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BIOL 1105 > 7: Energetics of Living Systems > Flashcards

7: Energetics of Living Systems Flashcards

Module 2, Lesson 1 (88 cards)

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1
Q

The ultimate source of energy used in biological systems is usually…

A

The Sun

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2
Q

Photosynthetic organisms use ____ to store chemical energy.

A

Chemical bonds in sugars

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3
Q

____ is the branch of chemistry concerned with energy changes.

A

Thermodynamics

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4
Q

Energy is defined as…

A

The capacity to do work

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5
Q

____ energy is the energy of motion.

A

Kinetic

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6
Q

____ energy is energy that is stored.

A

Potential

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7
Q

List examples of types of energy.

(nine total)

A
  1. Kinetic
  2. Potential
  3. Chemical
  4. Mechanical
  5. Heat
  6. Sound
  7. Electric Current
  8. Light
  9. Radioactivity
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8
Q

____ is a measurement of energy.

A

Heat

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9
Q

A calorie is defined as the…

A

Heat required to raise the temperature of 1 gram of water by 1 degree Celsius.

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10
Q

Cells convert energy into different forms via…

A

Redox reactions

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11
Q

____ occurs when an atom or molecule loses electron(s).

A

Oxidation

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12
Q

____ occurs when an atom or molecule gains electron(s).

A

Reduction

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13
Q

An atom or molecule that loses electrons is said to have been…

A

Oxidized

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14
Q

An atom or molecule that gains electrons is said to have been…

A

Reduced

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15
Q

True or false:

A particle that has been reduced has greater energy than a particle that has been oxidized.

A

True

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16
Q

____ occur when an oxidation and reduction reaction take place together.

A

Oxidation-reduction reactions
(Redox reactions)

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17
Q

A particle that is oxidized transitions to a ____ energy state.

A

Lower

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18
Q

A particle that is reduced transitions to a ____ energy state.

A

Higher

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19
Q

The first law of thermodynamics states that…

A

Energy cannot be created or destroyed; it can only change from one form to another.

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20
Q

During conversion, some energy is lost as…

A

Heat

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21
Q

True or false:

The total amount of energy in the universe is constant.

A

True

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22
Q

The second law of thermodynamics states that…

A

The entropy (disorder) of the universe is constantly increasing.

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23
Q

True or false:

Energy spontaneously converts from a more stable/less ordered form to a less stable/more ordered form.

A

False

Disorder occurs spontaneously, but an energy input is needed to increase order.

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24
Q

The energy available to do work is called…

A

Gibbs free energy
(G)

