Chapter 3 - Cellular Energy Flashcards

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1
Q

catabolic processes

A

processes break down large macromolecules into smaller pieces and usually release energy in the form of ATP

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2
Q

anabolic processes

A

extract ebergy from ATP and use it to build larger, more complex macromolecules, where the energy is stores

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3
Q

definition of energy

A

the ability to do work(creating change in a biological system)

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4
Q

chemical energy is a type of ____ enery

A

potential

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5
Q

catabolic reactions ____ free energy, so they are an example of _____ reactions

A

release; exergonic

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6
Q

true or false: catabolic reactions are not spontaneous

A

false - they are spontaneous because they do not require energy input to proceed

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7
Q

anabolic reactions _____ free energy, so they are an example of _____ reactions

A

absorb; endergonic

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8
Q

true or false: anabolic reactions are spontaneous

A

false; non-spontaneous because they require energy input to proceed to the final state

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9
Q

why are ATP molecules unstable?

A

the three phosphate groups are all negatively charged and repel each other

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10
Q

how are bonds between phosphate groups broken in ATP?

A

hydrolysis

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11
Q

describe ATP hydrolysis reactions

A

spontaneous and exergonic

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12
Q

mitochondria has _ membranes

A

two - outer and inner membranes

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13
Q

the mitochondria ___ membrane contains many indentations called ___ that increase surface area

A

inner; cristae

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14
Q

region between outer and inner membranes of the mitochondria is called the ____ ____ and is ____

A

intermembrane space; acidic

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15
Q

the area deep to the inner membrane is called:

A

mitochondrial matrix

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16
Q

example of cells that contain many mitochondria

A

myocytes (human muscle cells)

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17
Q

example of cells that contain no mitochondria

A

red blood cells (lacks most organelles)

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18
Q

the matrix contains its own:

A

circular DNA and ribosomes

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19
Q

endosymbiotic theory

A

states that aerobic bacteria were internalized as mitochondria while the photosynthetic bacteria became chloroplasts

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20
Q

evidence for endosymbiotic theory

A

size similarities and the fact that mitochondria and chloroplasts contain their own circular DNA and ribosomes.

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21
Q

intermembrane space has low or high pH?

A

low pH (acidic)

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22
Q

glycolysis

A

converts glucose to 2 pyruvate

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23
Q

true or false: glycolysis is an anaerobic process

A

true - does not require oxygen

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24
Q

where does glycolysis occur

A

cytosol

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25
Q

two main phases of glycolysis

A
  1. energy investment stage (steps 1-5)

2. energy payoff stage (steps 6-10)

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26
Q

first step of glycolysis

A

glucose gets phosphorylated via one ATP hydrolysis to make glucose-6-phosphate. traps glucose inside the cell

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27
Q

first step of glycolysis enzyme name

A

hexokinase

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28
Q

true or false: 1st step of glycolysis is reversible

A

false - irreversible

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29
Q

2nd step of glycolysis

A

isomerase modifies G6P into F6P (fructose-6-phosphate)

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30
Q

3rd step of glycolysis

A

F6P gets phosphorylated to become fructose-1,6-bisphosphate. irreversible

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31
Q

3rd step of glycolysis enzyme name

A

phosphofructokinase (PFK)

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32
Q

which steps of glycolysis are irreversible

A

1, 3, 10

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33
Q

PFK is an essential ______ enzyme

A

regulatory - Levels of various molecules influence the speed with which phosphofructokinase functions, leading to regulation of the rate of glycolysis as a whole.

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34
Q

Fructose-1,6-bisphosphate is:

A

unstable, so it breaks down into 2 3-carbon sugars

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35
Q

Fructose-1,6-bisphosphate breaks down into:

A

dihydroxyacetone-phosphate (DHAP) and glyceraldehyde-3-phosphate (G3P)

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36
Q

DHAP and G3P exist in:

A

equilibrium

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37
Q

In order to favor the conversion of DHAP into G3P, and not the opposite, the cell must keep G3P levels:

A

low (Le Chatelier’s principle)

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38
Q

DHAP is converted to G3P via:

A

triose phosphate isomerase

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39
Q

Products of glycolysis are:

A
  1. 4 ATP
  2. 2 pyruvate
  3. 2 NADH
40
Q

Net products of glycolysis:

A
  1. 2 ATP (since 2 ATP were used in energy investment phase)
  2. 2 pyruvate
  3. 2 NADH
41
Q

pyruvate molecules have to travel from the ____ to ____

A

cytosol; mitochondrial matrix

42
Q

what happens to pyruvate once it enters mitochondrial matrix?

A
  1. decarboxylated and releases CO2
  2. undergoes oxidation and becomes a 2-carbon acetyl group
  3. this acetyl group binds to Coenzyme A
43
Q

the three pyruvate manipulations are carried out by:

A

pyruvate dehydrogenase

44
Q

pyruvate manipulations produce:

A
  1. 2 CO2
  2. 2 NADH
  3. 2 acetyl-CoA

(for each glucose that enters cellular respiration)

45
Q

pyruvate oxidation step ____ and ____

A

indirectly depends on oxygen; reduces NAD+ to NADH

46
Q

Krebs cycle occurs in:

A

mitochondrial matrix in eukaryotes; cytosol for prokaryotes

47
Q

1st step of Krebs cycle:

A

acetyl-CoA joins oxaloacetate to form citrate (6 carbons)

48
Q

Once citrate is formed:

A

goes through rearrangements. loses 2 carbons via CO2. 2 NAD+ get reduced to NADH

49
Q

After citrate loses 2 carbons:

A

4C molecule progresses, GTP is produced. 4C molecule passes electrons to FAD, FAD is reduced to FADH2

50
Q

After FADH2 is made:

A

the 4C molecule transforms back into oxaloacetate, NAD+ is reduced

51
Q

Krebs cycle products for each glucose:

A
  1. 4 CO2
  2. 6 NADH
  3. 2 FADH2
  4. 2 GTP
52
Q

Krebs cycle occurs _ types per glucose

A

2

53
Q

Krebs cycle ____ depends on oxygen

A

indirectly

54
Q

last step in cellular respiration

A

oxidative phosphorylation (ETC and chemiosmosis)

synthesizes ATP and water

55
Q

___ is the final electron acceptor for aerobic ETCs

A

oxygen. produces water

56
Q

where is the ETC?

