


DNA
o
o
o
The molecule of life
Blueprint for all life
Codes for amino acids which make up proteins
 Structure for an organism
o DNA=deoxyribonucleic acid
 Stores genetic info
 Compared to a ladder
 Each step is a pair of the following four chemicals
 Guanine (G)
 Cytosine (C)
 Adenine (A)
 Thiamine (T)
 A-T
 C-G
o Different species have different amounts of chromosomes
 Dogs have 78
 Cats have 38
 Humans have 46
 Organized into pairs
o Chromosomes
 Packages of DNA
 Located in the nucleus of cells
o Genes
 Responsible for sharing your DNA
 One gene is an uninterrupted piece of DNA
Patterns of inheritance
o Purebred vs. hybrid
 Purebred
 Organism that has ancestors all with the same form of a trait
 Two dominate or recessive alleles (BB or bb)
 Hybrid
 organism that was produced by crossing two individuals purebred for
different forms of a trait
 BB x bb = Bb
o Incomplete dominance
 CC x BB = BC
Cell division
o You must double all of your DNA before it divides
o Mitosis

o
o
o
Type of cell division that produces two identical daughter cells from one parent
cell
Daughter cells retain the same number and kind of chromosomes as the mother

Meiosis
 Cell division that produces cells with only half the DNA of a normal cell
 Four daughter cells from one parent cell
Somatic cells
 Cells that replicate by mitosis
Gametes
 Sex cells
 Products of meiosis
Homework


DNA materials for Wednesday
Investigation page 44