Biochemistry

Question 1

What are the 3 final products when heme is complexed with proteins?

Answer 1

Hemoglobin, myoglobin, and the cytochromes.

Question 2

These are hereditary or acquired conditions of defective heme synthesis that leads to the accumulation of heme precursors.

Answer 2

Porphyrias

Question 3

To start making heme, we start the recipe with 8 molecules of glycine and 8 molecules of ___________

Answer 3

Succinyl-CoA

Question 4

Succinyl CoA and glycine combine to form what acid?

Answer 4

δ-aminolevulinic acid (δ-ALA)

Question 5

Why is δ-ALA synthase important in the synthesis of heme?

Answer 5

It’s the rate limiting step

Question 6

Which vitamin does δ-ALA require to fxn?

Answer 6

B6

Question 7

So what type of anemia can result from a B6 deficiency?

Answer 7

microcytic, hypochromatic anemia

“sideroblastic anemia”

Question 8

After protoporphyrin IX is produced, which metal combines with it, catalyzed by heme synthase?

Answer 8

Fe++

Question 9

Which 2 substances inhibit δ-ALA synthase? (think negative feedback)

Answer 9

heme and glucose

Question 10

Lead poisoning inactivates δ-ALA dehydratase, which can lead to an accumulation of what substance?

Answer 10

δ-ALA

Question 11

A lack of iron or inhibition of ferrochelatase can lead to an accumulation of what heme precursor?

Answer 11

protoporphyrin IX

Question 12

What are the 2 products of hemoglobin degradation?

Answer 12

heme + globin

hurrrrrrrrrrrrrrrrrrrrrrrrr

Question 13

What is the product of heme degradation?

Answer 13

bilirubin

this is why bruises turn yellow after being purple, because bilirubin is yellow

Question 14

Bilirubin is first converted to what substance before being excreted in the bile?

Answer 14

it’s conjugated to glucuronic acid

Question 15

This is where heme is degraded to biliverdin.

Answer 15

Macrophage

Question 16

This is where albumin complexes with unconjugated bilirubin.

Answer 16

Blood

Question 17

This is where UDP-glucuronate conjugates heme into bilirubin digluconide to be excreted in the bile.

Answer 17

Liver

Question 18

This is where bacteria deconjugate bilirubin and convert it into urobilinogen.

Answer 18

Gut

Question 19

20% of this heme degredation product is absorbed into the blood and excreted in the urine, and 80% is oxidized and exreted int eh feces.

Answer 19

Urobilinogen