DNA Deoxyribose Nucleic Acid DNA is made up

DNA (Deoxyribose Nucleic Acid) ØDNA is made up of a sugar, phosphate, and nitrogen base. ØThere are 4 nitrogen bases ØAdenine, Thymine, Cytosine, Guanine (A, T, C, G) ØA only pairs with T ØG only pairs with C ØDNA looks like a ladder. ØThe sides of DNA ladder are alternating sugar and phosphate. ØThe “rungs” of the DNA ladder are made up of two nitrogen bases. ØThe nitrogen bases are attached to the sugar ØEither A & T or C & G

Chromosomes • DNA is wrapped around proteins, which help compact the DNA, into structures called chromosomes. • Chromosomes are made up of DNA.

Human Chromosomes! • Body cells have 46 chromosomes, or 23 pairs. • Sex cells have 23 chromosomes.

Genes • Genes are segments of DNA that code for specific proteins. - Different genes are activated in different cells, creating the specific proteins that give a particular cell type its character.

Karyotype • A picture of a cell’s chromosomes. • Chromsomes #1 -22 are paired. • In each pair one chromosome comes from mother and one from the father. • The sex chromosomes are labeled X or Y. – Females have two X’s (XX= females). – Males have an X and a Y (XY= males). From “MOM” From “DAD” MALE XY

Genetic Counselor • Looks at the DNA of individuals, as well as unborn babies, to determine the likelihood of having a specific genetic disorder.