You and Your Genes Revision Lesson 1. What are Genes?. All living organisms are made of cells Most cells have a nucleus In the nucleus are chromosomes, made from DNA. To write: DNA makes up chromosomes in the nucleus of cells. Chromosomes contain thousands of genes
DNA makes up chromosomes in the nucleus of cells.
Sections of chromosomes are called genes, which control cells and code for proteins.
Most human cells have 46 chromosomes (23 pairs – one from each parent).
Different versions of genes are called alleles.
Our mix of alleles determines what we are like.
Most characteristics are due to a number of genes. Some are due to only one gene, and some are affected by environment.