1. Cell Cycle & Checkpoints
Lecture 1

2. Eukaryotic organisms
Heritable information is passed to the next generation via processes that include cell cycle and mitosis or meiosis plus fertilization

3. Cell Reproduction Cell division (MITOSIS)
process that forms new cells from one cell
results in two cells that are identical to the original, parent cell.

4. Importance of Cell Reproduction
Growth (increase in size)
Repair (replace dead or damaged cells)
Asexual reproduction

5. Cell Cycle Sequence of growth and division of a cell
Growth period= Interphase
Nuclear Division= mitosis

8. Interphase Cell grows in size Carries on metabolism
Chromosomes duplicate (synthesis of DNA)
Preparation for mitosis (actual division into 2 identical cells)

9. INTERPHASE = G1, S, G2
G2- Gap 2 Grow Produce molecules & organelles needed for cell division
MITOSIS
G1- Gap 1 Grow by producing proteins & organelles
G0- Cell leaves cycle
and stops dividing Most body cells in this phase
S- Synthesis
DNA replication
Some can return to cycle with signal (external or internal signals) (Ex; Liver cells respond to injury) Some never divide again (Ex: Mature nerve, muscle cells)

15. Cyclin-dependent kinases (Cdk’s) are present all the time but inactive unless combined with cyclins
Enzymes that work by adding a
phosphate group
to other molecules
Presence of MPF (mitosis promoting factor) triggers passage past G1 & G 2 checkpoints

16. Cyclin levels
change throughout
cell cycle
Fluctuating levels
of different
Cyclin-Cdk complexes seem to control
all stages of
cell cycle

17. Cyclin & Cyclin Dependent Kinases
Conserved through evolution
Genes are same across Eukaryotes