Integration of Metabolism

Question 1

Define homeostasis.

Answer 1

Metabolic condition that is the result of dynamic processes to maintain a constant internal environment despite a changing external environment

Question 2

Define negative feedback.

Answer 2

Acts to resist any deviation

Question 3

Define metabolism.

Answer 3

Sum of anabolic and metabolic processes, both act at the same time

Question 4

Which metabolic process requires E?

Answer 4

Anabolism

Question 5

Which metabolic process yields E?

Answer 5

Catabolism

Question 6

Pyruvate -> AA
and TCA -> AA
are only for what?

Answer 6

Nonessential amino acids

Question 7

Which AA are glucogenic? Ketogenic?

Answer 7

Glucogenic: AA that can make glucose via pyruvate or TCA cycle intermediates
Ketogenic: AA that are degraded to acetyl CoA

Question 8

What happens during the fed state?

Answer 8

Carbs -> Glucose -> Liver and muscle glycogen OR body fat stores
Fat -> Fatty acids -> body fat stores
Protein -> amino acids -> N lost in urine OR body fat stores

Question 9

What happens during a short-term fast?

Answer 9

Glycogen in liver -> Glucose -> Energy

Body fat stores -> Fatty acids -> Energy

Question 10

What happens to glycogen after 24 hours?

Answer 10

Depleted

Question 11

What promotes protein breakdown?

Answer 11

Glucagon

Question 12

What are the 4 ways to make E during a long term fast?

Answer 12

1) Body protein -> amino acids -> glucose ->E
2) Body protein -> amino acids -> ketone bodies -> E
3) Body fat -> fatty acids -> ketone bodies -> E
4) Body fat -> fatty acids -> E

Question 13

What are the 2 ways to produce ketone bodies?

Answer 13

Amino acids -> ketone bodies

Fatty acids -> ketone bodies

Question 14

What is lost in urine during a long term fast?

Answer 14

N and some ketone bodies lost in urine

Question 15

Ketone bodies are produced from what in the absence of glucose?

Answer 15

Fatty acid oxidation

Question 16

How do you form acetoacetate?

Answer 16

Condensation of acetyl CoA and the removal of the CoA to form a compound that is converted to acetoacetate

Question 17

What can acetoacetate do? What are its downsides?

Answer 17

• Fuel the brain since its water soluble

- BUT acidosis

Question 18

What does TCA need to keep spinning? What happens if not?

Answer 18

• Pyruvate (3 carbons)

- If not, acetyl coa builds up -> ketone bodies

Question 19

What cannot produce glucose?

Answer 19

Fatty acids

Question 20

How can ketone bodies become other ketones?

Answer 20

• Lose a CO2 (acetone)

- May add 2 hydrogens (beta-hydroxybutyrate)

Question 21

What is the RQ for anabolism, short-term and long-term fast?

Answer 21

Anabolism: RQ = 1 (glucose)
Short-Term: RQ = 0.8 (balance of FA and glucose)
Long-Term: RQ = 0.7 (predominantly fatty acids -> acetyl CoA)

Question 22

What is a ketogenic diet?

Answer 22

VERY low in CHO to promote fatty acid oxidation in absence of glucose

Question 23

Ketogenic diets are treatments for what?

Answer 23

Epilepsy in kids

Question 24

What is glycolysis?

Answer 24

Glycolysis: Glucose to Pyruvate

Question 25

What can pyruvate be converted to anaeorobically? Aerobically?

Answer 25

Anaerobically (no O): lactate

Aerobically (with O): acetyl CoA

Question 26

What can be used to make glucose? What can’t?

Answer 26

Can: Pyruvate and lactate

Can’t: acetyl CoA

Question 27

What happens before an amino acid enters metabolic pathways?

Answer 27

Deamination: nitrogen containing amino group = removed

Question 28

What do carbohydrates yield? Where does it go?

Answer 28

Yield: glucose
Go: stored as glycogen, some is broken down to pyruvate and acetyl CoA

Question 29

What does the digestion of fat yield? Where does it go?

Answer 29

Yield: fatty acids and glycerol
Go: some are stored as body fat, others are broken down to acetyl coa

Question 30

What does the digestion of protein yield? Where does it go?

Answer 30

Yield: amino acids
Used: build body protein, some are broken down to acetyl CoA, while the carbon skeleton of others enters the TCA cycle directly

Question 31

What can acetyl CoA do?

Answer 31

• Enter the TCA cycle to release energy

- Combine with other molecules of acetyl coa to make body fat

Question 32

Which nutrients can make acetyl coa?

Answer 32

all of them

Question 33

What is the main characteristic of the pathway from pyruvate to acetyl CoA?

Answer 33

It is metabolically irreversible