01 LEC: Erythrocyte metabolism & membrane structure

Question 1

Glucose enters the RBC by facilitated diffusion via the transmembrane protein ___

Answer 1

Glut-1

Question 2

The ___ is an anaerobic pathway that generates ATP

Answer 2

Embden Meyerhof Pathway

Question 3

The enzyme deficiency present for defective Embden Meyerhof Pathway

Answer 3

Pyruvate kinase deficiency

Question 4

The hexose monophosphate shunt is also called

Answer 4

Pentose phosphate shunt

Question 5

The hexose monophosphate shunt provides ___ and ___

Answer 5

reduced glutathione and NADPH

Question 6

Enzyme deficiency for defective hexose monophosphate shunt

Answer 6

glucose-6-phosphate dehydrogenase deficiency

Question 7

G6PD deficiency causes ___ ___ anemia

Answer 7

episodic hemolytic

Question 8

In G6PD, the denatured hgb produces ___

Answer 8

Heinz bodies

Question 9

Where can we see presence of bite cells/pitted cells?

Answer 9

G6PD deficiency

Question 10

T/F: bite cells can be seen using wright stain

Answer 10

T

Question 11

RBC components that can be seen through supravital staining

Answer 11

Reticulocyte
Heinz bodies
Hemoglobin H

Question 12

The methemoglobin reductase pathway is also called ___

Answer 12

cytochrome b5 reductase

Question 13

The methemoglobin reductase pathway is able to ___ ___ once it forms

Answer 13

Reduce methemoglobin

Question 14

T/F: NADPH is more efficient in reducing methemoglobin than cytochrome b5

Answer 14

F

Question 15

This pathway generates 2,3-bisphosphoglycerate

Answer 15

Rapoport-Luebering pathway

Question 16

Importance of 2,3-DPG/BPG in the erythrocyte metabolism

Answer 16

Expels out O2 from the hemoglobin

Question 17

The binding of 2,3-DPG/BPG shifts the hemoglobin-oxygen dissociation curve to the ___, which enhances delivery of oxygen to the tissues

Answer 17

right

Question 18

RBC membrane components

Answer 18

CHO 10%
Protein 50%
Lipid 40%

Question 19

RBC membrane phospholipids are ___ distributed

Answer 19

asymmetirically

Question 20

___ and ___ predominate in the outer layer of RBC membrane

Answer 20

phosphotidylcholine
sphingomyelin

Question 21

___ and ___ predominate in the inner layer of RBC membrane

Answer 21

phosphatidylserine
phosphatidylethanolamine

Question 22

This is described as regularly spaced projections present in a cell

Answer 22

echinocyte/burr cell

Question 23

This is described as large, irregular projections present in a cell

Answer 23

acanthocytosis/spur cell

Question 24

___ and ___ are associated with abnormalities in the concentration or distribution of membrane cholesterol and phospholipids

Answer 24

acanthocytosis and target cells

Question 25

transmembrane and cytoskeletal proteins make up ___ of the half of the RBC membrane structure by mass

Answer 25

52%

Question 26

This serve many functions, including transport sites, adhesion sites, and signaling receptors

Answer 26

transmembrane proteins

Question 27

Identify the transmembrane protein: water transporter, colton antigen

Answer 27

aquaporin 1 (AQP1)

Question 28

Identify the transmembrane protein: anion transporter, location of ABH antigens

Answer 28

Band 3 (SLC4A1)

Question 29

Identify the transmembrane protein: G protein-coupled receptor, chemokine receptor, Duffy antigens, receptor for malarial parasites

Answer 29

Duffy (FY, DARC, ACKR1)

Question 30

Identify the transmembrane protein: Glucose transporter, location of ABH blood group antigens

Answer 30

Glut-1 (SLC2A1)

Question 31

Identify the transmembrane protein: Sialic acid transporter, location of MN blood group antigens

Answer 31

Glycophorin A (GYPA)

