Gene expression

Question 1

Function of tRNA

Answer 1

Carries specific amino acid to the ribosome

Question 2

Triplet bases of bases in mRNA and tRNA

Answer 2

mRNA - codon
tRNA - anticodon

Question 3

site of translation

Answer 3

ribosome in cytoplasm

Question 4

Sub-units that join together to form a polypeptide

Answer 4

amino acids

Question 5

Bond that joins amino acids together

Answer 5

Peptide bonds

Question 6

Bonds that hold proteins in their 3D shape

Answer 6

Hydrogen bonds
Other interactions

Question 7

3 differences between DNA and RNA

Answer 7

DNA: Double stranded, deoxyribose sugar, Bases: TAGC

RNA: single stranded, ribose sugar, Bases: UAGC

Question 8

Site of transcription

Answer 8

Nucleus

Question 9

Enzyme responsible for transcription

Answer 9

RNA polymerase

Question 10

Steps in transcription

Answer 10

• RNA polymerase unwinds the DNA.
• Hydrogen bonds between the bases break.
• RNA nucleotides bond to DNA nucleotides by complementary base pairing.
• RNA polymerase forms the sugar-phosphate backbone of mRNA.
• Hydrogen bonds between mRNA and DNA break, primary transcript is ready for splicing.
• DNA double helix reforms.

Question 11

How can one gene code for several proteins

Answer 11

Alternative RNA splicing

Question 12

What process creates mature mRNA from the primary transcript

Answer 12

RNA splicing

Question 13

Define intron and exon

Answer 13

Intron: Non-coding region
Exon: Coding region

Question 14

Steps involved in translation

Answer 14

• Ribosome binds to mRNA
• Start codon on mRNA is recognised by anticodon on tRNA
• tRNA carries specific amino acid
• Next codon on mRNA recognised by tRNA anticodon and next amino acid added
• Peptide bonds form between amino acids
• Translation continues until STOP codon is recognised