Amino acid catabolism

Question 1

Amino acids can be stored (T/F)

Answer 1

False, amino acids CANNOT be stored

Question 2

Proteins/amino acids have a half life (T/F)?

Answer 2

True

Question 3

Why do amino acids have to be oxidatively degraded? (3)

Answer 3

Protein turnover (don’t want all amino acids active at the same time)

High protein diet (excess amino acids)

Starvation/diabetes (When you don’t have enough glucose or energy in the body, body starts breaking down A.A.’s for energy)

Question 4

What cells in your stomach produce HCL?

Answer 4

Parietal cells

Question 5

How is pepsinogen autoproteolytic?

Answer 5

It converts itself into pepsin (at low pH)

Question 6

When protein enters the stomach, what is the first hormone released?

Answer 6

Gastrin

Question 7

What does gastrin stimulate the release of?

Answer 7

Pepsinogen and HCL

Question 8

Low pH in the small intestine triggers the release of _______(hormone) in _______ (in the body)?

Answer 8

Secretin in the blood which causes the release of bicarbonate (HCO3) to neutralize the low pH

Question 9

What hormone causes the release of zymogens? From ______ (in body) to the _______ (in body)?

Answer 9

Cholecystokinin triggers the release of zymogens from the pancreas into the small intestine

Question 10

Why are zymogens inactive in the pancreas?

Answer 10

If they were active, they would chew up the pancreas.

Question 11

We synthesize digestive enzymes as inactive precursors. Name 2 inactive digestive enzymes and what their active forms are.

Answer 11

Trypsinogen –> Trypsin

Chymotrypsinogen –> alpha=chymotrypsin

Question 12

What happens if trypsin gets loose into the pancreas?

Answer 12

The pancreas can release a pancreatic trypsin inhibitor

Question 13

Amino acids (Ala, Glu, Gln, Asp) can be readily converted into CAC intermediates (T/F)?

Answer 13

True!

Question 14

PLP is a Schiff base (T/F)

Answer 14

True

Question 15

What is the alpha-keto acid that corresponds with alanine?

Answer 15

Pyruvate

Question 16

What is glutamate’s alpha keto acid?

Answer 16

alpha ketoglutarate

Question 17

What is Aspartate’s alpha ketoacid?

Answer 17

Oxaloacetate

Question 18

It doesn’t take energy to ass an amine (NH4) group (T/F)

Answer 18

False, it takes a lot of energy to add an amino group (at least 1 ATP)

Question 19

Where does the urea cycle occur?

Answer 19

Half of it occurs in the mitochondria, half in the cytocol

Question 20

What regulates Carbomyl P Synthase 1?

Answer 20

Arginine. A build-up of arginine will positively increase the activity of Carbomyl synthase

Question 21

How much energy does it take to convert citrulline to argininosuccinate?

Answer 21

3 ATP

Question 22

All amino acids become CAC intermediates (T/F)?

Answer 22

True

Question 23

What happens to CAC intermediates? (3)

Answer 23

1. diverted to gluconeogenesis (formation of glucose)
2. Diverted to ketogenesis (formation of ketone bodies)
3. Completely oxidized to CO2 and H2O

Question 24

Metabolic pathways for amino acids are not distinct (T/F)?

Answer 24

True!

Question 25

What are 2 precursors to glucose?

Answer 25

Pyruvate and oxaloacetate

Question 26

What’s the difference between ketogenic and glucogenic amino acids?

Answer 26

glucogenic A.A. encourage the precursors of glucose (pyruvate and oxaloacetate)

ketogenic A.A. encourage the precursors of ketone bodies / fatty acids

Question 27

What is Phenylketonuria?

Answer 27

Phenylketonuria is a mutation in Phenylalanine hydroxylase. It causes phenylalanine and phenylpyruvate in the blood. These are excreted through the urine.