hemoglobin and myoglobin

Question 1

blood contains what percentages or RBC?

Answer 1

40%

Question 2

blood contains what percentages or WBC?

Answer 2

1%

Question 3

blood contains what percentages or plasma?

Answer 3

59%

Question 4

Hb ____ o2 in the alveoli in the lungs and dilivers o2 to tissues throughout the body

Answer 4

binds

Question 5

Hb ____ in maintaining acid-base balancing the body by binding some CO2 produced by metabolism and releasing CO2 when HB reaches the lungs

Answer 5

assists

Question 6

both functions of hemoglobin are dependent on

Answer 6

partial pressure

Question 7

myoglobin is synthesized inside

Answer 7

muscle cells

Question 8

myoglobin stores oxygen in muscles cells for use at times of high/low metabolic demand

Answer 8

high

Question 9

structure of myoglobin

Answer 9

• single polypeptide chain - 80% alpha helical - closely-packed tertiary structure

Question 10

structure of hemoglobin

Answer 10

• four polypeptide chains 2 alpha and 2 bets - strong hydrophobic interactions between alpha 1 and beta 1 and alpha ii and beta ii

Question 11

hemoglobin can bind ____ O2 molecules because it has ____ heme molecules

Answer 11

4; 4

Question 12

heme molecules are ____ bonded to subunits of myoglobin and hemoglobin

Answer 12

covalently

Question 13

myoglobin can bind ____ O2 molecules because it has ____ heme molecules

Answer 13

1; 1

Question 14

hemoglobin subunits have strong/weak ___ interactions between heterodimers alpha 1beta 1 and alpha II and beta II

Answer 14

• weaker polar interactions

Question 15

HbA

Answer 15

alpha2 beta2; 97-98% of total Hb in adult

Question 16

HbA2

Answer 16

alpha2 delta 2 1.5-3% of total Hb in adult

Question 17

HbF

Answer 17

alpha 2 gamma 2; fetal; 1 month gestation until near brith

Question 18

Hb epsilon

Answer 18

embryonic Hb 1 week post-conception until birth

Question 19

alpha globin genes are found on ____ chromosome

Answer 19

16

Question 20

beta globin genes are found on ____ chromosome

Answer 20

11

Question 21

glycosylation of ____ is a marker for chronically elevated blood sugar

Answer 21

of alpha2beta2 (HbA)

Question 22

organ progression of Hb generation

Answer 22

yolk sac liver spleen bone marrow

Question 23

Answer 23

1. alpha
2. beta
3. delta

Question 24

deletion of the globin gene leads to

Answer 24

thalassemia

Question 25

thalassemia

Answer 25

imbalance in globin chain synthesis

Question 26

pyrrole rings

Answer 26

coordinate covalent bonds to Fe2+

Question 27

hydrophobic/hydrophilic chains from the pyrrole rings interact with the surrounding alpha beta globin chains to stabilize heme binding

Answer 27

hydrophobic

Question 28

heme belongs to the class of pigments known as

Answer 28

porphyrins

Question 29

myoglobin binding curve is sigmodial/hyperbolic indicating a single constant affinty for O2

Answer 29

hyperbolic

Question 30

hemoglobin binding curve is sigmodial/hyperbolic indicating a changing affinty for O2

Answer 30

sigmodial

Question 31

P50

Answer 31

the parital pressure where 50% of the oxygen binding sites are occupied

Question 32

hemoglobin exists in two conformational forms

Answer 32

T (taut) and R (relaxed)

Question 33

the T conformation favors the

Answer 33

deoxy form (O2 release)

Question 34

the R conformation favors the

Answer 34

oxy form (O2 binding)

Question 35

O2 is a ____ regulator of Hb O2 binding

Answer 35

positive allosteric

Question 36

2,3 di-phosphoglycerate (2,3 DPG) AND 1,3 BISPHOSPHOGLYCERATE stabilizes the T/R conformation

Answer 36

T deoxy conformatoin allowing realse of oxygen to the tissues

Question 37

levels of 2,3 DPG increase

Answer 37

chronic COPD, pregnancy, high altitude, chronic anemia, and pregnancy

Question 38

levels of 2,3 DPG INCREASE IN HYPOXIA BECAUSE

Answer 38

at lower partial pressure more oxygen will be realsed to tissues

Question 39

carbonic anhydrase

Answer 39

enzynme that catalyzes CO2 + H2O --\> carbonic acid H2CO3

Question 40

haldane effect

Answer 40

favors synthesis of CO2 and H2O

Question 41

bohr effect

Answer 41

favors O2 release, protons bind to the Hb and favor T conformation

Question 42

increas in pH favors O2

Answer 42

binding

Question 43

decrease in pH favors O2

Answer 43

release

Question 44

fetal hemoglobin has a different beta chain that has a higher/lower affinity for O2

Answer 44

higher

Question 45

HbF binds 2,3 DPG _____ becuase the cavity is not as positively charged

Answer 45

poorly

Question 46

Hb F has a higher/lower O2 binding affinity than Hb A in the mother

Answer 46

higher

Question 47

what has the highest affinity for oxygen

Answer 47

myoglobin

Question 48

over 1100 Hb variants known most are the result of ____ mutations

Answer 48

point that change a single amino acid

Question 49

the most common Hb variant associated with significant pathology in the US is

Answer 49

betaS variant

Question 50

beta S variant is caused by

Answer 50

mutation at position 6 of B globin gene which changes Glu6 to Val6

Question 51

beta S mutation can lead to

Answer 51

sickle cell anemia

Question 52

which forms more readily carboxyhemoglobin or oxyhemoglobin?

Answer 52

carboxyhemoglobin

Question 53

compounds that inhibit oxygen binding

Answer 53

cyanide (CN-) carbon monoxide (CO) nitrogen dioxide (NO2) hydrogen sulfide (h2s)

Question 54

cyanide (CN-) carbon monoxide (CO) nitrogen dioxide (NO2) hydrogen sulfide (h2s) inhibit hemoglobin by

Answer 54

competitive inhibition

Question 55

mutations that change any of the 3 aa to make the binding less hydrophobic and more hydrophilic result in

Answer 55

hereditary methemoglobinemia

Question 56

hereditary methemoglobinemia

Answer 56

characterized by cyanosis (blueish color of the skin) and brown color to blood

Question 57

cytochrome b5 reductase

Answer 57

Fe3+ --\> Fe2+

Question 58

causes of methemoglobinemia

Answer 58

- mutations in ytochrome b5 reductase - mutations in pentose phosphate pathway

Question 59

\_\_\_\_\_ normally reduces reactive oxygen species thereby preventing formation of methemoglobin

Answer 59

glutathione