Nitrogen - w5

Question 1

How do amino acids get absorbed from the lumen of the intestines into the bloodstream?

Answer 1

Na+-dependent transporters (secondary active transporters)

Question 2

How do amino acids get transported out of the cell?

Answer 2

facilitated diffusion

Question 3

How do amino acids get transported from the blood into the cells?

Answer 3

Na+ dependent (secondary active)

Question 4

Which enzymes on the brush border break down oligopeptides?

Answer 4

pancreatic enzymes

Question 5

What tells us how long a protein can function in the body?

Answer 5

the half life

Question 6

From where can we generate our intracellular amino acid pool?

Answer 6

dietary protein and protein degradation

Question 7

What are the proteases in lysosomes that are activated at low pH?

Answer 7

cathepsins

Question 8

What are the two steps in the ubiquitin-proteasome pathway?

Answer 8

ubiquitin tags proteins for degradation, proteasome complex degrade the proteins

Question 9

Proteins with regions rich in what are more likely to be degraded?

Answer 9

PEST (proline, glutamate, serine, threonine)

Question 10

Other than proteins, what else can amino acids be converted into?

Answer 10

carbohydrate (glycogen) or fat (triacylglycerols) ; as storage

Question 11

What process are amino acids important in formation?

Answer 11

gluconeogenesis

Question 12

What do you call the removal of an a-amino group?

Answer 12

transamination

Question 13

Transamination transfers the amino group from the og amino acid to a-ketoglutarate forming what?

Answer 13

glutamate

Question 14

What is the co-factor that helps to catalyze almost every amino acid reaction?

Answer 14

pyridoxal phosphate (PLP)

Question 15

In what vitamin can we get PLP?

Answer 15

Vitamin B6

Question 16

Where does oxidative deamination occur (liberation of ammonia)?

Answer 16

liver and kidneys

Question 17

What catalyzes the oxidative deamination of glutamate?

Answer 17

glutamate dehydrogenase

Question 18

What is the allosteric regulator of glutamate dehydrogenase?

Answer 18

ATP

Question 19

What is the most abundant AA in blood and is essential for ammonia transport?

Answer 19

glutamine

Question 20

What is the molecular structure of ammonia?

Answer 20

NH3+

Question 21

What makes up glutamine with the help of ATP?

Answer 21

glutamate + NH3

Question 22

In the liver, how does glutamine get broken back down to glutamate and NH3?

Answer 22

with the help of water (hydrolase)

Question 23

What enzyme takes NH3 from glutamine and changes pyruvate to alanine?

Answer 23

alanine aminotransferase

Question 24

Where is urea produced?

Answer 24

the liver (first two reactions in the mitochondria, rest in cytoplasm)

Question 25

What two molecules make up urea/

Answer 25

NH3 + CO2

Question 26

Where does 10% of urea end up?

Answer 26

in the intestine, cleaved by bacterial urease (splitting the CO2), NH3 is excreted in stool

Question 27

What is the disease of an accumulation of urea in the kidneys?

Answer 27

uremia

Question 28

What can hyperammonemia cause?

Answer 28

neurotoxicity, brain swelling, coma

Question 29

A genetic deficiency of what enzyme most commonly causes hyperammonemia?

Answer 29

ornithine transcarbamylase (OTC)

Question 30

What are some treatment for hyperammonemia?

Answer 30

antibiotics, low protein diet, arginine therapy, gene therapy