Chapter 6 - Energy Transfer in the Body Flashcards

1
Q

What is the Energy Currency of the Body?

A
  • ATP
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2
Q

What provides major sources of potential energy?

A
  • Macronutrients
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3
Q

How does ADP form?

A
  • When ATP joins with water
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4
Q

What enzyme catalyzes the reaction of ATP and Water to form ADP?

A
  • Adenosine Triphosphatase (ATPase)
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5
Q

What are the Cells’ two major energy-transforming activities?

A
  • Extract potential energy from food/conserve it within ATP bonds
  • Extract/transfer chemical energy in ATP to power biological work
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6
Q

How much ATP does the body store at resting condition?

A
  • 80-100g ATP
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7
Q

How long can resting stores of ATP in the body provide energy?

A

2-3 seconds of Maximal Exercise

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8
Q

What ways can the mitochondria produce ATP?

A
  • Citric Acid Cycle
  • Respiratory Chain (Aerobic)
  • Pyruvate from glucose
  • Some deaminated amino acids
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9
Q

What ways for ATP production occur in the Cytosol?

A
  • Glycolysis (Anaerobic)
  • Phosphocreatine
  • Glucose/Glycogen
  • Glycerol
  • Some Deamniated Amino Acids
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10
Q

Where does Aerobic ATP production occur?

A
  • Mitochondria
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11
Q

Where does Anaerobic ATP production occur?

A
  • Cytosol
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12
Q

Where does ATP production from phosphocreatine occur?

A
  • Cytosol
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13
Q

What happens with the anaerobic splitting of a phosphate from Phosphocreatine?

A
  • ATP resynthesis
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14
Q

How much Phosphocreatine do cells store compared to ATP?

A
  • 4-6 times
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15
Q

How long can Phosphocreatine provide energy for?

A
  • around 10s
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16
Q

What does Adenylate Kinase Reaction represent?

A
  • single-enzyme mediated reaction for ATP
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17
Q

Where does most energy for phosphorylation derive from?

A
  • Carbohydrates
  • Lipids
  • Protein
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18
Q

What do oxidation reactions do?

A
  • Donate electrons
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19
Q

What do Reduction reactions do?

A
  • Accept Electrons
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20
Q

What constitutes the biochemical mechanism that underlies energy metabolism?

A
  • RedOx Reactions (oxidation - reduction)
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21
Q

What do redox reactions provide from catabolism of stored macronutrients?

A
  • Hydrogen Atoms
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22
Q

What are the energy factories in the mitochondria? What do they do?

A

What
- Carrier Molecules
Do
- Remove electrons from hydrogen (oxidation)
- Pass them to oxygen (reduction)
- Synthesis ATP

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23
Q

Are hydrogen atoms turned loose in intracellular fluids during cellular oxidation?

A
  • NO
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24
Q

What catalyze’s hydrogen’s release from the nutrient substrate?

A
  • substrate-specific dehydrogenase enzymes
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25
Q

What accepts pairs of electrons from hydrogen?

A
  • coenzyme component of the dehydrogenase
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26
Q

What happens when Nicotinamide Adenine Dinucleotide (NAD+) gains hydrogen and two electrons?

A

-Reduces to NADH

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27
Q

What happens to the other Hydrogen when one pairs with NAD+?

A
  • Appears in the cell fluid as H+
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28
Q

How many electrons does Flavin Adenine Dinucleotide accept?

A
  • Two
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29
Q

What are NAD+ and FAD?

A
  • Electron Acceptors
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30
Q

What are Cytochromes?

A
  • A series of Iron-protein electron carriers dispersed on the inner membranes of the mitochondrion
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31
Q

What is a bucket brigade?

A
  • Passing of electrons carried by NADH and FADH2 down the Cytochromes
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32
Q

What represents the final common pathway where electrons extracted from hydrogen pass to oxygen?

A
  • Electron Transport
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33
Q

What drives the respiratory chain? How?

A

Oxygen
- serving as final electron acceptor to combine with hydrogen to form water

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34
Q

What happens for each pair of hydrogen atoms that reach the cytochrome?

