Dai 3

Question 0

What cofactor is required for methylmalonyl –> succinyl coA

Answer 0

B12.

Question 1

In the propionyl coA to succinyl coA pathway, what cofactor is required from propionyl to methylmalonyl coA

Answer 1

Biotin

Question 2

What else requires B12?

Answer 2

homocysteine–>methionine. also needs THF cofactor

Question 3

What is MMA methylmalonyl aciduria?

Answer 3

deficiency in methylmalonyl mutase. methylmalonyl coA increases, inhibits malonyl coA necessary for FA synthesis and myelination .

Question 4

What carries CO2?

Answer 4

biotin

Question 5

What carries CH3?

Answer 5

THF, SAM, B12

Question 6

What carries methenyl, formyl, methylene?

Answer 6

THF

Question 7

What is the methyl folate trap?

Answer 7

prevents methyl group deficiency when dietary methionine is low. methyl THF cant convert to other 1 C THF carriers.

Question 8

folate to dihydrofolate to tetrahydrofolate. what enzyme

Answer 8

dihydrofolate reductase. during dihydrofolate deficiency, treat with formyl THF to bypass need for enzyme.

Question 9

Why does alcoholism lead to thf deficiency.

Answer 9

alcoholism, causes impaired absorption.

Question 10

How can you measure THF amount

Answer 10

direct test or figlu test (histidine-akg, uses thf as cofactor)

Question 11

What processes are affected if THF is deficient?

Answer 11

defective purine pyr synthesis
homocys to met
glycine cleavage

Question 12

What is required for transport and absorption of B12.

Answer 12

IF intrinsic factor.

Question 13

What is pernicious anemia?

Answer 13

deficiency of IF.

Question 14

Vitamin b12 is involved in two reactions in the body. which reactions.

Answer 14

homocysteine to methionine.
methylmalonyl coa to succinyl coa
regenerate THF.

Question 15

Without ____, the methyl in methyl THF would be trapped in methylTHF form.

Answer 15

B12.

Question 16

T or F. Heme is made out of porphyrin ring, side chains and fe2+.

Answer 16

True.

Question 17

T or F. An important step in heme formation is making the correct asymmetric porphyrin.

Answer 17

True.

Question 18

8 ______+8________+Fe2+ –> Heme

Answer 18

glycine, succinyl coa

Question 19

What enzyme catalyzes the committed and rate limiting step in heme synthesis? What is this enzyme inhibited by.

Answer 19

ALA synthetase. inhibited by end products (heme).

Question 20

Defects early in heme synthesis leads to ________ symptoms. defects later cause __________ symptoms.

Answer 20

neuropsychiatric,

cutaneous.

Question 21

What is acute intermittent porphyria?

Answer 21

deficiency in PBG deaminase. Accumulation of PBG and ALA, both which are toxic. Characterized by “attacks” of paranoia, abdominal pain, anxiety. can be precipitated by drugs, infections, fasting, stress. Treatment by glucose and heme (glucose inhibits heme synthesis somehow)

Question 22

What is porphyria cutaneous tarda?

Answer 22

defect in uroporphoryinogen decarboxylase. photosensitivity, bullae, pigmentation.

Question 23

How can you treat PCT?

Answer 23

1. avoid risk factors like etoh
2. avoid sunc
3. chloroquine can remove porphyrins for excretion
4. beta carotene (free radical scavenger)

Question 24

During heme degradation, heme is taken up by macrophages and is converted to ________ and ________.

Answer 24

bilverdin (soluble) | bilirubin (insoluble)

Question 25

Bilirubin travels through blood while complexed with _____.

Answer 25

albumin.

Question 26

Bilirubin is ____ taken up by liver cells.

Answer 26

Actively

Question 27

Bilirubin is conjugated with 2 ______, making it more _______.

Answer 27

glucuronic acids. | soluble.

Question 28

Conjugated bilirubin is secreted by the liver into _____.

Answer 28

bile

Question 29

T or F. bacteria in intestine unconjugate bilirubin diglucuronide.

Answer 29

True.

Question 30

Bilirubin is oxidized to ______ in the intestine.

Answer 30

urobilinogen.

Question 31

T or F. Urobilinogen --> stercobilin or urobilin.

Answer 31

True.

Question 32

What is jaundice?

Answer 32

yellowing eyes/skin due to bilirubin deposition. due to increased bilirubin product or decreased excretion.

Question 33

What causes increased bilirubin or decreased excretion?

Answer 33

``` excess hemolysis liver dmg (decreased uptake, conjugation, secretion) bile duct obstruction ```

Question 34

Why is unconjugated bilirubin in blood dangerous?

Answer 34

should be binding albumin. but when albumin already taken, it binds lipids, impairs membranes, especially nervous system.

Question 35

why does physiological neonatal jaundice occur? what is treatment?

Answer 35

liver not developed, low bilirubin glucuronyltransferase. treate with fluorescent light to make bilirubin more soluble isomer.