Protein Metabolism Chap. 12

Question 1

What kinds of proteins are there in the body?

Answer 1

Enzymes and hormones
Motile and structural proteins
Transporters, carriers, receptors

Question 2

What kind of reaction is protein synthesis?

Answer 2

Anabolic reaction

Question 3

What kind of reaction is proteolysis?

Answer 3

Catabolic reaction

Question 4

What is proteolysis?

Answer 4

Protein degradation and breakdown

Question 5

What synthesizes proteins from mRNA?

Answer 5

Ribosomes

Question 6

What degrades proteins into its amino acid building blocks?

Answer 6

Proteases

Question 7

What marks proteins for degradation by proteasomes?

Answer 7

Ubiquination

Question 8

Ubiquination has marked a protein for degradation. What happens?

Answer 8

Ubiquitin is added to the protein

Question 9

What type of protein do proteases degrade in the stomach and small intestine? How?

Answer 9

Dietary protein

Proteases cleave specific peptide bonds in the protein

Question 10

Protein synthesis and proteolysis both continuously occur with:

Answer 10

Relative balance

Question 11

What happens to protein synthesis during hard resistance exercise?

Answer 11

Increased rate

Lasts 1-2 days

Question 12

What happens to protein synthesis during hard endurance exercise?

Answer 12

Decreased rate

This indicates a negative effect on muscle building.

Question 13

What is the effect of hard resistance exercise on proteolysis?

Answer 13

Increased, but to a lesser degree than protein synthesis

This indicates that while protein breakdown increases, it does not surpass the rate of synthesis.

Question 14

What happens to proteolysis during moderate to hard endurance exercise?

Answer 14

Increased rate

This suggests a higher breakdown of proteins during endurance activities.

Question 15

What is the net effect on protein levels immediately after exercise?

Answer 15

Net decrease in protein

This reflects the balance of increased proteolysis and decreased synthesis.

Question 16

What happens to protein metabolism hours after exercise terminates?

Answer 16

Protein synthesis overtakes proteolysis

Question 17

What is released in high levels from the gut and connective tissue following exercise?

Answer 17

Amino acids

Amino acids are essential for various physiological processes, including protein synthesis.

Question 18

How long do protein synthesis rates remain increased after exercise?

Answer 18

Four days

This increase in protein synthesis is crucial for recovery and adaptation.

Question 19

What specific protein is increased due to elevated protein synthesis after exercise?

Answer 19

Collagen

Collagen is important for maintaining the structural integrity of connective tissues.

Question 20

Most amino acids (AAs) in the body are incorporated in:

Answer 20

Proteins

Question 21

What percentage of free amino acids does Glutamine represent?

Answer 21

60%

Question 22

What percentage of free amino acids does Glutamate represent?

Answer 22

14%

Question 23

What percentage of free amino acids does Alanine represent?

Answer 23

4%

Question 24

60% of free AAs are:

Answer 24

Glutamine

Question 25

14% of free AAs are:

Answer 25

Glutamate

Question 26

4% of free AAs are:

Answer 26

Alanine

Question 27

The first step in catabolism for all amino acids is:

Answer 27

Deamination

Question 28

What enzyme accomplishes deamination?

Answer 28

Deaminase

Question 29

What does deaminase do?

Answer 29

Simple removal of amino group

Question 30

What is oxidative deamination?

Answer 30

Removal of amino group and electrons

Question 31

The removal of electrons and an amino group is known as:

Answer 31

Oxidative deamination

Question 32

What does transaminase do?

Answer 32

Transfers amino group from one compound to another

Question 33

Transferring an amino group from one compound to another is done by:

Answer 33

Transaminase

Question 34

When an amino group is transferred to another compound what is produced?

Answer 34

α-keto acids

Question 35

a-keto acids can be converted to:

Answer 35

Common metabolic pathway intermediates for oxidation

Question 36

What are the metabolic intermediates that AAs can be converted into?

Answer 36

Pyruvate Acetyl-CoA Acetoacyl-CoA α-ketoglutarate Succinyl-CoA Fumarate Oxaloacetate

Question 37

On average, the carbon skeleton of an oxidized AA will yield:

Answer 37

22 ATP

Question 38

What are gluconeogenic amino acids?

Answer 38

Amino acids that are converted to pyruvate or oxaloacetate for gluconeogenesis ## Footnote These amino acids serve as substrates for the production of glucose.

Question 39

What happens to certain amino acids during exercise?

Answer 39

They are converted to gluconeogenic substrates or CAC intermediates ## Footnote These intermediates can then be transformed into oxaloacetate.

Question 40

What hormone scenario occurs during exercise to increase gluconeogenic rate?

Answer 40

Increased levels of hormones such as glucagon and epinephrine ## Footnote These hormones promote gluconeogenesis in the liver.

Question 41

What are ketogenic amino acids?

Answer 41

Amino acids that are converted to Acetyl-CoA and Acetoacyl-CoA ## Footnote These compounds cannot be converted to glucose but can be used to produce ketone bodies.

Question 42

How many amino acids are gluconeogenic?

Answer 42

14 amino acids ## Footnote These amino acids can contribute to glucose synthesis.

Question 43

How many amino acids are ketogenic?

Answer 43

2 amino acids ## Footnote These amino acids are specifically converted to ketone bodies.

Question 44

How many amino acids are both gluconeogenic and ketogenic?

Answer 44

4 amino acids ## Footnote These amino acids can serve dual roles in metabolism.

Question 45

Fill in the blank: Acetyl-CoA and Acetoacyl-CoA can't become _______.

Answer 45

glucose ## Footnote These compounds are instead utilized for ketone body production.

Question 46

AAs from the muscle are available for gluconeogenesis in the liver due to the:

Answer 46

Glucose-Alanine Cycle

Question 47

Pyruvate and glutamate will make:

Answer 47

α-ketoglutarate and alanine This reaction is reversible

Question 48

High concentrations of ammonia are:

Answer 48

Toxic to the brain

Question 49

At moderate intensity exercise, _____ is/are the main source of ammonia.

Answer 49

Amino Acids

Question 50

At high intensity exercise, _____ is/are the main source of ammonia.

Answer 50

AMP

Question 51

During high-intensity exercise, AMP makes ammonia. Why?

Answer 51

Anaerobic glycolysis ATP -> ADP -> AMP Excess AMP is degraded by AMP deaminase which produces ammonia

Question 52

How do we get rid of ammonia in the body?

Answer 52

The Urea Cycle

Question 53

What is the point of the urea cycle?

Answer 53

To remove ammonia