Biology: A Guide to the Natural World, 5e (Krogh)
Chapter 6 Life’s Mainspring: An Introduction to Energy
1) Plants provide animals with which of the following?
A) food
B) oxygen
C) carbon dioxide
D) food and oxygen
E) food and carbon dioxide
2) Which law of thermodynamics explains the fact that we must eat to gain the energy to perform
the functions of life, such as breathing?
A) second law
B) fourth law
C) fifth law
D) first law
E) third law
3) Living things are highly ordered. So why does life not violate the second law of
thermodynamics?
A) Life can only violate the first law of thermodynamics.
B) Life only needs to follow the first law of thermodynamics.
C) Life takes in energy to maintain order and, in doing so, decreases order elsewhere.
D) Life gives off energy to maintain order and, in doing so, decreases order elsewhere.
4) Which of the following has the most entropy?
A) steam
B) snow
C) an ice cube
D) hot water
E) liquid water
5) When we metabolize our food, we produce heat that helps to keep us warm. Which of the
following best describes why?
A) Chewing is exothermic; therefore, energy is released in the form of heat when we eat food.
B) When we break down food, all energy in the food is directly released in the form of heat.
C) Producing ATP from ADP is exothermic; therefore, energy is released in the form of heat.
D) When we break down our food, the reactions are not 100 percent efficient; therefore, energy
is lost as heat.
6) Entropy is the measure of ________ in a system.
A) energy
B) disorder
C) work
D) order
E) heat
7) When you digest the starch in plants into glucose, some energy is lost as heat. This increases
the ________ of the universe.
A) energy
B) order
C) entropy
D) potential
E) equilibrium
8) Glucose can be broken down to provide energy for the beating of cilia. Therefore, the glucose
must contain:
A) potential energy.
B) kinetic energy.
C) heat energy.
D) entropy.
9) Kinetic energy is ________ and potential energy is ________.
A) stored energy; energy that is being used
B) stored energy; energy that can’t be used
C) energy that can’t be used; stored energy
D) energy that is being used; stored energy
10) You work hard to pedal your bicycle up a steep hill. You rest when you get to the top, then
you let your bicycle roll quickly down the other side of the hill. You converted ________ energy
into ________ energy, then you converted it back into ________ energy.
A) potential; kinetic; potential
B) kinetic; potential; kinetic
C) heat; kinetic; heat
D) heat; potential; heat
11) Which of the following accurately describes energy?
A) something that can cause movement
B) something that produces heat
C) something that has the capacity to do work
D) something that must be eaten
E) something that provides sunlight
12) The first law of thermodynamics states that:
A) energy is required to bring molecules into a cell against a concentration gradient.
B) in energy-yielding reactions, matter goes from a more-ordered to a less-ordered state.
C) energy can be neither created nor destroyed.
D) all living organisms must eat to derive energy.
13) The second law of thermodynamics states that:
A) energy is required to bring molecules into a cell against a concentration gradient.
B) energy can be neither created nor destroyed.
C) all living organisms must eat to derive energy.
D) in energy-yielding reactions, matter goes from a more-ordered to a less-ordered state.
14) What percentage of the energy stored in glucose do humans recover by cellular respiration?
A) 100 percent
B) 48 percent
C) 52 percent
D) 37 percent
E) 15 percent
15) During photosynthesis, plants use light energy to synthesize glucose from carbon dioxide.
However, plants do not use up energy during photosynthesis; they merely convert it from light
energy to chemical energy. This is an illustration of:
A) spontaneous reaction.
B) chemical equilibrium.
C) the second law of thermodynamics.
D) the first law of thermodynamics.
E) increasing entropy.
16) Energy present in a system that is not usable to do work relates to the system’s:
A) thermodynamics.
B) equilibrium.
C) work.
D) entropy.
E) temperature.
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17) Which of the following is true of energy?
A) It can be stored in chemical bonds.
B) It can be released by forming chemical bonds.
C) It can be transferred from one form to another with 100 percent efficiency.
D) It can be created from nothing.
18) Which of the following is endergonic?
A) cells breaking down glucose into CO2
B) the burning of wood
C) the digestion of proteins in the stomach
D) breaking bonds in starch to produce glucose
E) the synthesis of glucose from carbon dioxide and water
19) Which of the following is exergonic?
A) bringing glucose molecules together to form glycogen
B) plants producing glucose from CO2
C) bringing amino acids together to form proteins
D) cells breaking down glucose into CO2
20) In the reaction glucose + oxygen → carbon dioxide + heat, the:
A) products have more potential energy than the reactants.
B) products have less potential energy than the reactants.
C) products have the same amount of potential energy as the reactants.
D) entropy has decreased.
21) Coupled reactions are:
A) reactions in which endergonic reactions obtain the energy to go forward from exergonic
reactions.
B) reactions in which exergonic reactions obtain the energy to go forward from endergonic
reactions.
C) any reactions that are accelerated by an enzyme.
D) reactions that lower the activation energy of another reaction.
22) The energy released during ________ reactions can be used to drive ________ reactions, and
this is called ________ reactions.
A) endergonic; exergonic; coupled
B) exergonic; endergonic; coupled
C) endergonic; exergonic; mutually dependent
D) exergonic; endergonic; mutually dependent
23) What is the energy currency of cells?
