Chapter 10: Cell Cycle Notes

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

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.

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.

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

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 (G 1,S & G 2 phases) –Step (2.) Cell Division –Mitosis-division of nucleus –Cytokinesis- division of cytoplasm

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

G1 phase initial growth phase of the cell. The cell grows and carries out its routine functions. The cell grows and 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. Other cells get stuck in G1 of interphase until cell division is needed for growth or repair.

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

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

G1 S G2

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

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. It is the beginning of cellular division.(PMAT)- –Prophase, Metaphase, Anaphase, & Telophase Mitosis Animation Simple

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.

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 Slide # 5

Prophase: 1 st Phase Prophase: 1 st 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

Metaphase 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

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

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

Cytokinesis 1. Cytokinesis is division of the cytoplasm 2. Distributes the organelles a.In animal cells, the cell membrane pinches in two. b.In plant cells, a cell plate forms across the middle.

What Phase Of the Cell Cycle Is It? ABC D EF Anaphase Interphase CytokinesisTelophase ProphaseMetaphase

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. 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.

BRAIN TUMOR BREAST TUMOR PANCREATIC CANCER ORAL CANCER

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.