Hemoglobin

Question 0

What does hemoglobin do?

Answer 0

Transports O2 from the lungs to tissue

Facilitates CO2 transfer from tissue to lungs

Question 1

What is hemoglobin?

Answer 1

A highly specialized intracellular RBC protein

Question 2

Hemoglobin occupies how much of the volume of RBC?

Answer 2

33%

Question 3

How much does hemoglobin account for RBC dry weight?

Answer 3

90%

Question 4

Each cell contains how how much hemoglobin?

Answer 4

28 - 34 pg

Question 5

Most hemoglobin synthesis occurs in what?

Answer 5

Polychromatophilic normoblast

Question 6

What percentage of hemoglobin is made before the nucleus is extruded?

Answer 6

75 - 80%

Question 7

20 - 25% of hemoglobin was made by what?

Answer 7

Residual RNA & mitochondria in the reticulocyte

Question 8

Hemoglobin concentration is the result of a fine balance between what?

Answer 8

RBC production & destruction

Question 9

Hemoglobin has what type of protein?

Answer 9

Globular protein 64.4 kD

Question 10

How many hemoglobin are there per RBC?

Answer 10

250 million / RBC

Question 11

What are the components of the molecular hemoglobin structure?

Answer 11

2 alpha chains
2 beta chains
Each chain has a heme
Each heme has a tetrapyrrole ring with iron (Fe2+) in the center
Each iron/heme can bind to one O

Question 12

What are the functions of hemoglobin?

Answer 12

Transport & release oxygen to tissues with specific conditions
Removal of CO2

Question 13

What are the two conformations of hemoglobin?

Answer 13

“Relaxed”Oxyhemoglobin

“Tense”Deoxyhemoglobin

Question 14

What does relaxed oxyhemoglobin have?

Answer 14

High affinity for O2

Question 15

What does tense deoxyhemoglobin have?

Answer 15

Low affinity for O2

2,3-DPG (diphosphoglycerate)

Question 16

When hemoglobin has a high affinity for O2 what happens?

Answer 16

It binds to O2 more avidly

Does not readily release it

Question 17

When hemoglobin has a low affinity for O2 what happens?

Answer 17

Releases its O2 more readily to tissues

Question 18

What does respiratory movement mean in regards to hemoglobin?

Answer 18

It has an allosteric shape with oxygen addition & release

Question 19

How does 2,3-DPG affect oxygen affinity?

Answer 19

It’s the primary allosteric regulator of Hb

Large amounts of 2,3-DPG changes Hb from relaxed to tense

Question 20

Increased 2,3-DPG shifts O2 saturation cure to what direction?

Answer 20

Right

Question 21

What type of protein is hemoglobin?

Answer 21

Allosteric protein

Question 22

Allosteric protein means that it does what?

Answer 22

Changes shape

Question 23

What molecules affect Hb?

Answer 23

Protins (H+)
CO2
2,3-DPG

Question 24

What preferentially binds to deoxyhemoglobin?

Answer 24

2,3-DPG, CO2 H+

Question 25

When 2,3-DPG , CO2, or H+ bind to deoxyhemoglobin what happens?

Answer 25

Forms salt bridges within & between chains | Stabilizes T conformation of Hb

Question 26

2,3-DPG binds to Hb in what ratio?

Answer 26

1:1

Question 27

Where does 2,3-DPG bind to on hemoglobin?

Answer 27

In the central cavity of the Hb tetramer between the beta-globin chains

Question 28

When 2,3-DPG binds to Hb what happens?

Answer 28

Stabilizes the quarternary structure of deoxyhemoglobin

Question 29

What type of interaction is O2 binding to Hb?

Answer 29

Heme-heme interaction

Question 30

What is the ratio that O2 binds to H2?

Answer 30

4:1 | One O2 binds to each heme group of the tetramer

Question 31

Does the T conformation of deoxyhemoglobin have low or high O2 affinity?

Answer 31

Low

Question 32

When O2 is loaded onto the Hb molecule what happens?

Answer 32

Salt bridges are broken causing the molecule to go from tense to relaxed state when the third O2 is loaded Pulls the beta-chains together & expels 2,3-DPG

Question 33

When O2 is released by Hb into the tissues what happens?

Answer 33

Heme pockets narrow Restrict entry of O2 Space between the beta-chains widen 2,3-DPG binds again in the central cavity

Question 34

Tense hemoglobin is called what?

Answer 34

Deoxyhemoglobin

Question 35

O2 affinity is usually expressed as what?

Answer 35

PO2 at which 50% of the Hb is saturated with O2 (P50) | P50 in humans ˜26-28 torr (mmHg)

Question 36

Bohr effect

Answer 36

Physiological phenomenon stating that hemoglobin's oxygen binding affinity is inversely related both to acidity & the concentration of carbon dioxide Increase of CO2 decreases pH -> Hb releases O2 Decrease of CO2 increases pH -> Hb picks up O2

Question 37

Increased acid shifts the oxygen dissociation curve which way?

Answer 37

Right

Question 38

Decreased acid shifts oxygen dissociation curve which way?

Answer 38

Left

Question 39

What values (high/low) of pH, DPG, temp, & P50 for a right shifted oxygen curve?

Answer 39

Low pH High DPG High temp High P50

Question 40

What is P50?

Answer 40

50% of Hb is saturated with O2

Question 41

What values (high/low) of Hb, pH, DPG, temp, & P50 are a left shifted oxygen curve?

