Mitosis How do your cells divide? Chapter 10

Why Do Cells Divide? Surface area Damaged cells Sex cells

Cell Reproduction is either sexual or asexual

Asexual Reproduction (one parent)  Binary Fission-  Budding  Vegetative Propagation  Regeneration

Advantages of Asexual Reproduction Speed Desirable Characteristics Replacement

Division of the Cell A. Cell division – the process by which a cell divides into two new daughter cells. B. Before cell division occurs, the cell replicates all it’s DNA giving each cell its own complete set of genetic information. C. Each daughter cell also has an increased surface area to volume ratio. Division of the Cell 2. Cell division – the process by which a cell divides into two new daughter cells. 3. Before cell division occurs, the cell replicates all it’s DNA giving each cell its own complete set of genetic information.

Chromosomes 4. The genetic information that is passed from one generation of cells to the next is carried by chromosomes. 5. Chromosomes are made of DNA and protein.

C. At the beginning of cell division, each chromosome is replicated. D. Each replicated chromosome consists of two chromatids attached at the centromere. 1. chromatid – one of two identical sister parts of a duplicated chromosome. 2. centromere – the area where the two chromatids are attached.

II. The Cell Cycle is made up of: A. Interphase – (G1, S, G2) the period of growth between cell divisions. B. Cell division

III. Events of the Cell Cycle (see Figure 10-4) A. Interphase is divided into three phases: 1. G1 phase – period of activity in which cells do most of their growing.

2. S phase – chromosomes are replicated and the synthesis of DNA molecules take place. 3. G2 phase (shortest of the three) – many of the organelles and molecules required for cell division is produced..

B. When the events of G2 phase are completed, the cell enters M phase where mitosis and cytokinesis take place

Eukaryote cell division occurs in two stages: a. Mitosis – division of the cell nucleus. b.Cytokinesis – division of the cytoplasm.

The Cell Cycle

A Cell’s Life Cycle When does a cell divide? M G1G1 S G2G2 C G1G1 Most of a cell’s life cycle is spent in Interphase when it performs normal life functions

6. After interphase, the cell enters mitosis which is the division of the nucleus.

Parent Cell DNA condenses into chromosomes; Chromosomes attach to the spindle fibers Chromosomes line up on the equator Prophase Metaphase MITOSIS

Telophase DNA uncoils; 2 nuclei form Anaphase Chromosomes separate and are pulled to opposite ends

Cytokinesis- division of the cytoplasm  Cleavage (indention in cell membrane) or cell plate formation occurs.  Cell divides. Animal Cell Plant Cell

Mitosis Animation

Overview of the Cell Cycle

It’s all about the chromosomes! 10. There are 46 in human body cells (23 pair) –The number of chromosomes remain constant during Mitosis

Which Cells Go Through Mitosis? Grow Repair Work Cells which help the body The cells are called autosomes

12. What happens if cell division gets out of control ?  CANCER  The body doesn’t respond normally to the body’s control mechanisms

“Checkpoints” Cell Cycle Regulators 13. Cyclin – proteins that regulate the timing of the cell cycle in eukaryotic cells. * Two types of regulatory proteins: internal regulators and external regulators.

1. Internal regulators – allow the cell cycle to proceed only when certain processes have happened inside the cell. 2. External regulators – direct cells to speed up or slow down the cell cycle. example – growth regulators

Bone Cancer X-ray Ovarian Cancer Cell Dividing

14. Causes of cancer include smoking, tobacco, radiation exposure, and viral infection.

Skin Cancer

Mitosis Review 1. Is the beginning parent cell diploid or haploid ? Diploid 2. Are the daughter cells diploid or haploid (2n or n)? Diploid

More Mitosis Review 3. How many daughter cells are produced? 2 4. Are the resulting daughter cells different from the parent cell? NO

More Mitosis Review 5. Are the resulting daughter cells different from each other? NO  How many chromosomes are in a human parent cell? 46 Diploid or Haploid? Diploid

 7. How many chromosomes are in a human daughter cell?46  Diploid or Haploid?  Diploid

More Mitosis Review 7.What types of cells are produced by mitosis? Autosomes (body cells) 8. Why (when) does a cell go through mitosis? Growth, repair, make more cells

10. What is the name of the process? Mitosis 11. What are the names of the phases? A. prophase B. metaphase C. anaphase D. telophase

12. The cell labeled I is in what phase of the cell cycle? interphase 13. The nucleus is going through process of mitosis and division of cytoplasm known as cytokinesis.