Chapter 9 MITOSIS Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Copyright © The McGraw-Hill Companies, Inc Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Read pg 154 “science focus” on the G1 checkpoint Answer on paper with AP questions: What is the G0 stage? Is it permanent? What is RB and explain it’s function? What conditions could prevent a cell form dividing? What is the function of the p53 protein?

checkpoints Describe what each checkpoint is for: a. G1checkpoint b. G2 checkpoint c. M checkpoint

9.1 The Cell Cycle **Orderly set of steps between eukaryotic cell divisions Why do Cells Divide? - Growth - Reproduction    (single celled organisms) - Repair

Cell Cycle: Control of the Cell Cycle G2 – Gap 2 Cell prepares for mitosis S – synthesis DNA is replicated G1 – Gap 1 Cell growth and performs normal functions Control of the Cell Cycle  G1 Checkpoint - Check to see if DNA is damaged G2 Checkpoint - Check to see if DNA is replicated properly M Checkpoint - spindle assembly checkpoint, check for alignment of chromosomes 

Apoptosis - programmed cell death, if any of the checks fail Control of the Cell Cycle  G1 Checkpoint - Check to see if DNA is damaged G2 Checkpoint - Check to see if DNA is replicated properly M Checkpoint - spindle assembly checkpoint, check for alignment of chromosomes  Apoptosis - programmed cell death, if any of the checks fail

Control of Cell Cycle Growth Factors: signal cell growth Cyclin: family of internal signaling proteins that increase or decrease the cell cycle (feedback/ homeostasis) P53: stop cell at G1 if there is damage RB: protein responsible for interpreting growth signals and available nutrients Somatic Cells: body cells Apoptosis: programed cell death

Cyclin: family of internal signaling proteins that increase Cyclin: family of internal signaling proteins that increase or decrease the cell cycle Cyclin D: increase then decrease over one full cycle Cyclin E: triggers DNA replication (S) Cyclin A: triggers G2 Cyclin B: triggers mitosis

What would be the affect of no cyclin E being produced? What happens if there is a mutation during S? What would happen if no cyclin D was produced?

 9.2 Mitosis & Cytokinesis  Mitosis - The division of the nucleus that results in identical complete copies of chromosmes packaged into two new nuclei Cytokinesis - The division of the cytoplasm that results in two daughter cells

Interphase • Prophase • Metaphase • Anaphase • Telophase IPMAT

Interphase:  ”Resting”, normal cell processes Prophase: Chromosomes visible, spindle forms as centrioles move to opposite poles Metaphase:  Chromosomes line up along equator Anaphase:  Chromatids separate into individual chromosomes Telophase:  Nuclear membrane re-forms on each side, cytokinesis begins = split cytoplasm

**In plant cells, cytokinesis begins when a new cell wall forms between the two new cells. **In animal cells, the two new cells pinch and pull apart

Mitosis produces 2 daughter cells The two daughter cells contain the exact same number of chromosomes as the original parent cell Daughter cells are DIPLOID= 2n= complete set of chromosomes

9.3 The Cell Cycle and Cancer neoplasm: abnormal growth of cells benign: non-cancerous malignant: cancerous Cancer: cellular growth disorder that results from the mutation of genes that regulate the cell cycle Cancer cells lack differentiation have abnormal nuclei Mutation cause oncogenes: cancer genes that keep the cell replicating Inactivate tumor suppressors (p53 and RB) form tumors undergo metastasis & angiogenesis 

HeLa Cells Article on Henrietta Lacks A HeLa cell (also Hela or hela cell) is a cell type in an immortal cell line used in scientific research. It is the oldest and most commonly used human cell line. The line was derived from cervical cancer cells taken from Henrietta Lacks, a patient who eventually died of her cancer on October 4, 1951.

Telomeres Shorten as the chromosome replicates At a certain length, tigers apoptosis Some cancer cause them to remain at a constant length

Binary Fission: asexual reproduction by prokaryotes

- stem cells may replicate many times, or proliferate. unspecialized cells capable of renewing themselves through cell division - stem cells may replicate many times, or proliferate. They have the potential to develop into many different cell types in the body during early life and growth.

Major types of stem cells Embryonic Stem Cells Pluripotent : cell can develop into all cell types “Immortal”: can self-renew indefinitely Plentiful (easy to find) Adult Stem Cells Multipotent: cell can develop into a few cell types but not all Located in few organs or may be unidentified Hard to find

QOD: mitosis How many chromosomes do humans have? What is the purpose of mitosis? What do single celled organism use mitosis for and what is it called? Describe what each checkpoint is for: a. G1checkpoint b. G2 checkpoint c. M checkpoint

Name the phases starting at the top.

Name the phase Identify X Identify Y

5. Name the phase

6. Name the phase

10. In humans, each cell (except sex cells) has how many chromosomes 11.  After mitosis, how many daughter cells are produced?  _______ 12.  After mitosis (in a human cell), each daughter cell has how many chromosomes? ___ 13.  How many phases are in MITOSIS? ___________ 14.  Which phase of the cell cycle is the longest?  _________ 15.  During which phase does cytokinesis begin?  __________