell would turn on cell signaling. e) The cell would take up water

Answer 42

e) The cell would take up water

Question 43

Metabolic pathways in cells are typically far from equilibrium. Which process tends to keep these pathways away from equilibrium? a) the continuous removal of the products of a pathway to be used in other reactions b) an input of free energy from outside the pathway c) an input of heat from the environment d) The first and second listed responses are correct. e) The first, second, and third listed responses are correct.

Answer 43

d) The first and second listed responses are correct.

Question 44

Which of the following is the most comprehensive definition of metabolism in living organisms? a) Metabolism manages the increase of entropy in an organism. b) Metabolism consists of all the energy transformation reactions in an organism. c) Metabolism refers to the sum of all biochemical pathways involved in the synthesis of macromolecules. d) None of the listed choices is correct. e) Metabolism depends on a constant supply of energy from food.

Answer 44

b) Metabolism consists of all the energy transformation reactions in an organism.

Question 44

The cellular process of synthesizing large molecules from smaller ones is defined as a) anabolism. b) catalysis. c) catabolism. d) dehydration. e) metabolism.

Answer 44

a) anabolism.

Question 45

You are observing a newly discovered form of protist, and you see an organelle suddenly decrease in volume. What has happened? a) The cell was avoiding bursting. b) All of the choices are correct. c) The cell used its contractile vacuole. d) The cell was osmoregulating. e) The cell was counteracting osmosis.

Answer 45

b) All of the choices are correct.

Question 46

Which of the following processes includes all the others? a) transport of an ion down its chemical gradient b) diffusion of a solute across a membrane c) passive transport d) osmosis

Answer 46

c) passive transport

Question 47

Which of the following statements is true for all exergonic reactions? a) A net input of energy from the surroundings is required for the reaction to proceed. b) None of the listed choices is correct. c) The reaction goes only in a forward direction: all reactants will be converted to products, but no products will be converted to reactants. d) The products have more total energy than the reactants. e) The reaction proceeds with a net release of free energy.

Answer 47

e) The reaction proceeds with a net release of free energy.

Question 48

Which enables a cell to pick up and concentrate a specific kind of molecule (e.g., cholesterol)? a) osmosis b) facilitated diffusion c) receptor-mediated endocytosis d) channel proteins

Answer 48

c) receptor-mediated endocytosis

Question 49

Which of the descriptions below is an example of an exergonic reaction? a) None of the listed choices is correct. a dehydration reaction between two b) monosaccharides to produce a disaccharide c) synthesis of ATP from ADP and ℗i d) hydrolysis of glycogen to release glucose monomers e) formation of a peptide bond

Answer 49

d) hydrolysis of glycogen to release glucose monomers

Question 50

Which would be least likely to diffuse through a plasma membrane without the help of a transport protein? a) a large polar molecule b) a small nonpolar molecule c) dissolved gases such as oxygen or carbon dioxide d) a large nonpolar molecule e) All of the choices would easily diffuse through the membrane

Answer 50

a) a large polar molecule

Question 51

Cells, such as bacteria, are taken up by other cells, such as immune cells, by which process? a) exocytosis b) phagocytosis c) receptor-mediated endocytosis d) pinocytosis e) facilitated diffusion

Answer 51

b) phagocytosis

Question 52

Which cell structure allows selective permeability between a cell and its external environment? a) endoplasmic reticulum b) chloroplasts c) mitochondria d) lysosomes e) the plasma membrane

Answer 52

e) the plasma membrane

Question 53

An accident victim has lost a lot of blood due to a serious injury. Replacement of the lost body fluids with distilled water would have which of the following results? a) It will have no unfavorable effect as long as the water is free of viruses and bacteria. b) The patient's red blood cells will shrivel up because the blood fluid has become hypertonic compared to the cells. c) The patient's red blood cells will shrivel up because the blood fluid has become hypotonic compared to the cells. d) The patient's red blood cells will swell and lyse because the blood fluid has become hypotonic compared to the cells. e) None of the listed scenarios apply here.

Answer 53

d) The patient's red blood cells will swell and lyse because the blood fluid has become hypotonic compared to the cells.

Question 53

Which statement is false in regard to facilitated diffusion? a) Facilitated diffusion can occur using transport proteins. b) Facilitated diffusion requires the hydrolysis of ATP. c) Facilitated diffusion can occur through protein channels. d) Facilitated diffusion can move ions across membranes.

Answer 53

b) Facilitated diffusion requires the hydrolysis of ATP.

Question 54

Which of the following statements about diffusion is correct? a) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration. b) It is very rapid over long distances. c) It requires an expenditure of energy by the cell. d) It is a passive process in which molecules move from a region of lower concentration to a region of higher concentration. e) It is an active process in which molecules move from a region of lower concentration to one of higher concentration.

Answer 54

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

Question 55

If a sugar needed by a cell was found at higher concentration inside the cell than outside, what would the cell need to do? a) open ion channels b) dissolve its plasma membrane c) lower its membrane potential d) perform phagocytosis e) perform active transport

Answer 55

e) perform active transport

Question 56

Which correctly states a difference between active transport and facilitated diffusion? a) Facilitated diffusion involves transport proteins, and active transport does not. b) Active transport involves transport proteins, and facilitated diffusion does not. c) Facilitated diffusion can move solutes against a concentration gradient, and active transport cannot. d) Active transport can move solutes in either direction across a membrane, but facilitated diffusion can only move in one direction at a time. e) Active transport always requires energy from ATP, and facilitated diffusion does not.

