LECTURE 4
GENETICS
I.
A.
1.
a.
B.
1. the first to demonstrate that heredity followed specific laws of inheritance.
2.
3. discovered that when true breeding plants that have different attributes
of the same variable are crossed, a 3:1 ratio between expressed attribute forms
will result.
C.
1. Law of segregation: units controlling the expression of visible traits come in
pairs and retain their separate identities over the generations.
a.
2.
D.
1.
2.
II. Watson, Crick and Wilkins- In 1953 discovered the Double Helix structure of DNA. Rosalind
Franklin was the first to photograph the DNA strand, which led to the men’s “discovery”.
A. DNA: Deoxyribonucleic Acid: double stranded molecule found in a cell that contains
the genetic information used for controlling the cells function.
B.
1.
2.
1
3.
a.
b. Adenine bonds with Thymine, Guanine bonds with Cytosine.
C. Mutation. Ultimate source of variation. Random change in genetic material caused by
mechanical error during the process of DNA synthesis and replication as well as during
division of sex cells.
1.
a.
b.
c.
2.
a. the organism usually dies
2