A
  • Two Electrons flow down the chain and reduce to one atom of oxygen
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35
Q

What is released during the passage of electrons down the chain?

A
  • Enough energy to re-phosphorylate ADP to ATP`
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36
Q

How does oxidative phosphorylation synthesize ATP?

A
  • Transfer of electrons from NADH and FADH2 to oxygen
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37
Q

How much ATP synthesis occurs in the respiratory chain by oxidative reactions coupled with phosphorylation?

A
  • 90%
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38
Q

How many coupling sites during the electron transport does energy transfer from NADH to ADP to reform ATP?

A
  • three distinct places
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39
Q

Why do only 2 ATP molecules form for each hydrogen pair oxidized from FADH2?

A
  • FADH2 enters respiratory chain at lower energy level
  • Beyond point of first ATP synthesis
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40
Q

What is the result of shuttling hydrogen in the electron transport chain requiring energy?

A

On Average
- NADH produces 2.5 ATP
- FADH2 produces 1.5 ATP

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41
Q

How much energy does 1 mole of ATP formed from ADP + P conserve?

A
  • 7kcal energy
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42
Q

What is the relative efficiency level for harnessing chemical energy via the electron transport oxidative phosphorylation?

A
  • 34%
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43
Q

What is created by electron transport energy-releasing reactions in the mitochondria?

A
  • Proton (H+) gradient across the inner mitochondrial membrane
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44
Q

What provides the electrochemical basis for coupling electron transport to oxidative phosphorylation to form ATP?

A
  • Stored energy in the inner mitochondrial membrane
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45
Q

What three prerequisites exist for continual re-synthesis of ATP during coupled oxidative phosphorylation?

A
  • Tissue availability of NADH and FADH2
  • Presence of oxygen in tissue (oxidizing agent)
  • Sufficient concentration of enzyme and mitochondria to ensure energy transfer reactions proceed at appropriate rate
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46
Q

What are the 6 fuel sources?

A
  • Phosphocreatine
  • Anaerobic Glycolysis
  • Blood Glucose
  • Triacylglycerol and Glycogen Molecules
  • Free Fatty Acids
  • Carbon Skeleton of Amino Acids
47
Q

What controls the phosphorylation of ADP from PCr?

A

Enzyme Control
- Creatine Kinase
- Adenylate Kinase

48
Q

Where are triacylglycerol’s stored?

A
  • Within Muscle Cells
49
Q

Where are the carbon skeletons of amino acids located?

A
  • Intramuscular
  • Liver-derived
50
Q

What is the only macronutrient substrate whose stored energy generates ATP without oxygen?

A
  • Carbohydrates
51
Q

What is required for processing a large quantity of fat for energy?

A
  • minimal carbohydrate breakdown
52
Q

What aerobic breakdown occurs faster, Carbs or Fats?

A
  • Carbs
53
Q

What requires an uninterrupted supply of carbs to function properly?

A
  • The central nervous system
54
Q

If we received 100% of energy from 1 full glucose, how much energy would we get?

A
  • 686 kcal
55
Q

How do we determine the yield of ATP from the breakdown of 1 Glucose?

A

1 Full Glucose 100% - 686kcal
34% Efficiency - 686x0.34 = 233kcal
7.3kcal/mol
233kcal/7.3kcal/mol = 32mol

56
Q

What happens to the rest of the potential energy after the breakdown of glucose?

A
  • Dissipated as heat
57
Q

What are the two forms of carbohydrate breakdown?

A
  • Anaerobic Glycolysis
  • Aerobic Glycolysis
58
Q

How much energy is released from Anaerobic Glycolysis of Glucose?

A
  • 5%
59
Q

What results from the Anaerobic Glycolysis of Glucose?

A
  • pyruvate-to-lactate formation
  • Release of 5% energy
60
Q

What is the result of Aerobic Glycolysis of Glucose?

A
  • Pyruvate-to-Acetyl Coenzyme A- to Citric Acid Cycle and Electron transport chain
  • Release of all available energy from glucose
61
Q

What is the First Step of Anaerobic Glycolysis?

A
  • Glucose to Glucose 6-phosphate
62
Q

What does the conversion of Glucose to Glucose-6-phosphate require?

