RNA Translation & Protein Targeting

Question 1

What synthesises proteins from RNA

Answer 1

Ribosomes synthesise proteins from RNA

Question 2

Define ribosome

Question 3

What is always the start codon of a sequence (for DNA vs RNA)

Answer 3

ATG= start codon for DNA
AUG = start codon for RNA

Question 4

What are the 3 stop codons for DNA vs RNA

Answer 4

DNA= TAA, TGA, TAG stop codons

RNA= TAA, UGA, UAG stop codons

Question 5

What is messenger RNA (mRNA)

Question 6

What is Ribosomal RNA (rRNA)

Question 7

What is Transfer RNA (tRNA)

Question 8

What type of RNA helps catalyst formation of peptide bonds between amino acids

Answer 8

Ribosomal RNA

Question 9

Where is rRNA found

Answer 9

rRNA is found in ribosomes

Question 10

What happens at the A site (aminoacyl-tRNA binding site ) on the ribosome

Answer 10

At the A site, tRNA attached to amino acid

Question 11

What happens at the P site (Peptidyl-tRNA binding site) on the ribosome

Answer 11

At the p site peptide bonds are formed

Question 12

What happens at the E site (Exit site) on a ribosome

Answer 12

At the E site, tRNA will leave (exit) ribosome so it can be used again

Question 13

Functions of tRNA

Answer 13

Acts to translate between RNA and amino acid

Question 14

1 end of the tRNA is attached in to a specific amino acid. What enzyme is this attachment catalysed by?

Answer 14

1 end of tRNA is attached to specific amino acid. This attachment is catalysed by AMINOACYL tRNA SYNTHASE

Question 15

Function of aminoacyl RNA transfer synthase

Answer 15

ERROR CHECKING
= corrects its own errors, adds correct aa onto the tRNA

I.e. incorrect aa removed by hydrolysis as enzyme can proof read incorrect aa’s

Question 16

What is meant by the DNA code being DEGENERATE

Question 17

How many hydrogen bonds between G and U

Answer 17

2 H bonds between G and U

Question 18

Summarise the process of translation

Answer 18

1) mRNA binds to a specific site on small subunit of ribosome

2) INITIATION: Transitional complex forms & tRNA brings amino acid to bind to start codon on mRNA. tRNA anticodon attached to mRNA(on ribosome) by complementary base pairing

3) ELONGATION: tRNAs keep bringing new aas. rRNA catalyses formation of peptide bonds between aa’s— producing polypeptide chain

4) TERMINATION: release factor recognises stop codon. Translational complex dissociates, components recycled. Complete polypeptide released

Question 19

Describe initiation in translation

Question 20

Describe elongation in translation

Question 21

Describe termination in translation

Question 22

Explain protein targeting with examples

Question 23

How can differences in eukaryotic + prokaryotic translation be exploited for medical intervention?