DNA, genes & protein synthesis

Question 1

Describe what a gene is.

Answer 1

• base seq of DNA
• codes for a.a. seq
• of a polypeptide/ functional RNA

Question 2

It is possible that an amino acid sequence codes for many different amino acids or many copies of the same amino acid.
Explain how this can happen.

Answer 2

• some a.a. have up to 6 codes (degenerate?)
• vs others only have 1

Question 3

Codon vs anticodon

Answer 3

• both triplet of bases
• codon- on mRNA, codes for a.a.
• anticodon- on tRNA, complementary to codon

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Question 4

Explain an advantage of mRNA being broken down relatively quickly.

Answer 4

• mRNA produced to manufacture protein (eg. enzyme)
• produce protein continuously = wasteful when only needed periodically
• ∴ breaks down once used –> produced again only when needed

Question 5

State which other enzyme (other than RNA polymerase) is involved in transcription and describe its role.

Answer 5

DNA helicase
- break H bonds betw. bases on specific region of DNA molecule
- separates 2 strands
- expose bases