Question 32

Identify the transmembrane protein: Sialic acid transporter, location of Ss blood group antigens

Answer 32

Glycophorin B (GYPB)

Question 33

Identify the transmembrane protein: Sialic acid transporter, location of Gerbich system antigens

Answer 33

Glycophorin C (GYPC)

Question 34

Identify the transmembrane protein: Zn binding endopeptidase

Answer 34

Kell (KEL)

Question 35

Identify the transmembrane protein: Urea transporter

Answer 35

Kidd (SLC14A1)

Question 36

Identify the transmembrane protein: D and CcEe antigens; stabilizes band 3 and Rh macrocomplexes

Answer 36

Rh (RHCE, RHD)

Question 37

Located in membrane macromolecular complexes that serve as transporters, structural components, enzymes, receptors, and adhesion molecules

Answer 37

Blood group antigens

Question 38

___ and ___ support the majority of ABH system

Answer 38

Band 3 & Glut-1

Question 39

Glycophorins C & D carry the ___

Answer 39

Gerbich system antigens

Question 40

Loss of the RhAG glycoprotein (Rh-null) prevents expression of both the D and CcEe antigens and is associated with RBC morphologic abnormalities such as ___

Answer 40

stomatocytosis

Question 41

A few copies of the ___ ___ reside in the outer, plasma-side layer of the membrane, which serves as a base on which a glycan core of sugar molecules is synthesized

Answer 41

phospholipid phosphatidylinositol (PI)

Question 42

PI serves as a base for a glycan core to synthesize ___

Answer 42

glycosylphosphatidylinositol (GPI) anchor

Question 43

They protect the RBC membrane from lysis by complement

Answer 43

GPI anchored proteins

Question 44

The GPI anchored proteins include:

Answer 44

Decay-accelerating factor (CD55) Membrane Inhibitor of Reactive Lysis (MIRL or CD59)

Question 45

An acquired mutation of PIGA genes affect the cells and make them susceptible to ___ ___

Answer 45

complement-mediated hemolysis

Question 46

The principal cytoskeletal proteins are the filamentous ___ and ___

Answer 46

a-spectrin and b-spectrin

Question 47

They arise from defects in spectrin or proteins forming the ankyrin complex that provide vertical support for the membrane

Answer 47

hereditary spherocytsosis

Question 48

They are due to defects in cytoskeletal proteins that provide horizontal support for the membrane

Answer 48

hereditary elliptocytosis

Question 49

Identify the cytoskeletal protein: filamentous antiparallel heterodimer, primary cytoskeletal proteins

Answer 49

a-spectrin b-spectrin

Question 50

Identify the cytoskeletal protein: Anchors band 3, protein 4.2, and other proteins

Answer 50

Ankyrin

Question 51

Identify the cytoskeletal protein: Anchors the actin junctional complex to spectrin tetramers, RBC cytoskeleton shape

Answer 51

Protein 4.1

Question 52

Identify the cytoskeletal protein: Part of ankyrin complex, ATP binding protein

Answer 52

Protein 4.2

Question 53

Heme is composed of ___ and ___

Answer 53

Protoporphyrin IX and Fe2+

Question 54

Heme synthesis begins in the ___ with the formation of ___

Answer 54

mitochondria ALA

Question 55

___ portion gives RBC their characteristic red color

Answer 55

heme

Question 56

Chromosome __ codes for Alpha and Zeta

Answer 56

16 (short arm)

Question 57

Chromosome __ codes for Beta, Gamma, Delta, and Epsilon

Answer 57

11 (short arm)

Question 58

The primary hemoglobin until 6 months of age

Answer 58

HgbF

Question 59

This factor binds in the B-gene promoter region

Answer 59

Kruppel-like factor 1 (KLF-1)

Question 60

T/F: during oxygenation, each one of the four heme iron atoms in a hemoglobin molecule irreversibly bind one O2 molecule

Answer 60

F (reversible)

