Ch. 12: Bioenergetics & Regulation of Metabolism Flashcards

1
Q

what kind of systems are biological systems

A

open systems

can exchange energy and matter with the environment

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2
Q

what is the quantity of interest when determining changes of internal energy for living systems

A

heat

pressure and volume of living systems remains constant

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3
Q

what kinds of reactions have negative deltaG

A

spontaneous rxns in the forward direction, net loss of free energy

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4
Q

what kinds of reactions have positive deltaG

A

non spontaneous rxns, net gain of energy

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5
Q

when is deltaG zero

A

as the reaction approaches equilibrium

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6
Q

what are conditions in the modified standard state

A

[H+] = 10^-7 and pH = 7

delta G —> delta G’

@ 1M most con’c of protons would have pH 0

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7
Q

why is ATP a good energy carrier

A

high energy phosphate bonds

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8
Q

where is ATP produced

A

MOST –> ATP synthase in the mitochondria

SOME –> glycolysis and citric acid cycle

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9
Q

common involvement of ATP in coupled reactions

A

ATP hydrolysis

unfavorable movement across one gradient (like Na+ and K+) is coupled with the release of energy from ATP Hydrolysis

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10
Q

what occurs during ATP cleavage

A

high-energy phosphate group is transferred from ATP to another molecule, generally activating/inactivating the large molecule in a phosphoryl group transfer

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11
Q

what are high-energy electron carriers

A

NADH, NADPH, FADH2, ubiquinone, cytochromes, glutathione

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12
Q

what are flavoproteins

A

nucleic acid derivatives that contain a modified vitamin B12 and function as

  • electron carriers in the mitochondria
  • vitamin B activators
  • coenzymes for fatty acid oxidation, pyruvate decarboxylation, and glutathione reduction
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13
Q

what is homeostasis

A

physiological tendency toward a stable state that is maintained and adjusted, often with the expenditure of energy

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14
Q

what is the difference between homeostasis and equilibrium

A

equilibrium is fixed and does not allow for storage or mobilization … not desirable in a constantly changing external environment

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15
Q

when is the postprandial state occur

A

absorptive/well-fed state

occurs shortly after eating

  • –> greater anabolism (biomolecule synthesis) and food storage
  • –> nutrients to gut, liver, stored or distributed
  • –> blood glucose increase, insulin increase
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16
Q

what does insulin promote

A

glucose increase, insulin increase

  • glycogen synthesis in liver and muscle (until filled)
  • –> then liver converts excess to fatty acids/triacylglycerols
  • glucose entry + triacylglycerol synthesis in adipose
  • glucose entry + protein synthesis in muscle
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17
Q

what cell types are insensitive to insulin

A
red blood cells (use glucose anaerobically regardless of metabolic state)
nervous system (oxidize glucose to CO2 and H2O regardless of metabolic state)
18
Q

what are counterregulatory hormones

A

hormones that oppose the actions of insulin

glucagon, cortisol, epinephrine, norepinephrine, growth hormone

19
Q

when does the post absorptive state occur

A

fasting state

  • glucagon stimulates glycogen degradation in the liver releases glucose into the blood (5+ hours after eating)
  • glucagon stimulates hepatic gluconeogenesis (12+ hours after eating)
  • epinephrine stimulates amino acid (muscle) and fatty acid (adipose) release, transport to liver, and transformation for gluconeogenesis
20
Q

when doe the prolonged fasting state occur

A

starvation, 24+ hours

  • high levels glucagon and epinephrine
  • –> glycogen stores depleted
  • –> rapid lipolysis –> acetyl coA –> ketone bodies –> brain
  • –> gluconeogenic activity
21
Q

what kind of hormone is insulin

A

peptide hormone, water soluble

22
Q

how does insulin (and other hormones) regulate metabolism across the entire organism

A

peptide hormone –> rapidly adjust metabolic processes via second messenger cascades

23
Q

what cells secrete insulin

A

beta cells in the pancreas

24
Q

what tissues do not alter glucose uptake in response to insulin

A
  • nervous tissue
  • kidney tubules
  • intestinal mucosa
  • red blood cells
  • beta cells of the pancreas
25
what is the primary controller of insulin secretion
plasma glucose (high levels activate, low levels deactivate)
26
what cells secrete glucagon
alpha cells in the pancreas
27
what is the primary target of glucagon
hepatocytes - -> increases glycogenolysis - -> increases gluconeogeneis - -> increases liver ketogeneis, decreased lipogenesis - -> increased lipolysis
28
what is the primary controller of glucagon secretion
plasma glucose (low levels activate, high levels deactivate)
29
why are glucocorticoids part of the stress response
glucose must rapidly be mobilized during a stress response
30
what are catecholamines
epinephrine (adrenaline) norepinephrine (noradrenaline) - increase metabolic function associated with an adrenaline rush
31
thyroid hormones influence the metabolism of what molecules
lipids and carbohydrates
32
how do thyroid hormone levels fluctuate with metabolic state
thyroid hormones levels are relatively constant regardless of metabolic state, have long acting effects
33
what fuel does the liver use
well fed: glucose and amino acid | fasting: fatty acids
34
what fuel does the rising skeletal muscle use
well fed: glucose | fasting: fatty acids, ketones
35
what fuel doe the cardiac muscle use
well fed: fatty acids | fasting: fatty acids, ketones
36
what fuel does the adipose tissue use
well fed: glucose | fasting: fatty acids
37
what fuel does the brain use
well fed: glucose | fasting: glucose (ketones in prolonged fast)
38
what fuel do red blood cells use
well fed: glucose | fasting: glucose
39
what are the major roles of the liver in metabolism
- maintain constant level of blood glucose | - synthesize ketones when fatty acids are oxidized
40
how are mass and basal metabolic rate related
directly proportional with mass being the dependent factor when mass increases, rate increases
41
what hormones increase appetite
gherkin and orexin
42
what hormones increase satiety
leptin