Biology 121-224. January 31 to February 3 , rd
The Cell Cycle and Mitosis
Reading: Ch. 11: 234-243, 248-251
1) Determine whether eukaryotic cells are haploid, diploid or polyploid.
2) Illustrate with simple diagrams how cells produce daughter cells during
3) Describe the events that occur during the cell cycle, how the cycle is
regulated and how errors in regulation can lead to cancer.
A) Cell Division (mitosis, meiosis)
Self reproduction – the “instructions” in our model are coded in the DNAin the form of
chromosomes and the “object” that is being replicated is the cell.
Chromosomes and DNA Apair of chromosomes
- Double helix (spiral)
- Sugar phosphate on the side
- Adenine Thymine, Guanine Cytosine
- Base pair
- Length of chromosomes in units of base pairs (BP)
- Gene is a sequence of BP, a sequence of DNA
- Picture of all the chromosomes “ genome”
- Human genomes, 23 different chromosomes 46 total chromosomes.
• Division of the genetic material in the nucleus that produces daughter cells
Genetically identical to the parent cell. • Mitosis is the basis of asexual reproduction and is involved only in the production
of Somatic (body) cells. – not the reproductive
• Division of the genetic material in the nucleus to produce daughter cells with Half
the amount of hereditary material found in the parent cell.
• Involved only in the production of Gametes (eggs and sperm);
it is the basis of sexual reproduction and genetic inheritance.
Salamander has the most number of chromosomes of any organisms
B) The Cell Cycle
What is cancer?
Cancer cells differ from normal cells:
Divide when they should not divide
Invade surrounding tissue
Move to other locations in the body
Out of control cell division
Phases of the Cell Cycle
• Mitotic (M) phase
- Division of the cells (PMAT)+ C
• Interphase Daughter cells
First Gap Phase (G1) - Organelles replicate and additional cytoplasm
- Chromosomes duplicate (chromatid)
- Same number of chromosomes but more DN