Biochem 1 USMLE Flashcards
full-term neonate of uneventful delivery becomes mentally retarded and hyperactive and has a musty odor. What is the d?
PKU
Stressed executive comes home from work, consumes 7 or 8 martinis in rapid succession before dinner, and becomes hypoglycemic. What is the mechanism?
NADH increase prevents gluconeogenesis by shunting pyruvate and oxaloacetate to lactate and malate
2 y/o girl has an increase in abd girth, failure to thrive and skin and hair depigmentation. What is the dx
kwashiorkor
alcoholic develops a rash, diarrhea, and altered mental status. What is the vitamen deficiency
vit B3 (pellagra)
51 y/o man has black spots in his sclera and has noted that his urine turns black upon standing. What is the dx
alkaptonuria
25 y/o male complains of severe chest pain and has xanthomas on his achilles tendons. What is the dz, and where is the defect?
familial hypercholesterolemia; LDL receptor
Condensed by (-) charged DNA looped twice around (+) charged H2A, H2B, H3, & H4 histone octamers (nucleosome bead). H1 ties nucleosmes together on a string (30-mm fiber). In mitosis, DNA condenses to form mitotic chromosomes.
Chromatin sx–image 77
note: Think of beads on a string
this type of chromatin is condensed, transcriptionally inactive
heterochromatin
this type of chromatin is less condensed, transcriptionally active
euchromatin
eu=true, “truely transcribed.”
purines are _____ & _____ and have _____ ring/s.
pyramidines are _____,_____, &______
A,G (2 rings)
C,T,U (1 ring)
mneu: PURe As Gold: PURines.
CUT the PY (pie)
Guanine has a _______
ketone
Thymine has a ______
methyl
mneu: THYmine has a meTHYl
Deamination of cytosine makes a _____
uracil
uricil is found in this nucleic acid
RNA
thymine is found in this nucleic acid
DNA
This bond has 3 H bonds and is therefore stronger that this bond which only has 2 H bonds
G-C bond > A-T
nucleotides with a higher G-C means a higher this
melting temperature
nucleotides are linked by this type of bond
3’-5’ phosphodiesterase bond
this refers to substituting purine for purine or pyrimidine for pyrimidine
transition
mneu: TransItion=Identical types
this refers to substituting purine for a pyrimidine or pyrimidine for purine
Transversion
mneu: TransVersion=conVersion between types
this feature of the genetic code refers to the fact that each codon specifies only 1 amino acid
unambiguous
this feature of the genetic code refers to the fact that more than 1 codon may code for the same amino acid
degenerate
the genetic code is universal (exceptions include mitochondria, archaeobacteria, mycoplasma, and some yeast) T or f
T
this mutation in dna often involves the same AA, it is often a base change in the 3rd position of codon (tRNA wobble).
silent