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25
G = H - TS, where...
G = free energy H = enthalpy T = absolute temperature (K) S = entropy
26
____ is the energy contained in chemical bonds.
Enthalpy
27
A change in free energy is denoted as...
ΔG
28
We can use ΔG to predict whether...
A reaction will occur spontaneously
29
A reaction in which ΔG is ____ will not occur spontaneously.
Positive
30
The products in a reaction where ΔG is positive will have ____ free energy than the reactants.
More
31
A reaction that does not occur spontaneously is termed...
Endergonic
32
A reaction in which ΔG is ____ will likely occur spontaneously.
Negative
33
The products in a reaction where ΔG is negative will have ____ free energy than the reactants.
Less
34
Reactions that occur spontaneously are termed...
Exergonic
35
# True or false: A spontaneous chemical reaction may still require energy in order to begin.
True
36
The energy needed to start a chemical reaction is called the...
Activation energy
37
The ____ of exergonic reactions depends on their activation energy.
Rate
38
Reactions with a larger activation energy will have a ____ reaction rate.
Slower
39
List two ways to increase the rate of a reaction.
1. Increase the energy of the molecules through heating 2. Use a catalyst to lower the activiation energy
40
Substances that lower the activation energy of a reaction are called...
Catalysts
41
# True or false: A catalyst can be used to make an endergonic reaction spontaneous.
False
42
# True or false: Catalysts do not change the proportion of reactants that are converted into products.
True
43
A catalyzed reaction will have a lower ____ than an uncatalyzed reaction.
Activation energy
44
# True or false: The initial and final G values of a reaction are not affected by the presence of a catalyst.
True
45
____ act as biological catalysts.
Enzymes
46
Like all catalysts, enzymes are neither ____ nor ____ in a reaction.
Changed or consumed
47
Most enzymes are ____, but some are ____ molecules.
Proteins; RNA
48
The enzymes in a cell specify its ____ and ____ properties.
Structural and functional
49
List locations in cells where enzymes may be present. | (five)
1. Cytoplasm 2. Cytosol 3. Lumens 4. Plasma membrane 5. Organelle membranes
50
____ are globular proteins with a pocket or cleft for substrate binding.
Enzymes
51
An enzyme's ____ is the location where a specific substrate binds in order for the enzyme to catalyze a reaction.
Active site
52
Enzymes lower a reaction's activation energy by...
Applying stress and distorting the chemical bonds
53
The process by which an enzyme changes shape to maximize contact with a substrate is called...
Induced fit
54
List three factors that influence enzyme function.
1. Concentration of substrate 2. Concentration of enzyme 3. Any chemical or physical condition that affects enzyme structure
55
Conditions that can affect the structure of enzymes include... | (three)
1. Temperature 2. pH 3. Regulatory molecules
56
Regulatory molecules that can decrease enzyme activity by binding to it and changing its shape are called...
Inhibitors
57
Cells can determine which enzymes are active and which are inactive using...
Regulatory molecules
58
____ enzymes can switch between active and inactive states.
Allosteric
59
____ inhibitors bind to an enzyme's active site in place of a substrate.
Competitive
60
____ inhibitors bind to an enzyme at a location other than its active site and change its shape to prevent binding.
Noncompetitive
61
The location where noncompetitive inhibitors bind to an enzyme is called the...
Allosteric site
62
Regulatory molecules that bind to enzymes in order to activate them are called...
Enzyme activators
63
The total of all chemical reactions performed by an organism is its...
Metabolism
64
The ____ metabolism expends energy to synthesize molecules.
Anabolic (Anabolism)
65
The ____ metabolism harvests energy using the breakdown of molecules.
Catabolic (Catabolism)
66
In ____, chemical reactions occur in sequence, where the product of one reaction becomes the substrate for the next.
Biochemical pathways
67
Cells can use ____ to control biochemical pathways.
Feedback inhibition
68
During feedback inhibition...
The pathway's end-product binds to the allosteric site on the enzyme that catalyzes the first reaction in the pathway.
69
It is desirable for cells to control biochemical pathways so that...
Raw materials and energy aren't wasted and excess end-product is not produced
70
The main source of chemical potential energy is...
ATP
71
ATP contains two ____ bonds, which are unstable and are easily broken during hydrolysis.
High-energy
72
Breaking high-energy bonds in ATP provides energy for...
Endergonic reactions
73
Most ATP reactions hydrolyze...
Only the outermost phosphate
74
When only the outermost phosphate is hydrolyzed, ____ and ____ are produced.
ADP and one inorganic phosphate | (ADP stands for "adenosine diphosphate")
75
Some ATP reactions hydrolyze...
Two phosphate groups
76
When two phosphate groups are hydrolyzed, ____ and ____ are produced.
AMP and 2 inorganic phosphates | (AMP stands for "adenosine monophosphate")
77
# True or false: ATP is good at storing energy for long periods of time.
False ATP is best for short-term energy storage. For long-term storage, cells usually use fats or carbohydrates.
78
# True or false: ATP has a very high turnover rate in cells - it is constantly being made and used.
True
79
How much ATP do cells usually store?
Only a few seconds' worth
80
Cells often use ATP to power coupled reactions, where...
An exergonic and endergonic reaction combine so the overall ΔG is negative
81
In a coupled reaction, the exergonic component is often...
ATP hydrolysis
82
ATP synthesis depends on energy from ____ reactions.
Exergonic
83
The products of ATP hydrolysis are then used as...
Reactants in ATP synthesis
84
____ helps cells control protein activity.
ATP
85
Cells control protein activity using a reversible process that involves...
Phosphorylation and dephosphorylation
86
The enzyme ____ "turns on" a protein by hydrolyzing ATP, then attaching the released phosphate group to a protein.
Kinase
87
The enzyme ____ "turns off" a protein by removing the phosphate group from its amino acid sidechain.
Phosphotase
88
# True or false: Phosphorylation always causes the target protein to be activated.
False Some target proteins are actually inactivated as a result of phosphorylation.

BIOL 1105 (26 decks)

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