Week 4-7

Question 1

What are operons

Answer 1

A group of structural genes plus sequences that control transcription

Question 3

True or false some viruses can copy rna from rna

Answer 3

Yes they can undergo rna replication

Question 4

What are the only 3 RNAs that are in both eukaryotes and prokaryotes

Answer 4

mRNA
rRNA
tRNA

Question 5

What are the 6 types of RNAs that are found in eukaryotes only

Answer 5

Pre mRNA
SnRNA
SnoRNA
microRNA
Small interfering rna siRNA
Pwiwpinteracting rna piRNA

Question 6

The type of rna that only prokaryotes make during transcription

Answer 6

CRISPR RNA

Question 7

What are the structural and functional components of ribosomes

Answer 7

Ribosomal rna

Question 8

Which rna polymerase helps to destroy transposable elements in the reproductive cells

Answer 8

Piwi rna

Question 9

Which rna polymerase assists in the destruction of FOREIGN DNA

Answer 9

CRISPR RNA

Question 10

Which rna polymerase plays a role in rRNA processing

Answer 10

Small NUCLEOLAR RNA

Question 11

Which rna polymerase plays a role MRNA processing by forming part of the spliceosome

Answer 11

Small NUCLEAR RNA

Question 12

Which rna polymerase assists in the destruction of other rna molecules

Answer 12

Small INTERFERING rna

Question 13

What is the site of initiation of transcription

Answer 13

The promoter

Question 14

Whats the purpose of adding the 5’ cap

Answer 14

Protection
Helps the ribosome to bind to the 5’ end of the mRNA
Helps in export
Stabilises the mRNA

Question 16

What are the two functions of dna methyl transferases

Answer 16

Helps bind methyl to dna
Recruits HDAC’s to tighten the chromatin structure

Question 17

Name the two ways in which dna methylation can come about

Answer 17

De novo DNA methylation (during early development )
Through inheriting dna methylation patterns during cell division

Question 18

Whats the purpose of 3’ cleavage and the addition of poly A tail

Answer 18

Stabilises mRNA
Helps ribosomes to bind to mRNA

Question 19

Whats the purpose of rna splicing

Answer 19

Removes the non coding introns and joins exons
Allows us to form a lot of proteins with a single gene via ALTERNATIVE SPLICING

Question 20

What has to occur before you can add the adenine nucleotides during polyadenylation

Answer 20

The pre mRNA has to be cleaved at the 3’ cleavage site which is downstream the consensus sequence

Question 21

What has to occur before the 5’ guanine nucleotide is added

Answer 21

One phosphate of the first nucleotide has to be removed at the 5’ end

Question 22

What does the new guanine nucleotide become after methylation

Answer 22

7- methyl guano sine

Question 23

Name the 3 different types of sites that are present during splicing

Answer 23

Splice donor site
Branch site
Splice acceptor site

Question 24

The steps of splicing in order of occurrence

Answer 24

Capping
Cleavage
Polyadenlation
Splicing
Export

Question 25

DEFINE ALTERNATIVE SPLICING

Answer 25

When you create multiple mRNAs from one gene by linking different combinations of exons and thus making many different proteins

Question 26

Give an example of hat could happen if the slice sites are mutated

Answer 26

If slice sites are mutated its could lead to the production of a non functional or harmful protein being formed An example is seen in the alternative splicing of MYOSTATIN, the normal alternative splicing product is a functional myostatin protein that stops muscle growth however if its mutated leads to the formation of a NON FUNCTIONAL PROTEIN that leads to MUSCLE HYPERTROPHY where muscles don’t stop growing

Question 27

The direction in which the polypeptide chain is made during translation

Answer 27

From the amino side to the carboxylic side

Question 28

How many protein factors are involved in the initiation of transcription in prokaryotes and eukaryotes respectively

Answer 28

3 and about 12

Question 29

In prokaryotes what helps the ribosome to position itself correctly to the mRNA

Answer 29

The shine dalgarno sequence

Question 30

In eukaryotes what helps the ribosome to position itself correctly on the mRNA

Answer 30

The 5’ cap / 7- methylguanosine

Question 31

In eukaryotes what helps the ribosome recognise the Start codon

Answer 31

The kozak sequence

Question 32

What amino acid does AUG code for in prokaryotes and eukaryotes respectively during translation

Answer 32

N-formylmethionine and methionine

Question 33

How many release factors are there in prokaryotes during termination

Answer 33

3

Question 34

What does each one recognise or bind to?

Answer 34

RF 1- recognises UAA & UAG RF2 - recognise UAA & UGA RF3- removes RF1 and RF2

Question 35

How many release factors are in eukaryotic translation termination

Answer 35

2

Question 36

What are their names and functions

Answer 36

eRF-1 : recognises all 3 stop codons eRF-2 : removes the polypeptide chain from ribosome

Question 40

Which enzyme catalyses the nucleophillic attack by the 3-OH at the primer end terminal on the alpha phosphate of the incoming dNTP that is based paired with the template

Answer 40

DNA polymerase (this is dna replication )

Question 41

Which 3 proteins are common in both during dna replication

Answer 41

Helicase SSB DNA ligase