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11 Cards in this Set
- Front
- Back
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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) |
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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 |
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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 |
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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 |
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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) |
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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 |
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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 |
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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) |
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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 |
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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 |
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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 |
