Block A

Question 1

During intron splicing, what site does the splicing proteins recognise

Answer 1

The GU site at the 5’ splice site

Question 2

During intron splicing, what happens after the splicing proteins recognise the specific site

Answer 2

The proteins recruit other proteins into a large complex called the spliceosome

Question 3

Which bases are purines

Answer 3

Guanine, Adenine

Question 4

Which bases are pyrimidines

Answer 4

Cytosine, Thymine

Question 5

Whats a nucleoside

Answer 5

Base conjugated to a sugar

Question 6

Whats a nucleotide

Answer 6

Nucleoside conjugated to 1 or more phosphates

Question 7

How many H bonds in a G-C

Answer 7

3

Question 8

How many H bonds in a A-T

Answer 8

2

Question 9

Which is harder to break, G-C or A-T

Answer 9

G-C

Question 10

Introns are ____ regions

Answer 10

Non-coding (intervening DNA)

Question 11

Extrons are _____ regions

Answer 11

Coding (Expressed DNA)

Question 12

In DNA replication, how is RNA primer produced and state its role

Answer 12

RNA primer provides a starting point for DNA replication. Produced by primase

Question 13

In DNA replication, which enzyme catalyses specific DNA bases to the free 3’ hydroxyl on the primer

Answer 13

DNA polymerase

Question 14

Whats the role of mRNA

Answer 14

Template for the synthesis of proteins

Question 15

Whats the role of tRNA

Answer 15

Carries amino acids to ribosomes in translation

Question 16

Whats the role of rRNA

Answer 16

A major component of ribosomes

Question 17

Describe the initiation phase of transcription

Answer 17

The binding of transcription factors to certain gene sequences (like CAAT box and TATA box) at the promotor site opens the DNA and phosphorylates the carboxyl-terminal domain (CTD). This allows RNA polymerase II to leave the promotor site and begin transcription.

Question 18

How many base pairs need to be open for the promotor site to be open

Answer 18

17

Question 19

Describe the elongation phase of transcription

Answer 19

RNA poly II moves along DNA template to synthesize mRNA, growing in a 5’ to 3’ direction

Question 20

Describe the termination phase of transcription

Answer 20

RNA polymerase ceases transcription at defined sites. mRNA strand is stabilised by modifications like 5’ cap and poly A tail at 3’

Question 21

Whats the equation for Aminoacyl tRNA synthetases

Answer 21

Amino acid + ATP +tRNA +H²0 –> Aminoacyl-tRNA + AMP + 2Pi

Question 22

Describe how Translation is initiated

Answer 22

Initiated through a complex. This complex scans the mRNA, looking for an AUG codon. Once found, an 80S is formed on the ribosome and protein synthesis begins.

Question 23

What is intercellular signalling

Answer 23

Communication between different cells

Question 24

Whats intracellular signalling

Answer 24

Signalling within the cell

Question 25

Define epigenetics

Answer 25

Modifications to the genome that affect gene expression but do not alter the DNA sequence

Question 26

When CpG is methylated, the ____ is methylated

Answer 26

Cytosine

Question 27

Explain how methylation of CpG regions repress gene expression

Answer 27

Methyl binding proteins bind to methylated DNA and prevent the binding of transcription factors.

Question 28

Describe how DNA is packaged in the nucleus

Answer 28

DNA wraps around a histone octomer. A histone octomer is four histone units assembled.

Question 29

Whats the name for a DNA-histone complex

Answer 29

Chromatin

Question 30

Describe the properties of euchromatin (3 marks)

Answer 30

-loosely packed -under active transcription -enriched in genes

Question 31

Describe the properties of heterochromatin (3 marks)

Answer 31

-tightly packed form of chromatin -inaccessible to transcription factors -genetically inactive

Question 32

What determines the state of the chromatin

Answer 32

Methylation and acetylation of histones

Question 33

How can epigenetic changes cause disease

Answer 33

The methylation of a tumor suppressor gene could inhibit gene expression. This could lead to cancer.

Question 34

Give an example of how RNA interference (RNAi) may be used experimentally

Answer 34

It can be used to knockdown protein production from a particular gene

Question 35

Outline the experimental use of CRISPR-Cas?

Answer 35

To generate genetic mutations at a desired location in the genome

Question 36

How does CRISPR-Cas complex target specific regions of the genome

Answer 36

with a guide RNA that is complementary to the target DNA sequence

Question 37

Why does the movement of electrons from glucose to oxygen release energy

Answer 37

because oxygen has a higher redox potential than glucose

Question 38

TRUE/FALSE: RNA polymerase II is located only in the cell cytosol

Answer 38

false

Question 39

TRUE/FALSE: RNA polymerase II synthesizes RNA in a 3' to 5' direction

Answer 39

false

Question 40

TRUE/FALSE: RNA polymerase II transcribed genes encoding aminoacyl tRNA synthetases

Answer 40

true

Question 41

Put the following events (1-5) in the correct order: 1. Splicing 2. Elongation 3. Capping 4. Initiation of transcription 5. Assembly of the basal transcription complex

Answer 41

5,4,3,2,1

Question 42

TRUE/FALSE: Cytosolic proteins are always membrane bound

Answer 42

false

Question 43

TRUE/FALSE: Cytosolic proteins are polar on the surface

Answer 43

true

Question 44

Is the conversion of ADP to ATP carried out by the electron transport chain

Answer 44

no

Question 45

What is the correct order of events in the chain elongation part of the fatty acid synthesis pathway.

Answer 45

Condensation, reduction, dehydration, reduction

Question 46

PCR is used to indentify microsatellite variation between individuals because....

Answer 46

PCR product size differences indicate microsatellite variation

Question 47

A father will share ____ of his genetic variation with his child.

Answer 47

50%