[Unit 8.1] | Gene & The Genetic Code

Question 1

What is a gene?

Answer 1

• A base sequence from DNA that holds the coded information for making polypeptides & RNA.

Question 2

What is a locus?

Answer 2

A gene located at a particular position on a DNA molecule.

Question 3

How many amino acids regularly occur in proteins?

Answer 3

20

Question 4

Why are there 64 possible triplet combinations?

Answer 4

4³ = 64
(4 possibilities ^ 3 bases)

Question 5

What does the existence of 64 triplet codes mean?

Answer 5

Some different combinations may code for the same amino acid.

Question 6

What makes the genetic code ‘degenerate’?

Answer 6

Most amino acids are coded for by more than one triplet.

Question 7

What does non-overlapping mean?

Answer 7

• Each base in a sequence is read once.

• Triplets: 123 456
vs
• Triplets: 123 234 345 456 (Overlapping)

Question 8

What does universal mean?

Answer 8

• All organisms share the same genetic code. (Indirect evidence for evolution)

Question 9

What are introns and exons?

Answer 9

• Intron: Non-coding sequence.

• Exon: Coding sequence.