Chapter 6 Flashcards

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1
Q

Kinetic energy

A

Energy in motion

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2
Q

Potential energy

A

Stored energy

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3
Q

First Law of Thermodynamics

A

Energy cannot be created or destroyed. Energy can only change from one form to another (e.g., potential to kinetic)

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4
Q

Second Law of Thermodynamics

A

Energy cannot be transformed from one form to another with 100% efficiency

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5
Q

Entropy

A

measure of randomness or disorder of a system

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6
Q

Free energy

A

energy available to do work

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7
Q

Endergonic

A

products have more free energy than reactants.

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8
Q

In an endergonic reaction, ∆G is ________.

A

Positive

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9
Q

Exergonic

A

products have less free energy than reactants

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10
Q

In an exergonic reaction, ∆G is ______.

A

Negative

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11
Q

Activation energy

A

energy that must be processed by a molecule in order for it to undergo a chemical reaction

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12
Q

Catalysis

A
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13
Q

ATP is composed of three components:

A
  1. Ribose (5-carbon sugar)
  2. Adenine (composed of two carbon-nitrogen rings)
  3. Three phosphates
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14
Q

Synthesis of ATP from ADP + Pi is _______, which results in a _______ delta-G.

A

Endergonic; positive

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15
Q

Hydrolysis of ATP to ADP + Pi is ________, which results in a _______ delta-G.

A

Exergonic; negative

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16
Q

Substrate

A

molecule on which an enzyme acts

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17
Q

Active site

A

region of an enzyme surface to which a substrate binds

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18
Q

Enzyme-substrate complex

A

complex formed when an enzyme binds with its substrate

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19
Q

Multienzyme complex

A

assembly of several enzymes catalyzing different steps in a sequence of reactions

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20
Q

What is the optimum temperature of enzymes?

A

35-40°C

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21
Q

What is the optimum pH of enzymes?

A

pH 6-8

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22
Q

Inhibitor

A

substance that binds to an enzyme and decreases its activity

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23
Q

Competitive inhibitor

A

Competes with substrate for the same active site

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24
Q

Noncompetitive inhibitor

A

Binds to enzyme in a location other than the active site, changing the enzyme’s shape so it cannot bind the substrate

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25
Q

Allosteric site

A

part of an enzyme away from its active site

26
Q

Allosteric activator

A

substance that binds to allosteric site to keep an enzyme in its active configuration

27
Q

An allosteric activator _______ enzyme activity.

A

Increases

28
Q

Metabolism

A

total of all chemical reactions carried out by an organism

29
Q

Anabolism

A

chemical reaction that expends energy to build up molecules

30
Q

Catabolism

A

chemical reaction that harvests energy by breaking down molecules

31
Q

During a _______ reaction, complex molecules are broken down into simpler compounds.

A

Catabolic

32
Q

Biochemical pathways

A

product of one reaction becomes the substrate of the next reaction

33
Q

During _______ ________, end-product becomes allosteric inhibitor for the first enzyme in the biochemical pathway.

A

Feedback inhibition

34
Q

Energy flows into ecosystems from the ______.

A

Sun

35
Q

The most common way of measuring energy is as _____.

A

Heat

36
Q

Redox reactions transfer ______ energy.

A

Potential

37
Q

The reduced form of a molecule has ______ potential energy than the oxidized form.

A

Higher

38
Q

When energy is converted to another form, some of it is lost as ______.

A

Heat

39
Q

T or F: Order is more likely than disorder.

A

F: disorder is more likely than order

40
Q

Order is ____ stable, and disorder is _____ stable.

A

Less; more

41
Q

What are two ways the rate of reactions can be increased?

A
  1. Increasing energy of reacting molecules (e.g., heating up reactants)
  2. Lowering activation energy (e.g., catalysts)
42
Q

T or F: Catalysts make endergonic reactions faster AND makes them spontaneous.

A

F: Catalysts make endergonic reactions faster BUT NOT spontaneous

43
Q

How does carbonic anhydrase relate to homeostasis in the cell?

A

If blood becomes too acidic, certain reactions cannot happen. Carbonic anhydrase helps maintain level of pH of RBCs

44
Q

Where do enzymes occur in a cell?

A

Cytoplasm and cell membranes/organelle membranes (e.g., mitochondria, nucleus)

45
Q

What are 3 advantages of multienzyme complexes?

A
  1. Keeps next substrate in association with correct enzyme
  2. Limits unwanted side reactions
  3. Controlled as a unit
46
Q

What affects rate of enzyme catalyzed reactions?

A
  1. Temperature
  2. pH
  3. Inhibitors and activators
47
Q

The efficiency of biochemical pathways is coordinated/regulated by the cell. What is meant by efficiency?

A
  • not making a product that is not needed
  • not making energy when there is enough energy
  • not wasting energy/chemical resources
48
Q

An enzyme _____ activation energy.

A

Lowers

49
Q

Increase in temperature of an uncatalyzed reactions _______ its rate.

A

Increases

50
Q

What happens to an enzyme below the optimum temperature?

A

Enzyme’s shape is not flexible enough to permit induced fit (how well substrate fits inside active site)

51
Q

What happens to an enzyme above the optimum temperature?

A

Forces are too weak to maintain enzyme’s shape; enzyme can denature

52
Q

In Gibbs free energy, H =

A

Enthalpy, or the total energy in a molecule’s chemical bonds

53
Q

In Gibbs free energy, TS =

A

Amount of disorder in the system

54
Q

Gibbs free energy is symbolized by ______.

A

G

55
Q

In an endergonic reaction, energy…

A

Must be supplied

56
Q

In an endergonic reaction, energy…

A

Must be supplied

57
Q

In an exergonic reaction, excess energy is

A

Released

58
Q

In an exergonic reaction, excess energy is

A

Released

59
Q

How does energy enter an ecosystem?

A

From the Sun

60
Q

How do biological systems ‘locally’ work to decrease entropy?

A

By expending energy (ATP) constantly

61
Q

How does ATP store energy?

A

By breaking bonds between P-groups (exergonic)