RBCs

Question 1

Red blood cells

Answer 1

Specialized cells of the blood, function to carry O2 to tissues and carry CO2 away from tissues

Question 2

What are the features of the RBCs that aid their function?

Answer 2

Bi-concave shape
Lack of organelle
Metabolic function

Question 3

How are RBCs formed (erythropoiesis)?

Answer 3

Lack of O2 in tissues triggers the kidney to release a hormone erythropoietin (EPO)
EPO travls to the bone marrow and induces erythrocyte progenitor cells the multiply and differentiate into RBCs

Question 4

What are reticulocytes?

Answer 4

Young RBCs which which will still contain some organelles (mRNA, ribosomes, golgi)
24-48 hrs to mature

Question 5

If there in an inc in a reticulocyte count what could that indicate?

Answer 5

Chronic bleeding or hemolytic anemia

Question 6

If there in a dec in reticulocyte count what could that indicate?

Answer 6

Pernicious anemia or bone marrow dysfunction

Question 7

What does the biconcave shape do for the RBC?

Answer 7

Gas-exchange: max surface/volume ratio
Deformable: can move in capillaries
Survival in various osmotic pressure, room to swell

Question 8

Spherocytosis

Answer 8

Deformity in RBCs which leaves them spherical instead of biconcave
Results in anemia

Question 9

What the content make up of an RBC membrane?

Answer 9

50% lipid, 50% protein

Question 10

What are the lipids of the RBC membrane?

Answer 10

Cholesterol and phospholipid (PC, PE, PS, Sph)

Question 11

What are the major phopholipids comprising the RBC membrane?

Answer 11

Phosphatidylethanolamine (PE)
Phosphatidylcholine (PC)
Phosphatidylserine (PS)
Sphingomyelin (Sph)

Question 12

Which phosphates predominate in the out leaflet of the RBC bilayer?

Answer 12

Sph and PC

Question 13

What are glycoproteins and what amount of the total RBC lipid are they?

Answer 13

Factors comprising ABO blood groups

5-10%

Question 14

What are the most well known blood type groups?

Answer 14

ABO and Rb

Question 15

What is a blood group?

Answer 15

Antigens on the external surface of RBCs

Question 16

What are ABO substances comprised of?

Answer 16

Complex oligosaccharides

Question 17

If an allele codes for glycosyltransferase what blood type must that person have?

Answer 17

A or B

O is the deletion of the gene

Question 18

What are the key proteins in and around the RBC membrane?

Answer 18

Spectrin, ankyrin, band 3 (anion exchange protein), glycophorins, 4.1

Question 19

What is the main function of Band 3?

Answer 19

Chloride-bicarbonate exchanger of the cell
Anchors to membrane skeleton by ankyrin
Regulation of ion content, deforms cell, metabolism

Question 20

What are the functions of glycophorin?

Answer 20

Largest component of integral membrane proteins
High sialic acid content (surface charge)
Stability of membrane, deform cell, shape

Question 21

What are the functions of ankyrin?

Answer 21

Pyramid-shaped
Binds to band 3 and spectrin
Maintain cell shape

Question 22

What are the functions of 4.1?

Answer 22

Contain spectrin-actin binding site
Linkage of spectrin-actin membrane skeleton to lipid bilayer via linkage to band 3 and glycophorins
Membrane deformability and resilience

Question 23

What is spectrin and what does it do?

Answer 23

Peripheral membrane protein, comprise of alpha and beta heterodimers
Modulation of cell shape

Question 24

What are the protective enzymes in RBCs?

Answer 24

Superoxide dimutase (transition of ROS)
Catalase (H2O2 to O2 and H2O)
Glutathione reductases (GSSG to GSH)

Question 25

What is methemoglobin (metHb) form by?

Answer 25

Auto-oxidation of Fe2+ in hemoglobin to Fe3+

Question 26

What is the problem with metHb?

Answer 26

Can't transport oxygen

Question 27

How do RBCs change from metHb to normal Hb?

Answer 27

NADH-cytochrome b5 metHb reductase system (off-shoot of glycolysis)

Question 28

How could someone have a metHb anemia?

Answer 28

Inherited - deficiency of cytochrome reductase or others | Acquired - ingestion of chemicals (sulfanoamides/anilines)

Question 29

How are metHb anemias treated?

Answer 29

Administering oral or IV of methylene blue or ascorbic acid

Question 30

What is the importance of the hexose monophosphate shunt?

Answer 30

Generates NADPH by glucose that is moved in | Maintains glutathione in reduced state (GSH)

Question 31

Which step in glycolysis can cause anemia if deficient?

Answer 31

G6PD

Question 32

What is the importance of the Rapoport-Luberin shunt?

Answer 32

Generates 2,3-bisphosphoglycerate | Can moderate the binding of O2 to Hb

Question 33

Heme

Answer 33

4 polypeptide chains surrounding a porphyrin ring

Question 34

Describe heme synthesis

Answer 34

Start with succinyl Co-A, condenstation of the pyrrole rings

Question 35

What are porphyrias?

Answer 35

Diseases resulting from errors in here metabolism | Typically genetic

Question 36

How is heme degraded?

Answer 36

Globins are recycled by making heme into bilirubin and is then transported to the liver and excreted as bile

Question 37

How can you fix jaundice in newborns?

Answer 37

Phototherapy