Answer 41

``` High Hb High pH Low DPG Low temp Low P50 ```

Question 42

What are the types of abnormal hemoglobin?

Answer 42

Carboxyhemoglobin Methemoglobin Sulfhemoglobin

Question 43

Carboxyhemoglobin is formed when?

Answer 43

Hb is exposed to CO (carbon monoxide)

Question 44

Carboxyhemoglobin results in a shift in what direction?

Answer 44

Left

Question 45

Carboxyhemoglobin results in high/low affinity & a high/ low release of O2 by what?

Answer 45

High affinity Low release of O2 Remaining normal to Hb molecules

Question 46

What color is the blood & skin due to carboxyhemoglobin?

Answer 46

Cherry red

Question 47

What causes methemoglobin?

Answer 47

Hb with iron in the ferric (Fe+++) state

Question 48

Hb affinity for CO is 200 times higher than for O2 is?

Answer 48

Carboxyhemoglobin

Question 49

In methemoglobin Hb can or cannot bind O2?

Answer 49

Cannot

Question 50

In methemoglobin Hb has a high/low affinity of remaining normal Hb & increases/decreases O2 carrying capacity of the blood?

Answer 50

High afffinity | Decreases O2 carrying capacity

Question 51

Methemoglobin can be what three types?

Answer 51

Congenital Hereditary Acquired

Question 52

The blood sample can be what in color?

Answer 52

Chocolate brown

Question 53

Sulfhemoglobin is caused when?

Answer 53

A sulfur atom binds to periphery of porphyrin ring of the heme group of Hb

Question 54

Characteristics of sulfhemoglobin are?

Answer 54

Stable compound RBC carries it until the cell is removed from circulation Can combine with CO to form carboxysulfhemoglobin

Question 55

Sulfhemoglobin is elevated in what conditions?

Answer 55

Severe constipation | Bacteremia with Clostridium

Question 56

Sulfhemoglobin is associated with what?

Answer 56

Occupational exposure to sulfur compounds Environmental exposure to polluted air Exposure to certain drugs

Question 57

May build up with chronic constipation & is irreversible?

Answer 57

Sulfhemoglobin

Question 58

Patient blood has chocolate brown color?

Answer 58

Methemoglobin

Question 59

200 times the affinity for hemoglobin than oxygen, easily fatal?

Answer 59

Carboxyhemoglobin

Question 60

What will NOT shift the oxygen dissociation to the right?

Answer 60

Increased pH

Question 61

What are the steps in hemoglobin composition synthesis?

Answer 61

4 globin chains - protein synthesis Each globin has 1 heme - heme synthesis Each heme has 1 iron - iron transport/storage

Question 62

What is heme?

Answer 62

An iron containing non-protein portion of the hemoglobin molecule

Question 63

What is the structure of heme?

Answer 63

Ferro-protoporphyrin, a cyclical compound with 4 Pyrrhole rings* held together by nitrogen bonds holding an atom of iron in the center

Question 64

Each heme contains one atom of what?

Answer 64

Ferrous iron

Question 65

Ferrous iron has a bond that does what?

Answer 65

Reversibly binds oxygen

Question 66

Hemoglobin biosynthesis occurs where?

Answer 66

Mitochondria

Question 67

What is COPRO?

Answer 67

Coproporphyringen

Question 68

What is PROTO?

Answer 68

Protoporhpyrin

Question 69

What is the sequence of heme biosynthesis (6 parts)?

Answer 69

``` ALA PBG - Porphobilinogen URO - Uroporphyrinogen COPRO - Coproporphyrinogen Protoporphyrinogen/PROTO - Protoporphyrin IX ```

Question 70

Assembly of hemoglobin occurs where?

Answer 70

Mitochondria

Question 71

What hemoglobins are in adults?

Answer 71

HbA - a2b2 | Alpha 2 Beta 2

Question 72

What hemoglobin are in newborns?

Answer 72

a2g2 Fetus - HbF | Alpha 2 Gamma 2

Question 73

What hemoglobins are found in small amounts in adults?

Answer 73

a2d2 - HbA2 | Alpha 2 Delta 2

Question 74

What hemoglobins are found in embryos?

Answer 74

a2e2 | Alpha 2 Epsilon 2

Question 75

Adult hemoglobin consists of 2 alpha and 2 ____ globins?

Answer 75

Beta

Question 76

Fetal hemoglobin consists of 2 alpha and 2 _____ globins?

Answer 76

Gamma

Question 77

What hemoglobin starts in the fetus?

Answer 77

Beta

Question 78

What hemoglobin is in the fetus?

Answer 78

Gamma

Question 79

What is the sequence of hemoglobin from embryo to birth?

Answer 79

Epsilon Gamma Beta

Question 80

What type of hemoglobin is in the embryonic stage?

Answer 80

Epsilon

Question 81

What hemoglobin is in the fetal stage?

Answer 81

Gamma

Question 82

What hemoglobin is present throughout a persons life?

Answer 82

Alpha

Question 83

What hemoglobin starts high before birth but drops after birth?

Answer 83

Gamma

Question 84

What hemoglobin starts low before birth but then goes up after birth?

Answer 84

Beta

Question 85

What is the correct order of heme synthesis?

Answer 85

``` Succinyl CoA + glycine Delta ALA Porphobilinogen Uroporphyrinogen Coprophorphyrinogen Protophorphyrinogen Heme ```

Question 86

Tense hemoglobin has what?

Answer 86

2,3-DPG

Question 87

A patient with pH of 7.035 will have what effect on hemoglobin saturation?

Answer 87

Shift to the right

Question 88

What globin chain is turned on during embryonic development and stays on?

Answer 88

Alpha