Introduction to DNA

Question 1

Name the tightly packed DNA in SOLENOID form

Answer 1

Heterochromatin, INACTIVE

Question 2

How many genes in the human genome

Answer 2

25,000

Question 3

A phosphate, sugar, base molecule is called?

Answer 3

Nucleotide

Question 4

What is a solenoid?

Answer 4

DNA around histone core, beads on a string, folded up

Question 5

How many chromosomes are there?

Answer 5

23 pairs, 22 autosome pairs, 2 sex chromosomes X and Y

Question 6

What is Euchromatin?

Answer 6

DNA wrapped around a histone core forming a nucleosome, beads on a string, in the nucleus, ACTIVE

Question 7

Name the sugar in a RNA nucleotide

Answer 7

Ribose

Question 8

Name the sugar in a DNA nucleotide

Answer 8

2-deoxyribose

Question 9

What is DNA ligase?

Answer 9

facilitates the joining of DNA strands together by catalysing the formation of a phosphodiester bond

Question 10

Nucleotides are joined via?

Answer 10

phosphodiester bonds, between phosphate + sugar

Question 11

What is DNA helicase?

Answer 11

enzyme, unwinds DNA double helix

Question 12

Nucleotide bases join via?

Answer 12

hydrogen bonds (G,C 3 bonds) (A,T,U 2 bonds)

Question 13

Name the purines and pyrimidines

Answer 13

Purines: adenine, guanine. Pyrimidines: cytosine, uracil, thymine

Question 14

Name the stages of prokaryotic replication

Answer 14

Initiation –> elongation –> termination

Question 15

What is primase?

Answer 15

Kick starts DNA replication by binding a DNA primer

Question 16

DNA replication catalysed by?

Answer 16

DNA polymerase (extends 3’-5’, synthesises 5’-3’)

Question 17

What are okazaki fragments?

Answer 17

newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication

Question 18

What is the length of DNA in each cell?

Answer 18

2 metres

Question 19

What form is DNA in when active?

Answer 19

Euchromatin

Question 20

What is the difference between active and inactive DNA?

Answer 20

active = acetyl groups, inactive = methyl groups

Question 21

what is a nucleoside?

Answer 21

base and sugar, no phosphate

Question 22

what is the difference between purines and pyrimidines?

Answer 22

purines are bigger as they have 2 loops

Question 23

what is epigenetics?

Answer 23

whether or not genes are expressed due to the structure of the chromatin

Question 24

the phosphate and sugar join at which carbons

Answer 24

5th C and 3rd C (OH)

Question 25

how many bonds to G-C make?

Answer 25

3

Question 26

how many bonds do A-T make?

Answer 26

2

Question 27

the structure of the complimentary strand to the DNA stand can be described as?

Answer 27

anti-parallel

Question 28

what type of helix is a DNA helix?

Answer 28

right-handed double helix containing anti-parallel strands

Question 29

what direction do you write DNA in?

Answer 29

5’-3’