Answer 56

e) Active transport always requires energy from ATP, and facilitated diffusion does not.

Question 57

In most exergonic reactions, before products can be formed, the reactants must first overcome a thermodynamic barrier known as the a) chemical equilibrium of the reaction. b) None of the listed choices is correct. c) activation energy of the reaction. d) entropy of the reaction. e) energy conservation of the reaction

Answer 57

c) activation energy of the reaction.

Question 58

The cellular process of breaking down large molecules into smaller ones is defined as a) metabolism. b) catalysis. c) dehydration. d) anabolism. e) catabolism.

Answer 58

e) catabolism.

Question 59

The active site of an enzyme is the region that a) is blocked by the presence of a coenzyme or a cofactor. b) binds substrates for the enzyme. c) binds noncompetitive inhibitors of the enzyme. d) None of the listed choices is correct. e) binds allosteric regulators of the enzyme

Answer 59

b) binds substrates for the enzyme.

Question 60

What is the best definition of equilibrium? a) Equal amounts of a cell in different parts of an organism. b) Equal concentrations of a substance inside and outside of the cell. c) None of the listed responses are correct d) Slightly lower concentration inside the cell compared to the outside of the cell e) Slightly higher concentration outside the cell compared to the inside of the cell.

Answer 60

b) Equal concentrations of a substance inside and outside of the cell.

Question 61

Which statement about diffusion is true? a) It is a passive process of a substance across a membrane with no energy investment b) It always requires integral proteins of the cell membrane. c) It is very rapid over long distances. d) It occurs when molecules move from a region of lower concentration to a region of higher concentration. e) It requires expenditure of energy by the cell.

Answer 61

a) It is a passive process of a substance across a membrane with no energy investment

Question 62

Why might a severely high fever result in death if it is not brought under control? a) It may result in the consumption of excess ATP. b) It may alter the tertiary and quaternary structures of cellular enzymes. c) It may destroy the primary structure of cellular enzymes. d) None of the listed choices is correct. e) It may increase threat of cellular chemical reactions

Answer 62

b) It may alter the tertiary and quaternary structures of cellular enzymes.

Question 62

The sodium-potassium pump transports both ions against their concentration gradients. True False

Answer 62

True

Question 63

When chemical, transport, or mechanical work is performed by an organism, what happens to the heat that is generated? a) It is used to synthesize ADP. b) It is used to power yet more cellular work. c) None of the listed choices is correct. d) It is released to the environment. e) It is used to store energy in the form of ATP.

Answer 63

d) It is released to the environment.

Question 64

Energy transformations in organisms are always associated with a) a decrease in the free energy of the organism. b) an increase in the free energy of the universe. c) None of the listed choices is correct. d) an increase in the entropy of the universe.

Answer 64

d) an increase in the entropy of the universe.

Question 65

If you place a culture of animal cells into a container filled with molecules of red dye that has a strong negative charge, and the dye ends up inside the cell, what is the most likely explanation? a) active transport b) phagocytosis c) pinocytosis d) None of the answers is correct. e) osmosis

Answer 65

c) pinocytosis

Question 66

In which case would osmosis occur? a) a skin cell in a hypotonic solution b) a beaker of water with salt dissolved and evenly mixed in it c) None of the listed choices is correct. d) cell coated with an impermeable plastic coating e) a red blood cell in an isotonic solution

Answer 66

a) a skin cell in a hypotonic solution

Question 66

ATP is a molecule that acts as an intermediary to store energy for cellular work

Question 67

Which of the following membrane activities requires energy from ATP hydrolysis? a) movement of glucose molecules into a bacterial cell from a medium containing a higher concentration of glucose than inside the cell b) movement of water into a cell through aquaporins c) movement of carbon dioxide out of a paramecium d) facilitated diffusion of chloride ions across the membrane through a chloride channel e) movement of sodium ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Answer 67

e) movement of sodium ions from a lower concentration in a mammalian cell to a higher concentration in the extracellular fluid

Question 68

Green olives can be preserved in brine, a 30% salt solution. How does this method of preservation prevent microorganisms from growing in the olives? a) Bacteria can get energy from the salt. b) A 30% salt solution is hypertonic to the bacteria, so they lose too much water and plasmolyze (burst) c) High salt concentration lowers the pH, thus inhibiting bacterial metabolism. d) Bacterial cells shrivel up in high-salt solutions, causing the cell to burst. e) A 30% salt solution is isotonic to the bacteria, so they enter dormancy.

Answer 68

b) A 30% salt solution is hypertonic to the bacteria, so they lose too much water and plasmolyze (burst)

Question 69

For what would active transport be needed? a) None of the listed choices is correct. b) uptake of a hydrophobic dye that was newly placed in a solution c) release of dye from a crystal placed in solution d) uptake of potassium from a solution rich in sodium by a cell rich in potassium e) release of sodium from a cell that stores it

Answer 69

d) uptake of potassium from a solution rich in sodium by a cell rich in potassium

Question 70

A metabolic pathway begins with a specific molecule and ends with a product. True False

Answer 70

TRUE

Question 70

A living cell has what kind of gradient across its membrane? a) electrical and chemical b ) electrical c) chemical d) light-driven e) physical

Answer 70

a) electrical and chemical

Question 71

Most cells cannot harness heat to perform work because a) heat does not involve a transfer of energy. b) cells do not have much heat; they are relatively cool. c) heat can never be used to do work. d) temperature is usually uniform throughout a cell.

Answer 71

d) temperature is usually uniform throughout a cell.