B1 - You and Your Genes

Genes are sections of very long DNA molecules that make up chromosomes in the nuclei of cells.

Chromosomes are organized structures of DNA and proteins that are found in cells.

DNA carries the genetic information in the body’s cells.

Alleles are the different types of genetic material that code for a specific protein or gene.

The nucleus is a dark structure inside the cell that controls the cell's activities and contains material like DNA.

A recessive allele only shows if the individual has two copies of the recessive allele. For example, the allele for blue eyes is recessive. You need two copies of the allele to have blue eyes.

A dominant allele always shows, even if the individual only has one copy of the allele. For example, the allele for brown eyes is dominant. You only need one copy of the allele to have brown eyes (and two copies will still give you brown eyes).

Cell
Nucleus
DNA
Chromosome
Gene

All women have two X chromosomes. 

**

All men have an X and a Y chromosome.

XY

Proteins are the building blocks of cells. Their are two typesof proteins:

Structural proteins - They are part of things like skin, hair, blood and the cytoplasm in our cells

Functional proteins - Enzymes are proteins that help with digestion by breaking down food molecules.