Hemoglobin

Question 1

What four subunits is HbA made of?

Answer 1

two alpha subunits

two beta subunits

Question 2

What four subunits is HbA2 made of?

Answer 2

two alpha

two delta

Question 3

What four subunits is HbF composed of?

Answer 3

two alpha

two gamma

Question 4

What amino acid substitution is present in HbF? What can this new amino acid bind?

Answer 4

histidine to serine

23BPG

Question 5

What chromosome are the alpha globins located?

Answer 5

16

Question 6

What chromosome are the beta globins located?

Answer 6

11

Question 7

HS-40 corresponds to what globin gene?

Answer 7

alpha

Question 8

LCR corresponds to what globin chain?

Answer 8

beta

Question 9

What is the amino acid substitution during HbS?

Answer 9

glutamate to valine

Question 10

What drug is used to manage HbS? Why is this drug used?

Answer 10

Hydroxyurea

increases levels of HbF

Question 11

What amino acid residue is present during HbC? What is thought to happen to HbC?

Answer 11

glutamic acid to lysine

crystallization

Question 12

What amino acid substitution is present during HbS?

Answer 12

glutamate to valine

Question 13

How many genes are there for α-globin? What chromosome?

Answer 13

four

16

Question 14

In a person with severe (three gene deletion) α-thalassemia, what form of hemoglobin will form? What globin isotypes make this up?

Answer 14

Hb Barts

four gamma chains

Question 15

When fetal Hb production winds down, what form of Hb will a person with severe α-thalassemia produce? What globin chain isotypes make this up?

Answer 15

HbH

four beta chains

Question 16

Why are Hb Barts and HbH poor oxygen transporters?

Answer 16

too high of O2 affinity

Question 17

What amino acid substitution is present during HbE? Where?

Answer 17

glutamate to lysine

southeast asia

Question 18

What is the only α-thalassemia that can be caused by a point mutation? What is produced?

Answer 18

Hb constant spring

excessively long α2 chain

Question 19

What type of recombination takes places in Hb Lepore?

Answer 19

fusion of beta and delta

Question 20

At a pH of 8.6, will HbA be positively or negatively charged?

Answer 20

negatively

Question 21

What amino acid of hemoglobin can protons bind? What other amino acid will this charged histidine now bind?

Answer 21

histidine

aspartate

Question 22

What is formed when CO2 binds Hb?

Answer 22

carbamates

Question 23

At what position is the amino acid substitution in HbS? What chain?

Answer 23

position 6

beta chain

Question 24

Which hemoglobinopathy has the same position and chain error as HbS?

Answer 24

HbC

Question 25

What position in the mutation in HbE? What chain? What happens to this globin?

Answer 25

26 beta chain inefficient synthesis

Question 26

During HbLepore, what part of the mRNA contains delta globin? Beta globin?

Answer 26

delta = N-ter beta = C-ter

Question 27

What is the function of HS-40 and LCR?

Answer 27

tissue specific expression of Hb

Question 28

What do HbS homozygotes have? Heterozygotes?

Answer 28

homozygotes = disease heterozygotes = trait

Question 29

If four α-globin genes are deleted, what are the two isotypes of α-globin that can predominate?

Answer 29

Gower Portland

Question 30

What is the error during Hb Constant Spring?

Answer 30

stop codon is changed to a glutamine residue

Question 31

Does Hb Constant Spring behave like a α+ or an α0 thalassemia?

Answer 31

α+

Question 32

What are the three Hb's produced in the early embryo?

Answer 32

Gower 1, Gower 2 and Portland

Question 33

What does oxidized Fe3+ form?

Answer 33

hemichrome

Question 34

In what population is HbC confined?

Answer 34

West Africans

Question 35

What type of problems can accumulate in a patient with HbSC?

Answer 35

ocular

Question 36

Why can HbS and HbA be separated on an electrophoresis?

Answer 36

HbS is slightly more negative

Question 37

What restriction endonuclease is used for PCR HbS vs. HbA?

Answer 37

Mst II

Question 38

Other than polymerizing, what does the valine in HbS accomplish?

Answer 38

block O2 binding site on β-chain

Question 39

What is the amino acid substitution in Hb Helsinki? Where? What does this result in?

Answer 39

Lys to Met 2,3-BPG binding site increased O2 affinity

Question 40

What is the amino acid substitution in Hb kansas? What does this result in?

Answer 40

Asn to Thr decreased oxygen affinity

Question 41

What are the two hemoglobinopathies that readily form methemoglobin?

Answer 41

boston and hyde park

Question 42

What is the common error for almost all α-thalassemias? Due to what?

Answer 42

deletion homologous recombination