Recap

Genetics

Gene

Gene

A section of a chromosome. A sequence of nucleotides/base pairs that code for a protein which can lead to a specific phenotype in the organism

Mutation

A rare and random change in the nucleotide sequence of a gene

Allele

A alternative form of a gene due to a change in the DNA sequence

4 bases of DNA

Adenine, Thymine, Guanine, Cytosine

4 bases of RNA

Adenine, Uracil, Guanine, Cytosine

Structure of DNA

Antiparallel double helix

Chromosomes in diploid human cell

46(23 pairs)

Genes in the genome

25,000

Roles of the DNA

Unit of Inheritance, Code

Unit of inheritance

To pass alleles and thus characteristics onto their offspring

Code

Each gene is a code to a single protein

This protein can lead to different phenotypes

DNA molecule

Phosphate group, sugar and base

3 nucleotides are called

Codon

Amount of Codons

64

Amount of amino acids

20

Does a mutation always cause a change

NO because many codons code for the same amino acid