A
  • 1 ATP
  • Hexokinase Enzyme
63
Q

What does the Enzyme Hexokinase catalyze?

A
  • Glucose to Glucose-6-phosphate
64
Q

What is not required to convert Glycogen to Glucose-6-phosphate?

A
  • ATP
  • Hexokinase Enzyme
65
Q

Where does Glycolysis take place?

A
  • Cytosol
66
Q

What does Glucose break down into following Glycolysis? What does it net?

A
  • 2 Pyruvates
  • Gains 2 ATP
67
Q

What does Glycogen break down into following glycolysis? what does it net?

A
  • 2 Pyruvates
  • Gain 3 ATP
68
Q

What is Glycogenesis?

A
  • Glycogen Synthesis
69
Q

Explain Glycognesis

A

Glycogen Synthesis
- Surplus Glucose forms Glycogen
- Occurs in low cellular activity
- Facilitate by Glycogen Synthase
- Glucose links to large Glycogen molecules

70
Q

What is Glycogenolysis?

A
  • Glycogen Breakdown
71
Q

Explain Glycogenolysis.

A

Glycogen Breakdown
- Glycogen breakdown to glucose
- occurs in high cellular activity with glucose depletion
- Requires Glycogen Phosphorylase

72
Q

What regulates Glycolysis?

A
  • Levels of substrate fructose 1,6-diphosphate
  • high oxygen inhibits
  • Concentration of 4 enzymes
73
Q

What 4 enzymes regulate Glycolysis?

A
  • Hexokinase
  • Phosphorylase
  • Phosphofructokinase
  • Pyruvate Kinase
74
Q

What anagram is used for remembering the 4 key enzymes that regulate glycolysis?

A

He - Hexokinase
Played - Phosphorylase
Poker - Phosphofructokinase
Poorly - Pyruvate Kinase

75
Q

If Pyruvate binds to acetyl-CoA is it reversible?

A
  • NO
76
Q

When would pyruvate irreversibly bind to acetyl-CoA and enter the citric acid cycle?

A
  • Abundance of Oxygen Present
77
Q

What happens during strenuous physical activity, when energy demands exceed oxygen supply?

A
  • The respiratory chain can’t process all hydrogen joined to NADH
78
Q

What is required for the continued release of anaerobic energy?

A
  • NAD+ to oxidize 3-phosphoglyceraldehyde
79
Q

How does NAD+ regenerate during anaerobic glycolysis? When would this be required?

A

How
- Pair of hydrogens combines with Pyruvate to form Lactate
When
- Energy demands exceed oxygen supply (strenuous physical activity)

80
Q

What are the steps of Lactate formation? What is required? Is it Reversible?

A

Steps
- 2 hydrogens combine pyruvate
- Catalyzed by lactate dehydrogenase
Required
- Lactate Dehydrogenase Enzyme
Reversible
- YES

81
Q

What happens to lactate formed from pyruvate?

A

Oxidized By:
- Neighbouring Muscle Fibers
- Heart
- Ventilatory Muscles
Indirect Precursor
- Liver Glycogen

82
Q

Where would lactate form during rest and moderate physical activity?

A
  • Red blood cells (no mitochondria)
  • Muscle fibers with high glycolytic activity, and low enzymes
83
Q

What happens once lactate forms in the in the muscle?

A

Two Routes:
- Diffuse in interstitial space/blood for buffering
- Provides Gluconeogenic substrate for glycogen synthesis

84
Q

What is Gluconeogenesis? What does it result in?

A

Metabolic pathway
- Generation of glucose from non-carbohydrate carbon substrates

85
Q

What are the two phases of Aerobic Glycolysis?

A

Phase 1
- Pyruvate from Glycolysis
Phase 2
- Electron Transport Chain

86
Q

What happens in Phase 1 of Aerobic Glycolysis?

A
  • Coenzyme A turns Pyruvate into Acetyl-CoA
  • Reduced coenzymes transfer hydrogen to the electron transport chain
87
Q

What happens in Phase 2 of Aerobic Glycolysis?