A

eukaryotes - inner membrane of mitochondria

prokaryotes - along cell membrane

57
Q

ETC operate through

A

redox reactions

58
Q

enzyme that synthesizes ATP

A

ATP synthase

59
Q

ATP spins via

A

proton motive force

60
Q

full aerobic respiration is ____

A

exergonic (-686 kcal/mol glucose)

61
Q

eukaryotic cells can generate ___ ATP/glucose if they are entirely efficient

A

36-38

62
Q

single NADH can contribute to synthesis of _ ATP

A

3

63
Q

single FADH2 can contribute to synthesis of _ ATP

A

2

64
Q

prokaryotes make __ ATP if entirely efficient

A

38

65
Q

Lactic acid fermentation

A

regenerates NAD⁺ from NADH by reducing pyruvate into lactic acid.

NADH transfers its electrons to pyruvate, regenerating NAD⁺

66
Q

once oxygen has become available again, humans can use ____ ___ to convert lactate back into glucose

A

cori cycle

67
Q

Cori cycle:

A

transports lactate from the myocyte through the bloodstream to liver cells (hepatocytes). Once at a hepatocyte, the lactate can oxidize back into pyruvate. Pyruvate can form glucose through gluconeogenesis.

68
Q

gluconeogenesis from pyruvate in the Cori cycle requires:

A

6 ATP

69
Q

which organ can release glucose into the bloodstream

A

liver - since it contains an enzyme that “undoes” the hexokinase reaction of glycolysis

70
Q

1st step of gluconeogenesis

A

formation of oxaloacetate by carboxylation of pyruvate

71
Q

1st step of gluconeogenesis enzyme

A

pyruvate carboxylase (activated by high levels of Acetyl-CoA)

72
Q

alcohol fermentation

A
  1. pyruvate is decarboxylated to make acetaldehyde

2. NADH reduces this to ethanol, reforming NAD+ to contine glycolysis

73
Q

obligate aerobes

A

organisms that can only metabolize their fuel sources via aerobic respiration, cannot do fermentation

74
Q

obligate anaerobes

A

only metabolize via anaerobic respiration or fermentation; oxygen is toxic

75
Q

facultative anaerobes

A

can utilize aerobic respiration, anaerobic respiration, or fermentation; they will undergo aerobic respiration if they are able to (if oxygen is present).

76
Q

microaerophiles

A

cannot live without oxygen. Therefore they cannot undergo anaerobic respiration or fermentation. However, high concentrations of oxygen are harmful to them.

77
Q

aerotolerant organisms

A

cannot use oxygen; therefore, they only utilize anaerobic respiration or fermentation. However, the presence of oxygen does not poison them.

78
Q

the ___ stores 2/3 of all the body’s glycogen

A

liver

79
Q

___ contain 1/3 of glycogen

A

muscles

80
Q

true or false: humans need to digest fats before absorbing them

A

true

81
Q

___ convert triglycerides into FFA and alcohols

A

lipases

82
Q

how do humans absorb digested fats?

A

through enterocytes of small intestine

83
Q

once in the enterocyte, what happens to FFA and monoglycerides?

A

they will reform into triglycerides, which then pair up with proteins, phospholipids, and cholesterol and form chylomicrons

84
Q

chylomicrons leave enterocytes and enter:

A

lacteals - small lymphatic vessels that take fats to the rest of the body

85
Q

fatty acids can also travel in their free state via

A

binding to albumin

86
Q

Which enzymes are involved in the stages of glycolysis that require ATP investment?

A

hexokinase; phosphofructokinase (steps 1 and 3)

87
Q

Amino acid byproducts can be incorporated into cellular respiration as which molecule?
A. Pyruvate
B. Acetyl-CoA
C. Krebs Cycle Intermediates

A

all of the above

88
Q

Which molecule can undergo direct conversion to glycogen or glucose?

A

glycerol

89
Q
Which of the following can undergo alcohol fermentation?
A. Human muscle cells
B. Yeast
C. Human liver cells
D. Erythrocytes
A

Yeast

90
Q

Which of the following best describes aerobic respiration?

A

Exergonic and spontaneous

91
Q

What molecule is toxic to vertebrates?

A

NH3

92
Q

During fermentation, what is the net ATP yield for every glucose?

A

2

93
Q

At which point of lactic acid fermentation is NAD+ regenerated?

A

when pyruvate is converted to lactate

94
Q

Which molecule is released from glycogen as a result of glycogenolysis?

A

G6P

95
Q

What do lipases convert triglycerides into during lipolysis?

A

free fatty acids and alcohol

96
Q

What is the net GTP yield from the Krebs cycle processing one molecule of glucose?

A

2

97
Q

Which of the following receives electrons from FADH2?

A

Complex II