DNA Structure & Chemical reactions of carboxylic groups

Question 1

DNA Function

Answer 1

Storage, transmission of genetic information

More stable than RNA

Question 2

Composition DNA

Answer 2

2 complementary DNA strands of opposite polarity
Twistet around common axis –> Right handed helix
Deoxyribose - Phosphate units located on outside, Bases on inside of double helix
Complementary bases interact via H BONDING

AT
AU
GC

Question 3

DNA helix turn

Answer 3

10 base pairs
3.4 nm

1000 –> 0.3 microm
3000 –> 1 mim

Question 4

Stability of double helix

Answer 4

H bonds btw. base pairs
Hydrophobic interactions
Hydrophilic interactions

Question 5

Hydrophobic interactions

Answer 5

Rings of nitrogenous bases are non polar –> Stacking interaction

Question 6

Hydrophilic interactions

Answer 6

Neg. charged phosphate groups

access to surrounding fluid

Question 7

Nucleotide

Answer 7

Pentose (deoxyribose)
Nitrogenous base
Phosphate group

(Zucker/Base/Phosphate)

Question 8

Nucleoside

Answer 8

Pyrimidine/ Purine base bound to sugar

BASE + SUGAR

Question 9

Bonds

Answer 9

N Glycosidic bond ( Natom of Base / C atom of sugar)

no free rotation about this bond

3-5 Phosphodiesterbond
–> Covalent, Phosphate group

Question 10

Chemical reactions of carboxylic groups

Answer 10

1. Salt
2. Acyl Halide
3. Amide formation
4. Anhydride
5. Ester
6. Nitrile