June 2015

Question 1

What molecules breaks down ATP

Answer 1

ATPase

Myosin head

Question 2

What molecule attaches to Z line at the end of the sarcomere

Answer 2

Actin

Question 3

Explain why muscle contraction is prevented if myosin molecules can’t bind to other myosin molecules

Answer 3

No thick filaments formed
So cannot pull down towards each other
So cannot shorten sarcomere

Question 4

A substance that prevents transcription attaches to cytosine and adenine.
How does this prevent expression of a gene

Answer 4

Prevents binding of transcription factors
Prevents complementary bases from paring
So no pre-mRNA made no translation

Question 5

If the question asks for a ratio, what do you do?

Answer 5

Ratio divide larger by smaller

It’s ok if the ratio isn’t whole number

Want to have numbers close to 1:as close to 1 as possible

Question 6

Suggest why damage to myelin sheaths of neurones can lead to problems controlling the contraction of muscles

Answer 6

Action potentials travel more slowly

So delay in muscle contraction

Question 7

Explain wbu hydrophobic molecules easily pass into neurones

Answer 7

They’re lipid soluble

Question 8

When cannabis binds to its receptor, it closes calcium ion channels. Suggest how this prevents muscle contraction

Answer 8

Prevents influx of calcium
No vesicles fuse so no neurotransmitter released
Pre-synapse remains polarised
No action potential generated

Question 9

Other than glucagon conversion etc,

How do you raise glucose levels naturally?

Answer 9

Amino acids and fatty acids get transformed into glucose

Gluconeogenesis

Question 10

When doing DNA locating,
they look at cells under an optical microscope

Explain why they used cells that were in mitosis

Answer 10

Chromosomes visible

So see where probe attaches