Flashcards in Biochem Deck (76)
I cell disease
Which way do Dynein and kinesin move?
Dynein moves retrograde (+ to -) and kinesin moves anterograde (- to +)
What does ouabain do?
Inhibits the na/k pump by binding to the K+ site
Where does hydroxyl action of collagen occur?
In the RER, specific proline and lysine residues are hydroxylated. Requires vitamin c (deficiency causes scurvy)
Where does glycosylation and the forming of collagen triple helices occur
In the RER. Problems firming this helix lead to osteogenesis imperfect a
What is Menkes disease?
X linked recessive connective tissue disease caused by impaired copper absorption and transport due to defective Menkes protein. Leads to decrease activity of Lysol oxidase
What is RNA interference?
DsRNA is synthesized that is complementary to the mRNA sequence of interest. When transfected into human cells, dsRNA separates and promotes degradation of target mRNA, "knocking down" gene expression
What is special about the inheritance of alpha-1 anti trypsin deficiency
The alleles are co-dominant
What is heteroplasmy?
Presence of both normal and mutated mtDNA, resulting in variable expression in mitochondria lily inherited disease
Enzymes that use thiamine
Pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, transketolase, branched-chain ketoacid dehydrogenase
Reactions vitamin B2 is used in
(Riboflavin) Used as cofactors in redox reactions, eg, the succinate dehydrogenase reaction in the TCA cycle
How is niacin made?
Derived from tryptophan. Requires B2 and B6.
How can you get a deficiency of niacin?
Hartnup disease (decreased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism), and isoniazid (decreased vitamin B6)
What reactions is B5 needed for?
(Pantothenic acid) Essential component of coenzyme A (CoA, a cofactor for acyl transfers) and fatty acid synthase
What is B6 used for?
Converted to pyridoxal phosphate (PLP), a cofactor used in transamination (eg. ALT and AST), decarboxylation reactions, glycogen phosphorylase. Synthesis of cystathionine, heme, niacin, histamin, and neurotransmitters including serotonin, epi, norepi, dopamine, and GABA
What is B7 used for?
(Biotin) Cofactor for carboxylation enzymes: pyruvate carboxylase, acetyl-CoA carboxylase, propionyl-CoA carboxylase
How can you get a deficiency of biotin?
Antibiotic use or excessive digestion of raw egg whites.
What reaction is B12 needed for?
Homocysteine to Methionine (homocysteine methyltransferase) and Methylmalonyl-CoA to Succinyl-CoA (methylmalonyl-CoA mutase [isomerase])
Interaction between Vitamin C and iron
Vitamin C facilitates iron absorption by reducing it to Fe2+ state
What is Vitamin C necessary for?
Hydroxylation of proline and lysine in collagen synthesis; necessary for dopamine beta-hydroxylate, which converts dopamine to NE
Rickets (vitamin D deficiency in children)
Type of anemia in vitamin E deficiency
Lab values in vitamin K deficiency
Increased PT and aPTT but normal bleeding time
Delayed wound healing, hypogonadism, decreased adult hair, dygeusia, anosmia, acrodermatits enteropathica. May predispose to alcoholic cirrhosis