Presentation on theme: "Aim: What are the major changes in the nucleus during cell division?"— Presentation transcript:
Aim: What are the major changes in the nucleus during cell division?
Mitosis in a single celled organism This type of reproduction involves no exchange of genetic material, and is a type of asexual reproduction. This form of asexual reproduction is often called 'fission'
Mitosis in multi-cellular organisms occurs for GrowthRepair
Asexual Reproduction Budding Although capable of sexual reproduction, hydras reproduce most of the year by producing external asexual buds that eventually pinch off at the base and become new individuals. Budding Hydra
Asexual Reproduction in Plants Underground stems rhizomes bulbs corms and tubers
Asexual Reproduction in Plants Bulbs and Tubers
Mitosis also occurs during early embryonic development Fertilized egg Fetus
Cell division involves the process of Mitosis Step 1 (S phase of Cell Cycle) Chromosomes Duplicate Chromosomes make more of themselves
Cell Division Step 3 Metaphase Chromosomes line up in the middle of the cell
Cell Division Step 4 Anaphase Double stranded chromosomes pull away from each other Animal Cell Plant Cell
Step 5 of Cell Division is Cytokinesis Animal CellPlant Cell
Cancer develops due to the loss of growth control in cells during cell division. Stages of tumor development A B Hyperplasia C Dysplasia D in situ cancer malignant
Aim: What controls the cell cycle?
Readings on Enzymes You will read one article from the folder What is its function? How can cancer develop when this regulation is disrupted?
Ras Proteins Ras protein initiates the cell cycle by stimulating the cell cycle into the S phase and then it stops and waits for another signal to continue A mutation in the ras gene causes the cell to keep the cell cycle running with no checks and balances
P53 Tumor Supressor Binds to DNA and prevents replication More than half of human cancers involve mutations in the P53 protein
Nibrin and ATM Repairs chromosomal damages before Mitosis takes place A mutation in this protein allows the cell to move onto mitosis with the damaged chromosomes
MAD 1 The spindle checkpoint prevents anaphase from occurring until chromosomes have attached to the spindle fibers. Mutation of this protein causes abnormal chromosome numbers in cancer cells.
Some forms of chemotherapy prevent spindle formation.