Amino Acid fate etc.

Question 1

What are essential amino acids?

Answer 1

We can only get them through our diet. Body cannot synthesise them.

Question 2

What levels of amino acids are excreted?

Answer 2

Very low levels.

Question 3

What is the rate of turnover of proteins in the liver cells?

Answer 3

Very high turnover rate, synthesised and broken down quickly.

Question 4

What are the 2 main processes involved with Amino acid catabolism in the liver?

Answer 4

1. removal and excretion of amino group (transamination and deamination).
2. Oxidation of carbon skeleton.

Question 5

What tissue in the body can deal with ammonia produced by amino acid?

Answer 5

Liver is the only tissue.

Question 6

Where does the Urea cycle occur?

Answer 6

In the Liver.

Question 7

Where does transamination and deamination occur?

Answer 7

Kidneys and Liver.

Question 8

What is the general purpose of transamination?

Answer 8

Use one amino acid to make another amino acid.

Question 9

In terms of energy, what are the 2 types of amino acids?

Answer 9

Glucogenic (can enter Gluconeogeneis) and ketogenic (can convert into ketone bodies)

Question 10

What happens to the amino group of one amino acid?

Answer 10

It gives it’s amino group to ALPHA-keto glutarate.

Question 11

What happens to the amino acid that donates it’s amino group?

Answer 11

It becomes an ALPHA-keto acid.

Question 12

What happens to the ALPHA-keto glutarate that accepts the amino group?

Answer 12

It becomes L-glutamate.

Question 13

What enzyme catalyses the transamination reactions?

Answer 13

Transaminase/Aminotransferases.

Question 14

What cofactor does Transaminase need?

Answer 14

Pyridoxal Phosphate.

Question 15

Where is the cofactor derived from?

Answer 15

B group Vitamin pyridoxine.

Question 16

What is the function of glutamate after it accepts amino groups?

Answer 16

It acts as an amino group donor for biosynthetic pathways or excretion pathways that lead to the elimination of nitrogenous waste products.

Question 17

What are common amino acids that undergo transamination and deamination?

Answer 17

Glutamine from other tissues and Alanine from muscles.

Question 18

What is the main reason for deamination?

Answer 18

Way to get rid of toxic ammonia in the body.

Question 19

What happens to L-glutamate?

Answer 19

The L-glutamate has it’s ammonia cleaved off.

Question 20

What enzyme acts on L-glutamate during demaination?

Answer 20

Glutamate Dehydrogenase.

Question 21

What happens to the ammonia?

Answer 21

It must enter the urea cycle and be converted to urea before being excreted.

Question 22

Why is the ammonia converted into another substance?

Answer 22

Ammonia is toxic for our cells.

Question 23

Is Ammonia very water soluble?

Answer 23

No.

Question 24

What are properties of urea?

Answer 24

Safe, water soluble, non-toxic.

Question 25

Why is urea good in the urine.

Answer 25

It is ore water soluble, so less water is excreted.

Question 26

Structure of urea?

Answer 26

2 amino groups/N atoms.

Question 27

Where does the urea cycle function?

Answer 27

Liver.

Question 28

What pathway produces urea?

Answer 28

Urea cycle.

Question 29

Where does the first Nitrogen for the urea cycle come from?

Answer 29

Ammonia produced from glutamate during deamination enters urea cycle as carbamoyl phosphate.

Question 30

What is the source of the second Nitrogen atom?

Answer 30

Aspartate, an amino acid.

Question 31

Energy requirements of Urea cycle?

Answer 31

Endergonic reaction, needs 3 ATP for every urea molecule produced.

Question 32

Energy production?

Answer 32

Fumarate goes into CAC via being converted into Malate. 1 NADH and 2.5 ATP is produced.

Question 33

Why could there be excess ammonia in the blood?

Answer 33

1. Liver damage. 2. Deficiency in urea cycle enzymes. 3. High-protein diets.

Question 34

Symptoms of excess ammonia in blood?

Answer 34

Person appears drunk because ammonia can cross blood brain barrier.

Question 35

Where does ketogenesis occur?

Answer 35

In the Liver.

Question 36

What are ketones made from?

Answer 36

Acetyl CoA.

Question 37

What diet stimulates Ketogenesis?

Answer 37

High fat/low carb diet.

Question 38

What are the 3 main ketones?

Answer 38

Acetone, Acetoacetate, BETA-hydroxyl-butyrate

Question 39

What is the major site of metabolism of drugs and toxic compounds?

Answer 39

Liver.

Question 40

What is the first phase of drug metabolism in the Liver?

Answer 40

Modification.

Question 41

What happens in Phase 1 of drug metabolism in the Liver?

Answer 41

Toxin or drug is oxidised, reduced, or hydrolysed.

Question 42

What happens to the properties of the drug after phase 1?

Answer 42

It becomes more hydrophilic /polar and also more reactive (volatile).

Question 43

What is phase 2 of drug and toxin metabolism?

Answer 43

Conjugation.

Question 44

What happens in phase 2 of of drug metabolism in the Liver?

Answer 44

Polar functional groups are added on to make the compound more soluble and less reactive. Able to be excreted in urine.