A
  • Reduced Coenzyme Complexes become oxidized
88
Q

What is the breakdown of ATP yield from Aerobic Glycolysis?

A

Yield
- 2 ATP Glycolysis
- 2 ATP Citric Acid Cycle
- 28 ATP Oxidative Phosphorylation

89
Q

How much energy does fat supply ?

A

30-80%

90
Q

What determines the amount of energy used from fat?

A
  • Nutritional Status
  • Level of Training
  • Intensity/Duration of Physical Activity
91
Q

What is the total energy reserve of fat in a young adult male?

A
  • 60-100k kcal in adipocytes
  • 3k kcal stored in intramuscular triacylglycerol
92
Q

What are three specific energy sources from fat catabolism?

A
  • Triacylglycerol stored in muscle mitochondria
  • Triacylglycerols in blood
  • free fatty acids in blood
93
Q

Where are circulating triacylglycerols in?

A
  • Lipoprotein Complexes
94
Q

Where do circulating free fatty acids come from?

A

Mobilized from triacylglycerol in adipose tissue

95
Q

What happens prior to energy being released from fat?

A
  • Hydrolysis in the cell’s cytosol splits triacylglycerol into glycerol and three fatty acids
96
Q

What is required for the triacylglycerol to split into glycerol ad three fatty acids?

A
  • Lipase Enzyme
97
Q

How many steps does it take for lipid mobilization?

A
  • 7 discrete steps
98
Q

What are the 7 discrete steps of lipid mobilization?

A
  1. Breakdown triacylglycerol to free fatty acid.
  2. Transport of Free fatty acids in the blood
  3. Uptake of free fatty acids from blood to muscle
  4. Preparation of fatty acids from blood to muscle
  5. Entry of activation fatty acids into muscle mitochondria
  6. Breakdown of fatty acid to acetyl-CoA via beta oxidation and production of NADH and FADH2
  7. Couple oxidation in citric acid cycle and electron transport chain
99
Q

How many ATP molecules does the complete oxidation of triacylglycerol molecules yield?

A
  • 460ATP (depends on # of carbons)
100
Q

What serves as the most plentiful source of potential energy?

A
  • Stored Fat
101
Q

When does fat become the primary energy fuel for exercise and recovery?

A

Intense, long-duration
- depletion of both blood glucose and muscle glycogen

102
Q

What is the breakdown of ATP Yield from the complete breakdown of a triacylglycerol?

A

3 Fatty Acids (18-carbon each)
- 147 ATP per
- 147 x 3 = 441
1 Glycerol
- 19 ATP
- 441 + 19 ATP = 460 ATP

103
Q

What pathways do fatty acids utilize for ATP synthesis?

A
  • B-oxidation
  • Citric Acid Cycle
104
Q

What pathways do glycerols utilize for ATP synthesis?

A
  • Glycolysis
  • Citric Acid Cycle
105
Q

What does it mean that “fat burns in a carbohydrate flame”?

A
  • Oxaloacetate required for citric acid cycle
  • Oxaloacetate breaks down over time
  • Glucose to Pyruvate can create more Oxaloacetate
  • Without Oxaloacetate, no break down of Fatty Acids
  • Without Pyruvate, no Oxaloacetate
106
Q

How do amino acids enter the energy pathway?

A

Deamination
- removal of nitrogen

107
Q

How do glucogenic amino acids contribute to energy?

A

When Deaminated
- yield intermediates for glucose synthesis

108
Q

How do Ketogenic amino acids contribute to energy?

A

When Deaminated
- yield intermediate actyl-CoA or acetoacetate for TAG formation

109
Q

What provides the vital link between macronutrient energy and chemical energy?

A
  • Citric Acid Cycle
110
Q

What are the metabolic interconversions between carbohydrates and other macronutrients?

A

Carbs to lipids
- lipogenesis
carbs to nonessential amino acids

111
Q

What are the metabolic interconversions between fats and other macronutrient substrates?

A

Lipids convert to nonessential amino acids

112
Q

What are the metabolic interconversions between proteins and other macronutrient substrates?

A

Protein convert to
- carbs
- Lipids

113
Q
A