Question 61

Approximately ___ of oxygen is bound by each gram of hemoglobin

Answer 61

1.34 mL

Question 62

Normally, a PO2 of approximately ___ results in 50% O2 saturation

Answer 62

27 mmHg

Question 63

A shift in the curve because of a change in pH

Answer 63

Bohr effect

Question 64

During __ state, there is low affinity to oxygen and it is less likely to bind to O2 molecules

Answer 64

tensed (right shift)

Question 65

During __ state, the blood is in deoxygenated form

Answer 65

tensed (right shift)

Question 66

The __ state is stabilized by a network of salt bridges and hydrogen bonds between subunits

Answer 66

tensed (right shift)

Question 67

The tensed state is more stable in condition of __ pH and __ conc of 2,3-DPG

Answer 67

low, high

Question 68

During __ state, hemoglobin has a higher affinity for oxygen

Answer 68

relaxed (left shit)

Question 69

During __ state, the hemoglobin is typically in its oxygenated form

Answer 69

relaxed (left shift)

Question 70

During relaxed state, binding of O2 disrupts the ___ and ___ that stabilized the t state

Answer 70

salt bridges hydrogen bonds

Question 71

This is formed by reversible oxidation of heme iron to the ferric state

Answer 71

methemoglobin

Question 72

Occurs after exposure to exogenous oxidants such as nitrites, primaquine, dapsone, benzocaine

Answer 72

Acquired/toxic methemoglobin

Question 73

30-50% methemoglobin, structurally abnormal polypeptide chain that favors the oxidized ferric form of iron and prevent its reduction

Answer 73

M hemoglobin/ HbM

Question 74

Levels of methemoglobin and its interpretation

Answer 74

<25% asymptomatic >30% cyanosis, hypoxia (needs IV methylene blue) >50% coma and death

Question 75

Methemoglobin causes ___ discoloration of blood

Answer 75

chocolate brown

Question 76

Methemoglobin is detected at ___ nm spectral absorption

Answer 76

630 nm

Question 77

The treatment for methemoglobin is ___

Answer 77

methylene blue

Question 78

Irreversible oxidation of hgb by materials containing sulfur or exposure to sulfur chemicals

Answer 78

sulfhemoglobin

Question 79

Addition of sulfur atom to pyrrole ring results to ___ pigment

Answer 79

greenish

Question 80

Sulfhemoglobin is also reported in px with severe constipation in cases of bacteremia due to ___

Answer 80

C. perfringens

Question 81

T/F: Sulfhemoglobin is reversible and can be converted back to adult hemoglobin

Answer 81

F (persist for the life of the cell :(()

Question 82

Sulfhemoglobin causes ___ discoloration of blood

Answer 82

mauve lavender

Question 83

Methemoglobin is detected at ___ nm spectral absorption

Answer 83

630

Question 84

Cyanmethemoglobin is detected at ___ nm spectral absorption

Answer 84

540

Question 85

Cyanmethemoglobin measures all forms of hgb except ___

Answer 85

sulfhemoglobin

Question 86

Combination of CO with heme iron

Answer 86

Carboxyhemoglobin (COHb)

Question 87

In COHb, the affinity of CO is ___x that of oxygen

Answer 87

240 (200)

Question 88

__ has been termed as the silent killer, because it is an odorless and colorless gas, and victims may quickly become hypoxic

Answer 88

CO

Question 89

Diagnosis of CO poisoning is made if the COHb levels is ___ in nonsmokers and ___ in smokers

Answer 89

3% 10%

Question 90

How many % til COHb symptoms appear?

Answer 90

20-30%

Question 91

How many % til COHb cause coma, seizure, or death?

Answer 91

>40%

Question 92

COHb causes ___ discoloration of blood

Answer 92

cherry red color (skin also !)

Question 93

COHb is detected at __ nm spectral absorption

Answer 93

540

Question 94

Treatment for COHb

Answer 94

hyperbaric oxygen therapy