Hemoglobin & Myoglobin

Question 1

_____ is a complex of protoporphyrin IX and ferrous ion (Fe2+)

Answer 1

Heme

Question 2

What does heme do in hemoglobin and myoglobin?

Answer 2

it serves to reversibly bind oxygen

Question 3

Where is Myoglobin present?

Answer 3

Heart and skeletal muscle

Question 4

What is the function of myoglobin?

Answer 4

reservoir of oxygen in red muscle fibers

Question 5

When is the oxygen that is stored in myoglobin released?

Answer 5

During oxygen deprivation

Question 6

Does myoglobin have a high or low molecular weight?

Answer 6

Low ~17,000

Question 7

Where is Hemoglobin present?

Answer 7

in RBCs

Question 8

What is the function of Hemoglobin?

Answer 8

it reversibly carries oxygen from lungs to peripheral tissues, and H+ and some CO2 from peripheral tissues to the lungs.

Question 9

HbA has what?

Answer 9

2 alpha, 2 beta

Question 10

HbF has what?

Answer 10

2 alpha, 2 gamma

Question 11

HbA2 has what?

Answer 11

2 alpha, 2 delta

Question 12

How long does embryonic hemoglobin persist?

Answer 12

from 15 days after fertilization until 6 weeks of embryonic life

Question 13

When does HbF predominate?

Answer 13

from 6 weeks of fetal life; gradually falls from 30 weeks of prenatal life. At birth and up until 4-5 weeks of post natal life, HbF is the predominate type.

Question 14

When completely saturated, how many oxygens do myoglobin and hemoglobin bind?

Answer 14

myoglobin binds one O2 and hemoglobin binds 4

Question 15

In the absence of oxygen (T form), the interaction between (αβ)1- (αβ)2 is ______

Answer 15

tight

Question 16

In the presence of oxygen (R form), the interaction between (αβ)1- (αβ)2 is ______

Answer 16

less tight

Question 17

______ is the degree of saturation measured at different partial pressures of oxygen

Answer 17

Oxygen dissociation curve

Question 18

2,3-BPG ______ the oxygen affinity of hemoglobin

Answer 18

decreases

Question 19

What is 2,3-BPG’s effect on deoxyhemoglobin and hemoglobin?

Answer 19

it stabilizes deoxyhemoglobin and helps to release O2 from hemoglobin.

Question 20

The levels of 2,3-BPG _____ in response to chronic hypoxia and helps to release O2 from hemoglobin

Answer 20

increase

Question 21

Factors that cause a right shift (reduced affinity) to the oxygen-hemoglobin dissociation curve

Answer 21

• increase in 2,3-BPG
• increase in PCO2
• decrease in pH

Question 22

Factors that cause a left shift (increased affinity) to the oxygen-hemoglobin dissociation curve

Answer 22

• decreased 2,3-BPG
• decrease in PCO2
• increased pH
• presence of CO

Question 23

____ glucose levels in uncontrolled type 2 DM will increase HbA1c

Answer 23

Higher

Question 24

What is the most abundant form of glycosylated hemoglobin?

Answer 24

HbA1c

Question 25

What is used to monitor the long term control of blood glucose in DM?

Answer 25

HbA1c

Question 26

What causes the release of O2 from hemoglobin?

Answer 26

low tissue pH and high PCO2

Question 27

How does CO bind to the iron of hemoglobin?

Answer 27

covalently, but reversibly

Question 28

Where is embryonic hemoglobin produced?

Answer 28

in the yolk sac

Question 29

Where are the major sites of fetal erythropoiesis?

Answer 29

liver and some spleen

Question 30

In the last few weeks before birth, what is the site of erythrocyte formation?

Answer 30

bone marrow

Question 31

Which histidine, proximal or distal, directly interacts with Fe2+ of heme?

Answer 31

His F8(proximal)

Question 32

Which histidine, proximal or distal, does not directly interact with Fe2+ of heme, but helps to stabilize the binding of oxygen to the ferrous ion?

Answer 32

His E7(distal)

Question 33

10% of total CO2 produced in peripheral tissue is carried in the form of what?

Answer 33

carbaminohemoglobin

Question 34

90% of total CO2 produced in peripheral tissue is carried in the form of what?

Answer 34

bicarbonate