Biochemistry- Hemoglobins Flashcards Preview

NPLEX I > Biochemistry- Hemoglobins > Flashcards

Flashcards in Biochemistry- Hemoglobins Deck (23)
1

What substance, when bound to heme, weakens the oxygen/heme bond causing the oxygen to be released?

2,3- diphosphoglycerate

2

What can bind to hemoglobin?

O2, CO2, CO, H+, and 2,3- diphosphoglycerate

3

What are the 3 functions of hemoglobin?

oxygen transport, CO2 transport, blood buffer

4

What 2 substances are the starting material for heme synthesis?

succinyl CoA, glycine

5

What do succinyl CoA and glycine form?

delta aminolevulenic acid (and then --> heme formation)

6

What is the regulatory enzyme in heme synthesis?

Delta aminolevulenic acid synthase (ALAS)

7

The formation of porphobilinogen from Delta aminolevulenic acid is catalyzed by what enzyme?

Delta aminolevulenic dehydrogenase (ALAD)

8

What substance inhibits ALAD?

Lead

9

What mineral is incorporated into heme?

Iron

10

Where does heme synthesis take place?

mitochondria

11

Where in the body does heme synthesis take place?

bone marrow

12

Congenital deficiencies of certain enzymes in the heme synthesis are known as:

porphyrias

13

In what other substances is heme found?

Myoglobin, cytochromes

14

Where does catabolism of heme take place?

Spleen, then liver and finally intestines. may also occur in bone marrow

15

What creaks down heme during tissue damage?

macrophages

16

what is the first substance produced by heme catabolism?

biliverdin

17

Biliverdin is converted into what molecule?

bilirubin

18

Where is bilirubin conjugated?

liver

19

How is bilirubin secreted?

in bile

20

Bacteria in the gut convert some of the bilirubin into what substance?

Urobilinogen

21

What is the fate of urobilinogen?

reabsorbed, transported to the kidneys and converted into urobilin and excreted

22

What are the 2 excretory pathways for heme catabolism?

feces and urine

23

What role does H+ binding to hemoglobin have?

induces hemoglobin to unload its bound oxygen