IB Biology Topic D1.2.8 Features of the Genetic Code Revision Notes (SL/HL)

IB Biology Topic D1.2.8 Features of the Genetic Code Revision Notes (SL/HL) | RevisionDojo

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The genetic code is a triplet, degenerate, and near-universal set of rules

The genetic code is the set of rules by which the base sequence in DNA is translated into a sequence of amino acids.
It has three defining features: it is a triplet code, it is degenerate, and it is near-universal.

Definition

Degenerate

Multiple codons code for the same amino acid, reducing the impact of mutations.

Definition

Universal

Nearly all organisms use the same code, allowing for genetic engineering and biotechnology advances.

Codons are read in triplets because pairs cannot cover 20 amino acids

DNA is built from four bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
Proteins, however, are built from 20 different amino acids.
The number of bases read per amino acid must therefore generate at least 20 distinct combinations.
1. One base per amino acid gives only $4^1 = 4$ combinations, far too few.
2. Two bases per amino acid give $4^2 = 16$ combinations, still short of 20.

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Tip

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Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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The genetic code is a triplet, degenerate, and near-universal set of rules

The genetic code is the set of rules by which the base sequence in DNA is translated into a sequence of amino acids.
It has three defining features: it is a triplet code, it is degenerate, and it is near-universal.

Definition

Degenerate

Multiple codons code for the same amino acid, reducing the impact of mutations.

Definition

Universal

Nearly all organisms use the same code, allowing for genetic engineering and biotechnology advances.

Codons are read in triplets because pairs cannot cover 20 amino acids

DNA is built from four bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
Proteins, however, are built from 20 different amino acids.
The number of bases read per amino acid must therefore generate at least 20 distinct combinations.
1. One base per amino acid gives only $4^1 = 4$ combinations, far too few.
2. Two bases per amino acid give $4^2 = 16$ combinations, still short of 20.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic D1.2.8: Features of the Genetic Code Notes

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

The genetic code is a triplet, degenerate, and near-universal set of rules

Codons are read in triplets because pairs cannot cover 20 amino acids

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

The genetic code is a triplet, degenerate, and near-universal set of rules

Codons are read in triplets because pairs cannot cover 20 amino acids

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account