Chapter 10: Cell Cycle Notes

1. Chapter 10: Cell Cycle Notes

2. Why Divide? The cell theory states that: All cells come from other livingcells. • Cells divide for the survival of the individual organism • Cells divide for the survival of the species (group of similar organisms)

3. Cells divide for the survival of the individual organism Cell division is used for growth, development, maintenance, and repair of the organism. This is carried out by: • Mitosis- division of body cells to make more of the same kind of cell. • The parent cell is the original cell inside the organism that will divide. • The daughter cells are the two identical cells created when the parent cell divides.

4. Cells divide for the survival of the species To reproduce more organisms that look similar to their parents: • Sexual reproduction-two separate organisms produce egg and sperm that must combine or fuse together to produce offspring. • Meiosis process of making egg cells and sperm cells. • Fertilization the fusion of egg and sperm to produce a new organism.

5. Cells divide for the survival of the species To reproduce more organisms that look similar to their parents: • Asexual reproduction- offspring are produced by only one individual organism. • Spores are produced by mold and other fungi that grow all by themselves into more fungi. • Binary fission is the process of a bacterium splitting in two new bacteria

6. Cell Cycle • Cell Cycle- is defined as the life of a cell from the beginning of one interphase to the beginning of the next interphase. (with cell division in between) • Step (1.) Interphase (G1,S & G2 phases) • Step (2.)Cell Division • Mitosis-division of nucleus • Cytokinesis- division of cytoplasm

7. Cell Cycle: Interphase Step 1: Interphase – is the growth and development phase of the cell cycle. Three parts: (1.) Growth One or G1 phase (2.) Synthesis or S phase (make DNA) (3.) Growth Two or G2 phase

8. G1 phase • initial growth phase of the cell. • The cell growsand carries out its routine functions. • This is the longest phase of interphase. • Many cells stop growing and get stuck in this phase for the entire life of the organism (Ex. Nerve cells). • Other cells get stuck in G1 of interphase until cell division is needed for growth or repair.

9. S phase (synthesis) • is when DNA replication occurs. • After DNA replication the cell has two complete copies of its DNA. • At this point, the cell is committed to dividing.

10. G2 phase • the cell continues to grow and the final preparations for cell division are made.

11. G2 G1 S

12. Cell Cycle: Cell Division • Step 2: Cell Division: -the creation of two daughter cells from one parent cell. *Each daughter cell will have the same number of chromosomes as the parent cell.* Two Parts of Cell division: Mitosis and Cytokinesis

13. Cell Division: Mitosis • Mitosis – “division of the nucleus”. It is a synchronized set of events that will separate chromosomes, so that the two nuclei formed will be identical. • It is the beginning of cellular division. • (PMAT)- • Prophase, Metaphase, Anaphase, & Telophase • Mitosis Animation Simple

14. Cell Division: Cytokinesis • Cytokinesis “division of the cell cytoplasm”. It is the physical separation of the cytoplasm into two new daughter cells. • It is the end of cell division. • New cells pinch off from each other in animal cells. In plants, a cell plate is formed, because plants also have cell walls to form.

15. Slide # 5 Vocabulary 1. Chromosome: coiled DNA structures within the nucleus containing genetic information that is passed on from generation to generation 2.Sister Chromatid: one of two identical “sister” parts of a duplicated chromosome-formed during S phase 3. Centromere (A): chromosome region that joins 2 sister chromatids

16. Prophase: 1st Phase 1. DNA coils & becomes chromosomes 2. Centrioles move to opposite ends of cell 3. Spindle fibers attach to chromosomes 4. Nuclear membrane breaks down

17. Metaphase 1. Spindle fibers push & pull chromosomes until they line up across center of cell 2. Centromere of each chromosome pair is attached to a spindle fiber

18. Anaphase 1. Spindle fibers shorten & paired chromatids separate 2. Spindle fibers pull separated chromosomes to opposite ends of the cell 3. Centromere of each pair divides; now have individual chromosomes

19. Telophase 1. Chromosomes begin to uncoil and decondense 2. Nuclear membrane reforms around each new set of chromosomes

20. Cytokinesis • Cytokinesis is division of the cytoplasm • Distributes the organelles • In animal cells, the cell membrane pinches in two. • In plant cells, a cell plate forms across the middle.

21. What Phase Of the Cell Cycle Is It? A B C Anaphase Telophase Cytokinesis D E F Interphase Metaphase Prophase

22. CANCER • is the caused by uncontrolled cellular division. • Typically, most cells don’t divide unless it is for repair or maintenance. • Cancerous cells keep dividing; crowding out and stealing nutrients from healthy tissue. • Cancer “kills” when a mass of cancer cells called a tumor interferes with the functions of major organs.

23. BRAIN TUMOR BREAST TUMOR ORAL CANCER PANCREATIC CANCER

24. The picture on the left shows a healthy right lung, and a small discolored left lung. This indicates the presence of tumors, as seen in the picture on the right.