DNA`The Molecule of Heredity

D.N.A.

Deoxyribonucleic acid

A Where is DNA found?

1. In nucleus

2. organized into chromosomes

B .Structure of DNA 1. “ladder” with a twist

(Double helix)

The double helix structure of DNA was discovered by Watson and Crick in 1953.

The structure was discovered using an X-Ray crystallograph photo of DNA taken by Rosalind Franklin in 1952

2. “sides” of ladder made of alternating

-deoxyribose sugar molecules

-And phosphate groups

A

T

C

G C

A

T

G

3) The “rungs” of the ladder are one of four nitrogenous bases:

A - adenine

G - guanine

C - cytosine

T - thymineDraw this!!!

4) The bases are held together by weak hydrogen bonds

A

C

T

G

a) . Two hydrogen bonds hold adenine and thymine together

b). Three hydrogen bonds hold cytosine and guanine together

Draw this!!

5. Nucleotide

• a) Three piece unit

–Deoxyribose sugar

–Phosphate group

–Nitrogenous base

C. DNA contains genetic information.

1. The information is stored in the nitrogenous bases AATTCGAT

a) The order of the bases determine the type of information

– ATTCG

– ATCCG

2. This information is passed from parent to offspring

3.This information ultimately codes for amino acids which make different proteins

Function of DNA

Stores Genetic Information Controls the making of proteins