BIOL 120 Genetics-Cell Cycle, Mitosis, Cancer
• Somatic Cells
- body cells
- for growth/repair
- makes identical copies
• Germ Cells
- sex cells
- to make gametes (egg/sperm)
- makes unique cells
- ½ chromosomes #
* one of each type of chromosome
Overview of Cell Division (somatic Cell)
1.Replication: DNA is duplicated
2.Mitosis: The two quantities of DNA are moved to opposite sides of the parent cell
3. Cytokinesis: The parent cell splits into two daughter cells
The Cell Cycle
1. Interphase: DNA is copied
2. Mitosis: DNA split equally into two daughter cells
3. Cytokinesis: Parent Cell is cleaved in half
During Interphase, the chromosomes are uncondensed or usable.
During M Phase (Mitosis), the chromosomes are condensed or movable.
Chromosomes and DNA Replication
Chromatin – a mass of genetic material composed of DNA and proteins that condense
to form chromosomes.
Chromatid – one of the two identical copies of DNA making up a duplicated
chromosome, which are joined at their centromeres.
DNA Replication Precedes cell division.
A) The double-stranded DNA molecule is copied – first by splitting the molecule in
half up the middle of the helix. New nucleotides are added to each side of the original
parent molecule.Results in the production of 2 identical daughter DNA molecules from 1
parent molecule. Each daughter DNA molecule contains half of the parental DNA and
half of the newly synthesized DNA.
B) The DNA polymerase enzyme m