1. DNA

2. What is DNA? Contains all genetic information of the entire organism
Located in the nucleus of all cells (with a few exceptions!)
mature red blood cells have no nucleus
sex cells have half the amount of genetic information (haploid)
A “full set” in humans is 46 chromosomes
Made up of 23 pairs (diploid)

3. But not in all animals! Organism # of Chromosome Pairs Human 23
Drosophila (fruit fly) 4
E.coli (bacteria)
Mosquito 3
Fly
Frog 18
Cat 19
Chimpanzee 24
Horse 32
Dog 39
Onion 8
Peanut 12

4. DNA spends most of its time in a long string called chromatin
During cell division, chromatin coils up tightly to form chromosomes

6. the section of DNA that codes for a protein is called a gene

7. DNA -> RNA -> Protein (made of amino acid)

8. DNA Structure DNA is made of nucleotides composed of 3 parts DNA:
5 carbon sugar: deoxyribose
one nitrogenous base (4 possible options!)
phosphate group
DNA:
Deoxyribo-
Nucleic acid

9. There are two types of nitrogenous bases:
1. Purines
-Adenine (A) and Guanine (G)
-2 fused rings
2. Pyrimidines
-Cytosine (C) and Thymine (T)
-only one ring
Adenine ALWAYS bonds with thymine
Guanine ALWAYS bonds with cytosine
-this is called complimentary base pairing

11. DNA looks like a twisted ladder
This arrangement is called a double helix

12. Alternating sugar and phosphates make up the backbone (the “rails” of the ladder)
Bases make up the “rungs” and are held together by weak hydrogen bonds