Lecture 35: Integration of Metabolism Flashcards

1
Q

What are the possible fates of glucose-6-phosphate?

A

Glycogen, pyruvate, ribose-5-phosphate

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2
Q

What are the possible fates of pyruvate?

A

Acetyl CoA, lactate, alanine, oxaloacetate

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3
Q

What are the posisble fates of Acetyl CoA?

A

CO2, Fatty acids, ketone bodies

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4
Q

What is the function of the pancreas during metabolism?

A

Secretes insulin and glucagon in response to changes in blood glucose concentration

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5
Q

What is the function of the lymphatic system during metabolism?

A

Carries lipids from intestine to liver

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6
Q

What is the function of the portal vein during metabolism?

A

Carries nutrients from intestine to liver

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7
Q

What is the function of the small intestine during metabolism?

A

Absorbs nutrients from the diet, moves into blood or lymphatic system

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8
Q

What is the function of skeletal muscle during metabolism?

A

Uses ATP to do mechanical work

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9
Q

What is the main organ involved in metabolism?

A

Liver

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10
Q

What does the liver use for its own energy needs?

A

beta-oxidation of fatty acids

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11
Q

Which of the following is false about the metabolism of the liver?

A. It processes most, but not all, dietary amino acids
B. The presence of G6P makes the liver uniquely able to release glucose from glycogen into the bloodstream
C. It synthesizes most of the urea produced in the body
D. It normally fuels the body by releasing its fat stores during fasting
E. One of its major jobs is to provide fuels for the brain

A

D. It normally fuels the body by releasing its fat stores during fasting

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12
Q

What hormones signal the release of fatty acids and glycerol from adipose tissue?

A

Glucagon, epinephrine

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13
Q

How does skeletal muscle use energy on an immediate, short-term, and long term basis?

A

Immediate: ATP
Short-term: Glycolysis
Long-term: Oxidative system

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14
Q

What is the phosphagen system?

A

Used under anaerobic conditions during bursts of heavy activity; ATP is immediately exhausted and replenished by phosphocreatine

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15
Q

What percentage of total O2 consumed by a resting human does the brain use?

A

20%

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16
Q

What type of energy does the brain utilize under prolonged conditions of low glucose?

A

Ketone bodies

17
Q

What does the heart use for fuel?

A

Circulating fats

18
Q

Which of the following pathways is inhibited by the action of insulin?

A. Glycolysis
B. Kerb's cycle
C. Gluconeogenesis
D. Glycogen synthesis
E. Fatty acid synthesis
A

C. Gluconeogenesis

19
Q

What are some metabolic effects of insulin?

A

Increase in glucose uptake, glycogen synthesis, glycolysis, fatty acid synthesis; decrease in glycogen breakdown

20
Q

What type of receptor is the insulin receptor and what does it do?

A

Receptor tyrosine kinase; phosphorylates tyrosine

Long term process by gene expression, immediate process by movement of GLUT4 to membrane

21
Q

What are some metabolic effects of epinephrine?

A

Increase of glycogen breakdown, gluconeogenesis, glycolysis, FA mobilization, glucagon secretion; decrease in glycogen synthesis, insulin secretion

22
Q

What type of receptors does epinephrine use?

A

G protein coupled receptors

23
Q

What are some metabolic effects of glucagon?

A

Increase glycogen breakdown, gluconeogenesis, fatty acid mobilization, ketogenesis; decrease in glycogen synthesis, glycolysis

24
Q

What type of receptors does glucagon use?

A

G protein coupled receptors

25
Q

What occurs in the liver in the fed state and fasting state?

A

Fed: Fatty acid synthesis
Fasting: Gluconeogenesis, FA oxidation, Ketone body synthesis

26
Q

What occurs in adipose tissue in the fed state and fasting state?

A

Fed: Fatty acid synthesis
Fasting: Fatty acid oxidation, triglyceride breakdown (fat being broken down for use)

27
Q

What occurs in muscle in the fed state and fasting state?

A

Fed:Glycogen storage
Fasting: Fatty acid oxidation, ketone body utilization (burn glycogen stores, then use ketones)

28
Q

What causes alcoholic fatty liver disease?

A

Excess energy in NADH due to alcohol consumption causes DHAP to be used for fatty acid synthesis

29
Q

What is the cellular energy sensor, and what occurs with this sensor when ATP is high or low?

A

AMPK

  1. ATP high, AMPK inactive
  2. ATP low, AMPK allosterically activated and phsophorylates targets
30
Q

Leptin

A

Released from fat, signals “full” feeling to hypothalamus; leptin resistance may be a factor in obesity

31
Q

Sirtuin

A

Pro-survival protein that is upregulated during caloric restriction and exercise due to NAD+; may contribute to longevity

32
Q

What is the rate limiting enzyme in the NAD+ salvage pathway?

A

NAMPT