hemoglobin

Question 1

what step is the regulatory step in hemoglobin synthesis

Answer 1

the ALAS step to product delta aminolevulinate (1st step in synthesis pathway

Question 2

at what two sites can lead inhibition occur?

Answer 2

2nd step: ALA–> porphobilinogen. will cause build up of ALA in lead poisoning present
last step: protophyrin IX –>heme. lead inhibits enzyme needed: ferrochelatase. CoPro III will be built up in urine

Question 3

how many succinul CoA and glycines are needed to make 1 heme

Answer 3

8 of each

Question 4

what are 4 mechanisms of heme synthesis inhibition

Answer 4

1. repression of mRNA synthesis (inhibiting transcription)
2. inhibit translation of the ALA synthase mRNA
3. inhibit import of the ALA synthase protein into mitochondria
4. direct inhibition of ALA enzyme

Question 5

what is heme needed for in the liver

Answer 5

for cytochrome p450 -needed for alcohol detoxification

Question 6

cause of congenital erythropoietic porphyria (CEP)

Answer 6

build up of urophyrinogen I and CoPro I
caused by deficiency of uroporphyrinogen III co synthase
werewolf syndrome

Question 7

cause of erythropoietic protophyria

Answer 7

deficiency of ferrochelatase enzyme

Question 8

cause acute intermittent porphyria (AIP)

Answer 8

affects liver
usually patients are asymptomatic until it is brought on by something else (alcohol, estrogen..)
deficiency of PBG deaminase
build up of PPG and deposit it in your urine making it red color
also build up of ALA
causes neurological rages

Question 9

porphyria cutanea tarda

Answer 9

affects liver
deficiency of uroporphyrinogen decarboxylase
linked with hep C
link with people drinking and on birth control

Question 10

3 steps and location of heme degradation

Answer 10

1. break ring-spleen
2. reduce broken ring-spleen
3. conjugate sugars to make it water soluble-liver

Question 11

cause of crigler najjar syndrome

Answer 11

deficiency in UDP glucuronul transferase (enzyme needed for 3rd step) and results in severe jaundice

Question 12

cause of neonatal jaundice

Answer 12

temporary inability to produce sufficient amounts of UDP glucuronul transferase by an infant

Question 13

severe result of neonatal jaundice

Answer 13

kernicterus

Question 14

name of hemoglobin when the iron has been oxidized

Answer 14

methemoglobin dimer

Question 15

what does intestinal bacteria do to conjugated bilirubin?

Answer 15

convert it into urobilinogens and other products

Question 16

what gives urine/feces its color?

Answer 16

urobilin (made from conversion of urobilinogen)

Question 17

characteristic of prehaptatic jaundice

Answer 17

unconjugated bilirubin in the blood

Question 18

characteristic of hepatic jaundince

Answer 18

serum mixture of both conjugated and unconjugated buildup

you will also see increased liver function ezymes

Question 19

characteristic of posthepatic jaundice

Answer 19

buildup of conjugated bilirubin

Question 20

how is iron stored?

Answer 20

as ferritin and hemosiderin

in liver, bone marrow, skeletal muscles and spleen

Question 21

Which enzymes use heme as an electron carrier?

Answer 21

1. hemoglobin
2. myoglobin
3. cytochrome C
4. catalase
5. cytochrome P450
6. ubiquinol cyt c reductase
7. cyt. c oxidase
   8 tryptophan pyrrolase
8. neutrophil NADPH oxidase
9. NO synthase
10. cystathionase

Question 22

What is the order of the functional groups in a protophoryrin?

Answer 22

M v m v m p p m

Question 23

What is a pyrrole?

Answer 23

A four carbon ring with a nitrogen

Question 24

What is a porphyrin?

Answer 24

an oxidized tetrapyrrole

Question 25

What is a porphyrinogen?

Answer 25

a reduced tetrapyrrole

Question 26

Which diseases are autosomal dominant?

Answer 26

1. Protoporphyria
2. Acute intermittent hepatic prophyria
3. porphyria cutanea tarda

Question 27

Which diseases are autosomal recessive?

Answer 27

Congenital erythropoietic porphyria

Question 28

What is different about the hepatic porphyrias and the erythropoietic porphyrias?

Answer 28

The hepatic conditions are usually asymptomatic until environmental factors are introduced such as alcohol. The erythropoietic conditions are chronic

Question 29

What is the role of haptoglobin?

Answer 29

Binds methemoglobin dimers

Question 30

What is the role of hemepexin?

Answer 30

Binds free heme

Question 31

What is the role of transferrin?

Answer 31

Binds free iron

Question 32

How is bilirubin transported to the liver?

Answer 32

As a complex with albumin

Question 33

What form of the products of heme breakdown, is a major antioxidant?

Answer 33

Bilirubin

Question 34

What is the other role of transferrin, besides storing iron?

Answer 34

It acts as an antimicrobial because some bacteria are siderophores