Cellular Reproduction

Chromosomes Contain genetic information – DNA DNA is arranged in segments called genes Determine characteristics, or traits Humans have 46 chromosomes in their cells – 23 from each parent

Chromosomes Exist as chromatin prior to cell division - relaxed form of DNA in the cell’s nucleus

Chromosomes Centromere: at the center of the chromosome where the sister chromatids attach Sister chromatids: Each half of the X, contains identical copies of DNA

Chromosomes

HUMAN CHROMOSOMES

The Cell Cycle Cell division prevents the cell from becoming too large Cells have an optimal size, if a cell is too large, it will have difficulty supplying nutrients and expelling waste. Cell division is also how the cell reproduces, replaces other cells, grows, and heals Cells reproduce by growing and dividing during the CELL CYCLE 3 Main Stages: Interphase, Mitosis, Cytokinesis

The Cell Cycle Interphase is the stage during which the cell grows, carries out cellular functions, and. Replicates. Three parts: G1, S, G2 Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide. Cytokinesis is the method by which a cell’s cytoplasm divides, creating a new cell.

The Cell Cycle

Interphase G1: The cell is growing, carrying out normal cell functions, and preparing to replicate DNA. Occurs immediately after the cell divides. S: (Synthesis)The cell copies its DNA in preparation for cell division. G2: The cell prepares for the division of its nucleus.

Mitosis Mitosis: Process that divides the nucleus of one cell into two nuclei Purpose is to create two daughter cells with identical genetic information Each daughter cell receives the exact same # and type of chromosomes, it’s like photocopying the cell!

Mitosis Prophase Beginning phase, longest phase Chromatin tightens into X-shaped chromosomes Nuclear envelope disappears Centrioles migrate to poles Spindle fibers form

Mitosis Metaphase Changing phase, one of the shortest stages Chromosomes are pulled to center of cell and lined up Ensures there are accurate copies of the chromosomes

Mitosis Anaphase Anew phase The spindle fibers pull chromosomes apart into two identical chromatids The chromatids are pulled to opposite ends of the cell

Mitosis Telophase Ending phase Chromatids reach the poles of the cell and begin to unwind Two new nuclear membranes begin to form Nuclei reappear

Cytokinesis After mitosis, the cell undergoes cytokinesis This divides the cytoplasm The cytoplasm is pinched (the furrow) Creates two new cells

Animal Cell - Mitosis Interphase                                                              Prophase                                                              Metaphase                                                              Anaphase                                                              Telophase                                                             

Plant Cell - Mitosis Interphase                                                              Prophase                                                              Metaphase                                                              Anaphase                                                              Telophase                                                             

The Cell Cycle

I Pray More At The Church! The Cell Cycle Interphase Prophase Metaphase Anaphase Telophase Cytokinesis I Pray More At The Church!

9.3 Cell Cycle Regulation In a normal cell cycle, different cyclin/CDK (proteins) combinations signal activities including DNA replication, protein synthesis, and nuclear division throughout the cell cycle.

Cell Cycle Regulation These checkpoints monitor the cycle and can stop it if something goes wrong. CANCER: the uncontrolled growth and division of cells Cancer cell can kill an organism by crowding out normal cells, resulting in the loss of tissue function

Cell Cycle Regulation The changes that occur in the regulation of cell growth and division of cancer cells are due to mutations. Inherited Carcinogens Radiation

Cell Cycle Regulation Apoptosis: Programmed cell death Cells going through this apoptosis actually shrink and shrivel in a controlled process

Cell Cycle Regulation

Stem Cells Unspecialized (blank) cells that can develop into specialized cells when under the right conditions

9.3 Stem Cells Embryonic Stem Cells: After fertilization, the resulting mass of cells divides repeatedly until there are about 100–150 cells. These cells have not become specialized. Adult Stem Cells: Found in various tissues in the body and might be used to maintain and repair the same kind of tissue. Less controversial because the adult stem cells can be obtained with the consent of their donor