Overview of Genetics Genes make us who we are!

Genes are composed of DNA Genes are composed of DNA. DNA provides the instructions for cells to make amino acids which are the building blocks of proteins. These proteins control everything from what we look like, to our personality, to our health.

Deoxyribonucleic Acid (DNA) DNA is made up of a base (adenine, guanine, cytosine, and thymine), a sugar, and a phosphate group bonded together- this is referred to as a nucleotide

Nucleotides are linked together by bonds to form a DNA chain

Double-stranded DNA is simply two chains of single- stranded DNA, positioned so their "bases" can interact with each other Guanine always pairs with cytosine Adenine always pairs with thymine The two strands run in opposite directions or are “antiparallel”

These strands form a 3D double helix Phosphate group is the backbone, sugar connects phosphate group to the base, base pairs of opposite strands are bonded together.

Ribonucleic Acid (RNA) Single stranded polymer of ribonucleotides Ribonucleotides components: Phosphate Sugar: Ribose Base: Guanine G Adenine A Uracil U Cytosine C Uses information on DNA to construct proteins

Human Genome Contains about 24,000 protein encoding genes Only a small % of DNA encodes for proteins-the rest of the DNA sequence has unknown functions or is believed to turn protein encoding genes on or off.

Alleles Variations of protein encoding genes caused by mutation Mutations can cause disease, variation, benefits, or no visible effect at all.

Chromosomes Composed of DNA wrapped around proteins Humans have 23 pairs chromosomes 22 pairs are autosomes (same for male and females) The 23rd pair (X and Y) are sex chromosomes. Females have XX chromosomes. Males have XY chromosomes. Karyotypes show chromosomes ordered from largest to smallest.

G Genetics 101: Part 1 hyperlink Genetics 101: Part 2 hyperlink