Random knowledge 1st test

Question 1

How many base pairs per turn of DNA helix

Answer 1

about 10

Question 2

DNA helix is left or right handed

Answer 2

right handed

Question 3

structural RNA

Answer 3

tRNA, rRNA, snRNA (small nuclear), snoRNA (small nucleolar RNA)

Question 4

Regulatory RNA

Answer 4

miRNA (micro RNA), siRNA (small interfering RNA)

Question 5

Information containing RNA

Answer 5

mRNA

Question 6

Eukaryotic topoisomerase
Type I and II

And… what is the prokaryotice topoisomerase called?

Answer 6

Relieves torsional strain in replication
Type I: cuts 1 strand and moves
Type II: cuts both strands

Prokaryotic topoisomerase = gyrase

Question 7

DNA Pol I

Answer 7

In prokaryotes

• distributive, no sliding clamp, slow
• replaces RNA primers
• does have proofreading (3’-5’ and 5’-3’)

Question 8

DNA Pol III

Answer 8

Prokaryotic

• “processive” with sliding clamp, fast
• doesn’t remove RNA primer (no 5’-3’ exonuclease)

Question 9

How to add 5’ cap (3 steps)

Answer 9

1. Take off phosphate
2. Add GTP backwards, remove 2 P -> GMP
3. Methylate 7’ position

–> 5’ cap 7-methylguanosine

Question 10

GU

Answer 10

conserved sequence beginning of intron (5’ part of intron)

take it off!

Question 11

AG

Answer 11

conserved sequence end of intron (3’ end)

take it off!!!

Question 12

consensus poly A initiation

Answer 12

AAUAAA

Question 13

U1 snRNA

Answer 13

binds GU 5’ splice site

Question 14

U2 snRNA

Answer 14

binds branch point A

Question 15

U2 AF protein

Answer 15

binds AG 3’ intron spice site

Question 16

Id protein

Answer 16

downregulate DNA binding. They are a member of Helix-Loop-Helix family and they dimerize (but they don’t have the necessary basic part of bHLH).

Question 17

CREB modification

Answer 17

CREB + phosphorylization -> pCREB -> recruits CBP (which is a HAT) -> recruits RNA pol-II -> activates gene expression

Question 18

prokaryotic IF’s

Answer 18

IF 1 and 3 bing 30S subunit bring it to RNA.

IF 2 brings formylmethionine

Question 19

Alpha helix secondary structure

Answer 19

H bonds, turn = 3.6 residues (5.4 angstroms)
Fits well into dsDNA

H bonds formed between n and n+4

Question 20

Collagen chain

Answer 20

individual chain is L handed, but 3 collagen chains form R handed triple helix

Collagen is proline and glycine rich

in connective tissue (tendons/cartilage/bone/cornea of eye)

Question 21

keratin

Answer 21

in hair and nails

Question 22

Kd

Answer 22

Kd = dissociation constant of protein-ligand

Kd= [ligand] at which 1/2 protein is bound

Question 23

groEL

Answer 23

chaperone that encapsulates proteins to help them fold

Question 24

Hsp70

Answer 24

chaperone that binds hydrophobic areas of proteins to prevent aggregation

Question 25

prolyl isomerase

Answer 25

catalyze conversion trans/cis of proline

Question 26

protein disulfide isomerase

Answer 26

catalyze disulfide formation between cysteins