Unit 4 and Course Review

Question 1

What enzyme is regulated by N-Acetyl Glutamate (NAGs)?

Answer 1

CPS 1

Question 2

What AA is considered non-essential because it is generated by the Urea cycle?

Answer 2

Arginine

Question 3

The reaction of freee ammonia with alpha-ketoglutarate is catalyzed by _____ and requires _____ as a reactant.

Answer 3

Glutamate Dehydrogenase (GDH)

NADH or NADPH

Question 4

Transamination of all AA requires what cofactor?

Answer 4

PLP (Pyridoxal Phosphate)

Question 5

What enzyme will be the first initiator that activates all the pancreatic zymogens required for protein digestion?

Answer 5

Enteropeptidase

Question 6

Pepsinogen is activated by what mechanism(s)?

Answer 6

Change in pH (high Acidity HCL in stomach)
or
Autocleavage

Question 7

When is the process of autophage most likely occurring within the cell?

Answer 7

When there is low energy in the cell: ratio of AMP/ATP is greater than 1

Question 8

mTOR pathway is related to the process of autophagy. When mTOR is active, this is most consistent with what in regards to autophagy?

Answer 8

Autophagy is inhibited

Question 9

A deficiency in which of the following enzymes will not result in an increase in orotic acid?

1. Arginosuccinate lyase
2. Arginosuccinate synthetase
3. N-Acetylglutamate
4. Ornithine transcarbamolayse

Answer 9

3. N-Acetylglutamate (will only effect lack of Carbamoyl phosphate synthesis due to lower output from CPS 1)

Question 10

Which of the following will contribute to elevated Triglycerides in individuals with Type 2 Diabetes?

1. Increased Glycolysis
2. Decreased Beta-oxidation
3. Reduced activity of LPL
4. Increased activity of PPP

Answer 10

3. Reduced activity of Lipoprotein lipase
   - if insulin sensitivity is lacking, LPL activity will be reduced, this will result in a decrease in TG storage and increase in circulation levels

Question 11

Alanine can be shuttled from the skeletal muscle to the liver where it is deaminated by what enzyme ?

Answer 11

Alanine aminotransferase

Question 12

The primary role of glutamine in the brain is to provide substrate for the synthesis of which following compounds?

1. Glutamate
2. Neurotransmitters
3. BCAAs
4. Urea

Answer 12

2. Neurotransmitters

Question 13

During exercise, the pathways of ______ and ______ are integrated as means of providing energy and reducing NH4+ levels.

Answer 13

BCAA catabolism and Purine Degradation

Question 14

Which GLUT transporter facilitates glucose uptake in skeletal muscle?

Answer 14

GLUT 4

Question 15

In the case of an individual in a sedentary lifestyle eating a diet consisting of 50%carbs, 30% protein, 20% fat, this individual would be in ________ nitrogen balance.

Answer 15

Neutral

Question 16

Glutamine is metabolized to bicarbonate ion in the ______ to replenish this important component of the blood buffering system.

Answer 16

Kidneys

Question 17

True or False:

The Pool of AA is strictly controlled, similar to blood glucose.

Answer 17

False

Question 18

Under fasting conditions what will the liver transition to the use of for energy?

Answer 18

Fatty acids (not ketones)

Question 19

True or False:

GNG and Beta Oxidation are coupled. Beta oxidation helps facilitate GNG by providing Acetyl CoA as substrate for GNG

Answer 19

False- They are coupled but Actetyl CoA can not be a substrate for GNG
-it is only for allosteric activation of Pyruvate Carboxylase required for GNG (makes Pyruvate into OAA)

Question 20

What can a deficiency in pyruvate carboxylase do ?

Answer 20

prevents GNG from occurring as Pyruvate is not coverted to OAA
- instead excess goes to make excess lactate

Question 21

Release of ACTH , from the pituitary, can be inhibited by which hormone?

Answer 21

Cortisol (from adrenal cortex)

Question 22

What two things can inhibit the release of GH from the anterior pituitary?

Answer 22

Somatostatin

IGF-1

Question 23

When cortisol is elevated, _____ _______ synthesis is enhanced.

Answer 23

Hepatic protein

protein translation

Question 24

Exams can be stressful and elicit release of Cortisol. This will help the body maintain supply to your brain of glucose by decreasing ____ _____ in the skeletal muscle.

Answer 24

glucose uptake

Question 25

In a patient with DECREASED secretion of Growth Hormone due to a pituitary tumor, there would be an ______ _______ from hypothalamus, and ______ _____ secretion from the liver.

Answer 25

increased GHRH

Diminished IGF-1

Question 26

Within the pancreas, somatostatin (delta cells) inhibits the release of ____ from Alpha cells.

Answer 26

Glucagon

Question 27

In an individual with a pituitary tumor that leads to increase in cortisol secretion from adrenal gland, both _____ and ____ would be elevated .

Answer 27

ACTH and Cortisol
(Figure 43.7)

-because the ACTH is abnormally secreted by tumor to stimulate more cortisol and cancelling out inhibition is happening by the cortisol on the pituitary

Question 28

_____ is required for muscle and fat cells to synthesize and release lipoprotein lipase to bind to the capillary walls. In the abscence of this hormone, LPL what will occur?

Answer 28

Insulin

TG would be elevated in blood due to reduced removal from cholymicrons and VLDL

Question 29

A patient with ornithine transcarbamoylase deficiency exhibits orotic aciduria, this occurs due to the bypassing the regulated step of de novo _______ synthesis because elevated ______ ______ will escape the MT and bypass the regulation of CPS-2 to make it anyways.

Answer 29

Pyrimidine

Carbamoyl Phosphate

Question 30

Activation of FA requires a two step reaction. In the first _____ donates AMP to form a covalent bond with the _______ ___ of the FA, releasing Pyrophosphate.

Answer 30

ATP

Carboxylic Acid

Question 31

In the second step of FA activation, _____ ___ displaces the AMP on the Carboxylic acid , forming ______ _____.

Answer 31

Coenzyme A

Fatty-acyl CoA

Question 32

Of BCAAs leucine, isoleucine, and Valine, only ____ and _____ can be converted to glucose in the liver. ____ is strictly ketogeneic and cannot generate glucose.

Answer 32

Valine and Isoleucine

Leucine

(high abundance of these BCAAs in proteins so play important role in whole body amino acid metabolism)

Question 33

Pepsinogen at a neutral pH is folded that promotes ionic interactions between AA side chains. After a meal when pH drops to 2.0 it will unfold due to what?

Answer 33

Protonation of carboxylic acid side chains (their pKa is abou 4.0- so when pH of stomach is 2.0 they will be protonated)