biocehm rull quick

Question 1

Protein synthesis

Answer 1

CCA binds methionine on 3’ end of tRNA –> initiation tRNA. 30 S on ribosome contains 16 s rRNA which is complementary to sequence upstream of AUG (start), binds. Then, initiator tRNA (the methionine one) binds AUG and the 50S subunit joins –> start synthesis! Need 50S to join because 50S has 23S rRNA, which does peptide bond formation. Assembly. Then elongation, tRNA binds A site and transfers P to A and then A moves to P and P leaves. Stop codons = UGA, UAA, UAG (you go away, you are away, you are gone).

Question 2

ATP vs GTP in protein synthesis

Answer 2

ATP does tRNA Activation, GTP does tRNA gripping and going places (translocation)

Question 3

Beta sheet and alpha helix are which level protein structure?

Answer 3

2. H bonding. This is the problem is Alzheimers (beta amyloid).

Question 4

Vimentin stains for what cell type? Desmin?

Answer 4

Vimentin –> connective tissue. desmin –> muscle

Question 5

Problem in collagen formation with OI

Answer 5

Triple helix formation via glycosylation of alpha chains. This is inside fibroblasts

Question 6

Indirect vs direct ELISA

Answer 6

Indirect detects antibodies, direct detects antigens. Incredibly sens and spec (use for HIV)

Question 7

Pleiotropy

Answer 7

One gene contributes to multiple phenotypic effects

Question 8

Dominant negative mutation

Answer 8

Heterozygotes –> mutated protein gets in the way of normal one working correctly (ie transcription factor that is mutated blocks DNA binding site for normal one)

Question 9

Main function of nucleolus

Answer 9

make rRNA.

Question 10

How does streptomycin work

Answer 10

Blocks 30S to block initiation of protein synthesis

Question 11

DM, necroyltic erythema, anemia

Answer 11

Glucagonoma

Question 12

Drug induced lupus drugs are metabolized how?

Answer 12

Acetylation in liver. Hydralazine and procainamide

Question 13

Pt in hospital has poor appetite. Skin peeling on back and butt and pitting edema, looks potbellied. Hair is light at base and can be plucked painlessly. Low albumin and high urea excretion.

Answer 13

Kwashiorkor. Protein malnourishment. Urea formed from excess breaking down of proteins to make up for dietary deficit. Light hair from lack of melanin (lack of tyrosine). Lose visceral proteins, don’t lose skeletal muscles, so won’t look emaciated. MARASMUS is low TOTAL calorie intake –> will look emaciated.

Question 14

Elastin vs collagen

Answer 14

Elastin has no triple helix, lysine crosslinking instead of hydroxylation

Question 15

Highest rate of metabolism sugar?

Answer 15

Fructose 1 p because bypasses PFK, RLS! Goes straight to fructose 1,6 BP or glyceraldehyde 3P