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Contents 1 Protein Synthesis 2 Triplet Code 3 Genes and Genomes 4 Comments

Protein Synthesis

DNA in the nucleus codes for the joining of amino acids in a certain order to produce specific proteins.

The sequence of amino acids determines the type of protein that is made.

	DNA	RNA
Sugar	deoxyribose	ribose
Bases	adenine, cytosine, guanine, thymine	adenine, cytosine, guanine, uracil
Structure	double stranded	single stranded
Found in	nucleus	nuclei, cytoplasm, ribosomes

In RNA uracil is found instead of thymine.

Complementary bases: A and T (or A and U), C and G.

Triplet Code

There are about 20 different amino acids.

Three bases are needed to code for an amino acid (triplet code).

These three bases together are known as a codon.

The sequence of bases is always read in one particular direction.

Each amino acid has a different codon:

• CAA stands for the amino acid valine

• TTT stands for the amino acid lysine

• CCC stands for the amino acid leucine

• GGC stands for the amino acid glycine

There are also three codes for stopping the formation of an amino acid chain.

These are UAA, UAC, or UGA.

Genes and Genomes

A length of DNA which codes for the whole of one protein is called a gene.

The total set of genes in a cell is called the genome.

Comments