A) ATP
B) glucose
C) enzymes
D) ADP
E) vitamins
24) In the ATP/ADP cycle:
A) food provides the energy needed to link phosphate to ADP to make ATP.
B) food provides the energy needed to break down ATP into ADP.
C) converting ADP into ATP is an energy-yielding reaction, whereas converting ATP into ADP
is an energy-requiring reaction.
D) after powering a reaction, ADP becomes ATP.
25) The structure of ATP includes each of the following except:
A) the nitrogenous base adenosine.
B) the sugar ribose.
C) the nitrogenous base adenine.
D) phosphate groups.
26) In the following reaction, which of the following is an example of a substrate?
Lactase
Lactose → Glucose + Galactose
A) galactose
B) glucose
C) lactose
D) lactase
27) The substance that is worked on by an enzyme is called:
A) product.
B) coenzyme.
C) inhibitor.
D) substrate.
28) You have a friend who tells you she is lactose intolerant. She asks you to explain what this
means. You say to her:
A) “You cannot digest milk because you cannot absorb it in your intestines.”
B) “You are allergic to milk.”
C) “You cannot digest milk because you do not have the enzyme to break down the sugar in the
milk.”
D) “You cannot digest the milk because you do not have the enzyme to break down the protein
in the milk.”
E) “You cannot digest the milk because you do not have the enzyme to break down the lipid in
the milk.”
29) The diversity of chemical reactions occurring in a cell depends mostly on certain molecules
present in the cells, which are called:
A) enzymes.
B) proteins.
C) cofactors.
D) coenzymes.
E) ribozymes.
30) In a ________, multiple enzymes are working together in a multistep process.
A) feedback loop
B) coupled reaction
C) allosteric pathway
D) metabolic pathway
31) Metabolism is the sum of all the:
A) ATP a cell contains.
B) energy a cell uses.
C) chemical reactions that a cell carries out.
D) vitamins a cell contains.
E) enzymes a cell contains.
32) Enzymes work to speed up a chemical reaction by:
A) supplying the energy needed for the reaction.
B) increasing the activation energy of the reaction.
C) lowering the activation energy of the reaction.
D) attaching coenzymes to the substrate.
E) heating up the substrate.
33) Some enzymes contain molecules in the active site that help facilitate chemical
transformations. These molecules are called:
A) coenzymes.
B) products.
C) substrates.
D) co-substrates.
34) Gasoline will not burn in your car’s engine unless it is ignited with a spark from a sparkplug.
In this situation, the spark is providing:
A) activation energy.
B) hydrolytic energy.
C) coenzyme energy.
D) enzymatic energy.
E) entropy.
35) What makes an enzyme a catalyst?
A) its ability to change shape to fit the substrate
B) it speeds up a chemical reaction but can only be used once
C) it speeds up a chemical reaction but becomes changed by the reaction
D) it speeds up a chemical reaction but is not changed by the reaction
E) its amino acids
36) Most enzymes are:
A) proteins.
B) nucleic acids.
C) lipids.
D) vitamins.
E) carbohydrates.
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37) Which of the following statements concerning enzymes is false?
A) They function as catalysts.
B) The active site of an enzyme has a shape that is specific for its given substrate.
C) They increase the activation energy required for chemical reactions to proceed.
D) Many enzymes utilize coenzymes, such as vitamins.
38) Which would be an example of a catalyst in action?
A) a glycoprotein binding to a cell
B) a protein converting glucose and fructose into sucrose without being changed itself
C) glucose and galactose binding to form lactose
D) a phosphate group attached to a protein changing its shape
39) Coenzymes:
A) serve as catalysts.
B) make proteins.
C) help enzymes to function.
D) break down sugars.
40) Which of the following statements concerning enzymes is false?
A) They accelerate the rate of chemical reactions.
B) Many activities in living organisms require multiple enzymes.
C) One enzyme will work on many different substrate molecules to produce many different
products.
D) They can carry out hundreds of chemical transformations per second.
41) Where do substrates bind to enzymes?
A) in the active site
B) anywhere
C) in the substrate groove
D) in the effector site
42) Which of the following is true of vitamins?
A) They serve as a major energy source for cells.
B) They are the main component of enzymes.
C) They can serve as enzymes.
D) They can serve as coenzymes.
43) The function of chymotrypsin is to:
A) break down proteins into amino acids.
B) synthesize glycogen.
C) synthesize proteins.
D) break down glycogen into glucose.
44) Which of the following describes a transition state molecule?
A) the distorted shape the product takes while being released from the enzyme
B) the distorted shape the substrate takes when being converted by an enzyme into product
C) the distorted shape the enzyme takes when converting substrate into product
D) the distorted shape a coenzyme takes while it is bound to an enzyme
45) Methyl alcohol, also known as wood alcohol, is a common solvent and paint remover. It is
poisonous if accidentally swallowed. The enzyme alcohol dehydrogenase in the liver converts
methyl alcohol into formaldehyde, which then gets converted into a toxic product. Grain alcohol,
ethyl alcohol, is also acted upon by alcohol dehydrogenase. One antidote for methyl alcohol
poisoning is to make a person drink a lot of ethyl alcohol. This blocks the active site of the
enzyme so that it can’t bind to and break down the methyl alcohol. In this capacity, the ethyl
alcohol is acting as a/an:
A) allosteric regulator.
B) coenzyme.
C) competitive inhibtor.
D) precursor.