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11 Cards in this Set

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Biotin is involved in what 2 reactions?

What is the regulation point for FA synthesis in the liver?

Pathway for making methyl-FH4?

What provides 1-carbon units to attach to folate?
carboxylation reactions - pyruvate carboxylase, Acetyl-CoA carboxylase

Acetyl-CoA carboxylase

FH4 --> formyl-FH4 --> methenyl-FH4 --> methylene-FH4 --> methyl-FH4

serine, glycine, histidine, Trp (makes formate)
What two stages of the folate pathway are critical to DNA synthesis?

Which step is unidirectional in the pathway?

General function of S-adenosyl methionine (SAM)?

How is methyl-FH4 involved with SAM? What cofactor is needed?
formyl-FH4 and methylene-FH4

unidrectional - methylene-FH4 --> methyl-FH4

donates methyl groups

SAH gets -CH3 from methyl-FH4, and needs B12 to shuttle the -CH3
B12 is similar in structure to what? What is the ion in the middle?

What two reactions is B12 involved in?

Deficient B12 causes what to happen to folate? What does this lead to?
heme - Cobalt instead of Iron

L-methylmalonyl-CoA --> succinyl-CoA, homocysteine --> methionine (releases free FH4)

methyl-folate trapping - functional folate deficiency
leads to megaloblastic anemia, NTD's
A deficiency in ________ leads to pernicious anemia. What test do you use to check this?

Betaine acts as ______ in the homocysteine --> methionine reaction.
intrinsic factor

Schilling's test
Hemolysis of RBC's causes what to be released? What does this do to the body?

What scavenges Hgb, heme, and Fe2+ in the body?

In SCD, what does the Glu-6-Val do to the structure of hemoglobin?
Hgb, heme, Fe2+ --> increased free radical formation

Hgb - haptoglobin
Heme - hemopexin
Fe2+ - transferrin

changes charged acid (Glutamine) to lipid-like (Valine)
Which Hgb?
1. African SCD:
2. Glu-6-Lys, African:
3. Glu-26-Lys, Asian:
4. Glu-121-Gln, Indian/Pakistani:

Lab changes in SCD?

Treatments?
1. Hgb S
2. Hgb C
3. Hgb E
4. Hgb D

decreased H&H, increased total bili

O2 by nose, bydroxyurea, transfusions if severe
Three causes of methemoglobinemia?

Met-Hgb-emia causes _______, not hemolytic anemia.
Hgb M - genetic deficiency
Met-Hgb reductase deficiency
Chemicals - nitrates, nitrites, aniline dyes

cyanosis
Decreased production of globin chains:

How is the gene changed in thalassemias?

Which Hgb's are in B-thal major, minor, A-thal?
Thalassemia

new splice site either inactivates or changes the exons

B-thal major - Hgb A, Hgb F (90%), Hgb A2
B-thal minor - same
A-thal - Hgb Bart's (homozygous fetal), or Hgb H (4 B chains)
Most common defect in hereditary spherocytosis? What are other gene defects?

Spherocytosis RBC's generally have a higher _______ _______.
A-spectrin most common; also B-spectrin, Band 3, Ankyrin

osmotic fragility
G-6-PD deficiency is involved in what pathway?

A defect in NADPH has what effect on RBC's?

What are some chain-breaking anti-oxidants?
Pentose Phosphate Pathway

NADPH - protects against ROS, so increased damage from ROS

Tocopherols (Vitamin E), Ascorbate (Vitamin C), glutathione system
You will see _______ bodies in G-6-PD.

Characteristics of pyruvate kinase deficiency?

Which ion is particular affected?

How is the RBC affected by pyruvate kinase deficiency?
Heinz bodies

decreased ATP use, so no protein synthesis, motility, AP's, ionic gradients

Calcium

increased fragility of membranes --> increased destruction