Lecture 1

Question 1

Phosphodiester bond numbers

Answer 1

5 hydroxyl and 3 hydroxyl

Question 2

Most common DNA form

Answer 2

B form

Question 3

Is the number of A equal to T

Answer 3

Yes

Question 4

Bonds between bases
Stacking forces
Balanced by

Answer 4

Vanderwaals
Hydrophobic interactions
Repulsive forces from the -ve charge on the phoshates

Question 5

B form

Answer 5

Right handed
10.4 bp per turn
2nm diamtere

Question 6

Size of major vs minor grooves
function

Answer 6

Major 2.2 nm
Minor 1.2 nm
Allow drugs and enzymes to access the DNA and reach the bases without unwinding

Question 7

Only left handed form of DNA is

Answer 7

Z form

Question 8

A form function

Answer 8

*Regulates genes expression by controlling the extent of regulating proteins binding to DNA

*Moderately dehydrated chromatin
*DNA -RNA hybrid
*RNA-RNA double stranded regions

Question 9

Form of DNA has mainly c and g

Answer 9

Z form

Question 10

Z form length
Place

Answer 10

Long and thin
12-24 bp stretches
5’ end of genes for regulation of transcription

Question 11

Tertiary DNA structure
Common form of supercoil why?

Answer 11

Linear/circular
Negative
Easier for transcription

Question 12

Dna coils….handed around histones that makes it…..supercoiled

Answer 12

Left
Negatively

Question 13

Exception in some viruses

Answer 13

Single stranded DNA

Question 14

Gene expression is affected by …and…

Answer 14

Type of double helix and type of supercoiling

Question 15

Mitochondrial DNA is…. Of cellular DNA
Controls synthesis of…….
Involved in….
….inhereted and used for …
Mutations =..

Answer 15

0.3-1%
2 rRNA/22tRNA/13 proteins
Oxidative phosphorylation
Maternally, maternal lineage
Myopathies

Question 16

Heat affects
Denaturation of DNA causes

Answer 16

Hydrogen bonds causing strands ro separate
Increased UV absorption at 260 nm
Hyperchromicity
Decreased viscosity

Question 17

Temp that cause 50 percent damage to dna and loss of double helix is
Increases when…

Answer 17

Melting temp
Lower AT bonds
Low alkaline medium
High salt conc

Question 18

Function of nucleic acids

Answer 18

Storage and transfer of information for protein synthesis

Question 19

The nitrogenous bases are

Answer 19

Pointed 90°

Question 20

Direction of synthesis is

Answer 20

5’ to 3’

Question 21

Both DNA strands are

Answer 21

Complementary to each other

Question 22

Supercoil types

Answer 22

+ve
-ve
Toroidal around a cylindrical object/histones
Interwound, around itself

Question 23

Eukaryotes have..DNA in mitochondria
Prokaryotes have

Answer 23

Closed circular
Single, double stranded,supercoiled circular chromosome+ extrachromosomal DNA/ plasmid

Question 24

What does the plasmid contain

Answer 24

Antibiotic genes