Nucleic Acids, ATP & Water

Question 1

Name one way, other than circular DNA, in which prokaryotic DNA differs from eukaryotic DNA

Answer 1

Not associated with histones

Question 2

If two organisms have a similar % of base pairs but are completely different, what’s responsible? (Following from a different order of base pairs)

Answer 2

Code for different AAs

Question 3

Why is DNA different in a virus?

Answer 3

A=/= T

DNA single stranded

Question 4

Events of interphase involve DNA replication, which involves…

Answer 4

Semi-conservative replication

Question 5

What does the graph show about root growth (graph of mitosis index vs distance from root tip)

Answer 5

Faster mitosis growth nearer to tip

So must grow via mitosis

Question 6

HSV attack’s nerve cells only. It has proteins complementary to what part of the nerve cell?

Answer 6

Receptors

Located on ITS membrane ONLY

Question 7

Describe an inactive virus

Answer 7

No more cells get infected

B/c virus not replicating

Question 8

List an advantage of programmed cell death

Answer 8

Stops virus replicating

Question 9

How does HSV microRNA allow it to stay in body for years

Answer 9

Binds via specific base pairing
Preventing mRNA from being read by ribosomes
Which prevents protein translation
That causes cell death

Question 10

Explain why DNA nucleotides are added in 5’ to 3’ direction only (1st mark)

Answer 10

Ref. to DNA polymerase

Question 11

State evidence that DNA is a polymer

Answer 11

Repeating nucleotides

Question 12

What is the minimum no. of DNA bases required to code for AAs if there are 51 AAs in the primary sequence?

Answer 12

153

Question 13

Why are there a more bases in a gene for a particular polypeptide than minimum?

Answer 13

Introns present

Question 14

Give one way in which ATP is good as a cell energy source?

Answer 14

Instantaneous release of energy

Question 15

How is ATP useful for biological processes?

Answer 15

Involves a simple reaction

Question 16

Why is it necessary for humans to synthesise large amounts of ATP

Answer 16

Can’t be stored

Small amounts of energy releases at a time

Question 17

Advantage of ATP as energy storage in cell

Answer 17

Easily hydrolysed

Question 18

Suggest how methylation of DNA prevents expression of gene

Answer 18

Prevents RNA polymerase binding
Which prevents complementary base pairing
So no translation of mRNA

Question 19

What is the role of RNA polymerase during translation

Answer 19

Joins nucleotides together to form mRNA

Question 20

What is meant by palindromic recognition sequence of DNA

Answer 20

DNA read the same both ways

Question 21

The movement of the woodlice in low relative humidity is an advantage to their survival. Explain how

Answer 21

Low humidity = more wood lice moving

Increased movement = increased chance of leaving dry which reduces water loss

Question 22

Explain why the following steps were necessary in finding the water content of straw:
(i)
heating the straw until it reaches constant mass

Answer 22

Ensure all water lost

Question 23

(ii) Not heating straw above 90

Answer 23

Only water given off

Above 90, straw burnt