Biochemistry

Question 1

what enzyme releases Fe2+ from heme

Answer 1

heme oxygenase

Question 2

what is non-heme taken up by

Answer 2

dmt-1

Question 3

what is the role of ceruloplasmin/hephaestin in Fe2+ metabolism

Answer 3

oxidize ferroportin that transports Fe2+ out of enterocytes

Question 4

transcription of what enzyme is suppressed in iron deficiency anemia

Answer 4

hepcidin

Question 5

what is the role of hepcidin

Answer 5

regulates ferroportin

Question 6

what are the steps of iron metabolism

Answer 6

absorption and storage
recycling
uptake

Question 7

where does heme synthesis occur

Answer 7

mitochondria then cytosol then mitochondria

Question 8

describe heme synthesis

Answer 8

succinyl co-A and glycine form delta ALA with delta ALA synthase
delta ALA with delta ALA dehydratase gives porphobilinogen
porphobilinogen gives protoporphyrin
ferrochelatase adds Fe2+ to protoporphyrin to give heme

Question 9

lead poisoning inhibits what enzymes in heme synthesis pathway

Answer 9

delta ALA dehydratase and ferrochelatase

Question 10

what inhibits ALAS1 and ALAS2

Answer 10

ALAS1 inhibited by heme/hemin
ALAS2 inhibited by iron

Question 11

what happens to the end products after heme degradation

Answer 11

biliverdin turns into bilirubin
iron is reuptaken
CO is excreted by lung

Question 12

what happens to bilirubin upon degradation

Answer 12

degraded by bilirubin UGT
urobilinogen gives urine yellow color
stercobilin gives feces brown color

Question 13

UROD def

Answer 13

porphyria cutanea tarda

Question 14

symptoms of porphyria cutanea tarda

Answer 14

blistering skin lesions
elevated liver panel
tea colored urine
iron overload (no anemia)
photosensitivity

Question 15

diagnosis and treatment of porphyria cutanea tarda

Answer 15

diagnosis: elevated uroporphyrin in urine or plasma
treatment: phlebotomy, malarial drugs

Question 16

PBGD def

Answer 16

acute intermittent porphyria

Question 17

what triggers acute intermittent porphyria

Answer 17

medication
alcohol
smoking
low glucose

Question 18

symptoms of acute intermittent porphyria

Answer 18

port wine urine
psychological disturbances
polyneuropathy
precipitated by drugs
abdominal pain

Question 19

treatment of acute intermittent porphyria

Answer 19

glucose
hemin

Question 20

ferrochelatase def

Answer 20

erythropoietic protoporphyria (EPP)

Question 21

what are the forms of hemoglobin

Answer 21

taut and relaxed form

Question 22

what does it mean when hemoglobin is in the taut form

Answer 22

low o2 affinity = releases o2 in tissues

Question 23

what does it mean when hemoglobin is in the relaxed form

Answer 23

high o2 affinity = holds on to o2 taken from lungs

Question 24

how does pH and CO2 affect oxygen affinity

Answer 24

high pH, low CO2 = high O2 affinity
low pH, high CO2= low O2 affinity

Question 25

how does 2,3 BPG affect oxygen affinity

Answer 25

it reduces oxygen affinity

Question 26

in chronic anemia, how would you describe levels of 2,3BPG

Answer 26

elevated

Question 27

how do we treat CO poisoning

Answer 27

hyperbaric oxygen therapy (100% O2 at high pressure)

Question 28

CO poisoning symptoms

Answer 28

malaise headache cherry red lips nausea dizziness

Question 29

when does HbA start to replace HbF

Answer 29

eighth month of pregnancy in bone marrow

Question 30

who has higher oxygen affinity HbA or HbF? why?

Answer 30

HbF has higher oxygen affinity because it binds weakly to 2,3 BPG unlike HbA

Question 31

how is HbA1C clinically useful

Answer 31

elevated in diabetic patients (diagnostic and monitoring)

Question 32

what is the mutation in sickle cell anemia

Answer 32

point mutation (substitution) in beta globin gene (glutamate replaced by valine)

Question 33

symptoms of sickle cell anemia

Answer 33

pain crises hemolytic anemia BM hyperplasia jaundice

Question 34

what increases sickling

Answer 34

decreased pO2 increased pCO2 decreased pH dehydration increase 2,3BPG

Question 35

treatment of sickle cell anemia

Answer 35

blood transfusion (benefits outweigh risks) hydroxyurea/hydroxycarbamide stem cell transplant

Question 36

what disease is characterized by having glutamate replaced by lysine

Answer 36

hemoglobin C disease

Question 37

chocolate cyanosis is characteristic of what disease

Answer 37

methemoglobinemia

Question 38

what are the levels of alpha thalassemia

Answer 38

1: silent = asymptomatic 2: trait 3: hemoglobin H (beta4) = hemolytic anemia 4: hemoglobin bart (gamma4) = hydrops fetalis (fetal death)

Question 39

beta thalassemia minor characteristics

Answer 39

elevated HbA2 asymptomatic mild anemia

Question 40

beta thalassemia major characteristics

Answer 40

anemia elevated HbF splenomegaly

Question 41

cause of sideroblastic anemia

Answer 41

mutation in ALAS2

Question 42

which enzyme is expected to be inhibited in a patient with sideroblastic anemia

Answer 42

delta ALA synthase