Molecular Inheritance

Question 1

Who discovered nucleic acid?

Answer 1

Miescher

Question 2

What did miescher and other scientists discovered nucleic acid was composed of?

Answer 2

A 5 carbon sugar
Nitrogenous base
Phosphate

Question 3

What do chromosomes contain?

Answer 3

DNA and protein

Question 4

What is a bacteriophage?

Answer 4

A type of virus composed of DNA and protein which infects bacterial cells

Question 5

What is the pentose sugar in DNA?

Answer 5

Deoxyribose

Question 6

Which bases are the purines?

Answer 6

Adenine and Guanine

Question 7

What bases are the pyrimidines?

Answer 7

Cytosine and Thymine

Question 8

What bond join the phosphate backbone?

Answer 8

Phosphodiester bond

Question 9

Who discovered that bases would only fit if purine was paired with pyrimidine?

Answer 9

Watson and Crick

Question 10

How many hydrogen bonds are between C-G?

Answer 10

3

Question 11

How many hydrogen bonds are between A-T?

Answer 11

2

Question 12

Who proposed the idea of semi conservative replication?

Answer 12

Watson and Crick

Question 13

Who proved semi conservative replication?

Answer 13

Meselson and Stahl

Question 14

What does DNA polymerase require?

Answer 14

Single-stranded template DNA
All four nucleoside triphosphates (dNTPs)
Free 3’ hydroxyl (primer)

Question 15

In what direction is DNA synthesised with DNA polymerase?

Answer 15

5’ to 3’

Question 16

Describe Mieschers experiment

Answer 16

Pus from used bandages
Collected white blood cells
Purified nuclei
He found an N rich fraction (protein) and a P rich fraction (nucleic acid)

They thought the protein was the nucleic acid

Question 17

What did Chargaff discover

Answer 17

A and T, C and G pairings

Question 18

What did Avery conclude?

Answer 18

Transforming principle is DNA

Question 19

What was Griffins experiment?

Answer 19

Used a benign and virulent strand
Virulent (s) is killed
Genetic material was capable of reprogramming R form into S form

Question 20

What are the 3 components of a nucleotide?

Answer 20

5 carbon sugar
Nitrogenous base
Phosphat

Question 21

How wide is DNA?

Answer 21

2nm

Question 22

What is the length of each turn?

Answer 22

3-4nm

Question 23

What is the distances between repeating units/ nucleotides?

Answer 23

0.34nm

Question 24

How many nucleotide pairs are there per turn?

Answer 24

10

Question 25

Define semi conservative replication

Answer 25

Each stand acts as a template for synthesis of a new complementary strand of DNA

Question 26

What is the role of helicase?

Answer 26

Unwinds helix to open DNA

Question 27

What is the role of primase?

Answer 27

Synthesises RNA primers

Question 28

What is the role of DNA polymerase III?

Answer 28

Extends DNA strand from 3’ end, copying the template

Question 29

What is the role of DNA polymerase I?

Answer 29

removes RNA primer and fills gaps between okazaki fragments

Question 30

What is the role of DNA ligase?

Answer 30

Seals gaps between okazaki fragments

Question 31

What is the role of single stranded binding proteins?

Answer 31

Holds helix open

Question 32

How does the lagging and the leading strand differ?

Answer 32

The lagging strand synthesises discontinuously and the leading strand synthesises continuously

Question 33

What enzyme proofreads to remove incorrect nucleotides?

Answer 33

DNA polymerase