Amino Acid Degradation & The Urea Cycle (Ch 30)

Question 1

What does pepsin do?

Answer 1

breaks proteins into smaller oligopeptides

Question 2

pH of stomach acid

Answer 2

1-2

Question 3

Puprose of Bile Salts

Answer 3

aids in breakdown of fatty acids

Question 4

Which organ releases NaHCO3 (sodim bicarbonate)?

Answer 4

pancreas

Question 5

Why does the pancreas release NaHCO3?

Answer 5

neutralizes the acidic pH of food that has just left the stomach

Question 6

Aspartic Acid AKA

Answer 6

Aspartate (Asp)

Question 7

Glutamic Acid AKA

Answer 7

Glutamate (Glu)

Question 8

In Oxidative Deamination, Glutamate reacts with Water and NAD+ to form what 4 products?

Answer 8

alpha-ketoglutarate
NADH
NH4+
H+

Question 9

Describe the purpose of the Urea Cycle

Answer 9

The urea cycle removes toxic NH4+ produced during oxidative deamination by converting it into urea which can be excreted.

Question 10

What is the simple formula describing the Urea Cycle?

Answer 10

NH4+ –> Urea

Question 11

Describe the 5 Steps of the Urea Cycle to convert NH4+ into Urea

Answer 11

1) Bicarb is phosphorylated and aminated to form Carbamoyl Phosphate
2) Orthinine binds to Carbamoyl Phosphate to form Citrulline
3) Citrulline reacts w/ Asp to form Arginosuccinate
4) Arginosuccinate is broken apart to form Arginine and Fumarate
(fumarate can be converted to malate then oxaloacetate)
5) Arginine is used in protein synthesis OR is hydrolyzed to form Urea (which is excreted) and Orthinine (which can bind more carbamoyl phsopahte to continue the cycle)

Question 12

Oxaloacete can be used in which two processes?

Answer 12

The Citric Acid Cycle
Gluconeogenesis

Question 13

Fumarate –> ______ —> Oxaloacetate

Answer 13

Malate

Question 14

What product is simultaneously produced with urea?

Answer 14

orthinate

Question 15

Which amino acid is broken down to form urea?

Answer 15

Arginine (Arg)