IB Biology SL D1.2.8 Genetic Code Features Questions

In IB Biology SL D1.2.8, each mRNA codon is a triplet that specifies an amino acid or a start/stop signal. The genetic code is degenerate and almost universal, with a few exceptions.

Exam points

Read nucleotide sequences in triplets and relate each mRNA codon to an amino acid or a start/stop signal.
Explain degeneracy by identifying different codons for the same amino acid and recognizing why some base changes leave the amino-acid sequence unchanged.
Recognize that the genetic code is almost universal and interpret rare exceptions.

[Maximum number: 2]

A short base sequence of mRNA and a table of the genetic code are shown below.
Sequence of mRNA
AUGAGCCGAAGGUAGCUG
Table of the genetic code

Table for Question IB Biology SL D1.2.8 Genetic Code Features Questions question 1 — IB Biology SL

(a)

Outline the function of codons.

[ 1 ]

(b)

Suggest a hypothesis that accounts for the slightly different meaning of some codons in a very limited number of organisms.

[ 1 ]

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IB Biology SL D1.2.8 Genetic Code Features Questions question 1

Question (a)

Question (b)