BCM14

Question 1

What is chargraffs rule?

Answer 1

that the amount of pyrimidine =amount of purine in a dna strand
more specifcally
no.A=no.T
no. C= no. G

Question 2

what are the 3 forms of dna?

Answer 2

a
b
z

Question 3

describe b form

Answer 3

most common
right handed helix
10.5 bp per turn
wide=major
narrow = minor

Question 4

describe a form

Answer 4

shorter fatter
right handed helix
11bp per turn
deep= major 
narrow = minor

Question 5

describe z form

Answer 5

left handed helix
12 bp per turn
narrow = major
deeper = minor

Question 6

why are there major and minor grooves?

Answer 6

backbones closer on one side of the helix major far apart

minor close together. tfs bind major groove side because the backbones are not in the way.

Question 7

describe rna

Answer 7

single stranded with a right handed helical structure
base stacking van der wals
- ribose not deoxyribose
= more reactive than dna

Question 8

what does rna form with itself?

Answer 8

intramolecular helices

Question 9

what form is common for rna?

Answer 9

a form

Question 10

describe rna a form

Answer 10

right handed helix
11bp per turn
more equal grooves
bulges and breaks

Question 11

what are the 4 non standard nucleotides?

Answer 11

inosine
wybutosine
pseudouridine
methylated bases (5-methyluracil)

Question 12

where are all 4 bases distinguished?

Answer 12

major groove

Question 13

what is more reactive rna or dna

Answer 13

rna

Question 14

what is inosine used for?

Answer 14

The 3ʹ-base of an mRNA codon often makes no difference to the amino acid encoded
Inosine is used at the 5ʹ-end of the tRNA’s anticodon to reduce the number of different tRNA molecules the cell needs to make: wobble allows a single type of tRNA to pair with several different codons.
* aaRS = aminoacyl tRNA synthetase: enzyme that attaches amino acids to tRNAs.