Cellular Reproduction Section 1 Cellular Growth Section 2

Cellular Reproduction Section 1: Cellular Growth Section 2: Mitosis and Cytokinesis Section 3: Cell Cycle Regulation Click on a lesson name to select.

Section 1 Cellular Reproduction Cellular Growth Ratio of Surface Area to Volume

Section 1 Cellular Reproduction Cellular Growth § As the cell grows, its volume increases much more rapidly than the surface area. § The cell might have difficulty supplying nutrients and expelling enough waste products.

Section 1 Cellular Reproduction Cellular Growth Transport of Substances § Substances move by diffusion or by motor proteins. § Diffusion over large distances is slow and inefficient. § Small cells maintain more efficient transport systems.

Section 1 Cellular Reproduction Cellular Growth Cellular Communications § The need for signaling proteins to move throughout the cell also limits cell size. § Cell size affects the ability of the cell to communicate instructions for cellular functions.

Section 2 Cellular Reproduction Cellular Growth The Cell Cycle § Cell division prevents the cell from becoming too large. § It also is the way the cell reproduces so that you grow and heal certain injuries. § Cells reproduce by a cycle of growing and dividing called the cell cycle.

Section 2 Cellular Reproduction Cellular Growth § Interphase is the stage during which the cell grows, carries out cellular functions, and replicates. §G 1 - cell growth §S - chromosomes are duplicated §G 2 - cell growth

Section 2 Cellular Reproduction Cellular Growth § Mitosis(M phase) is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide. § Cytokinesis(C phase) is the method by which a cell’s cytoplasm divides, creating a new cell.

Section 2

Section 1 Cellular Reproduction Cellular Growth The Stages of Interphase § The first stage of interphase, G 1 § The cell is growing, carrying out normal cell functions, and preparing to replicate DNA.

Section 1 Cellular Reproduction Cellular Growth The Second Stage of Interphase, S § S stands for synthesis of DNA § The cell copies its DNA in preparation for cell division.

Section 1 Cellular Reproduction Cellular Growth The Third Stage of Interphase, G 2 § The cell continues to grow and prepares for the division of its nucleus.

Section 2 Cellular Reproduction Mitosis and Cytokinesis The Stages of Mitosis § Prophase § The cell’s chromatin tightens and coils forming discrete chromosomes. § Sister chromatids are attached at the centromere. § Spindle fibers form in the cytoplasm.

Section 2 Cellular Reproduction Mitosis and Cytokinesis § The nuclear envelope and nucleolus seems to disappear. § Spindle fibers attach to the sister chromatids at centromere. § Whole structure including aster, centrioles, and spindle fibers is called the spindle apparatus

Section 2 Cellular Reproduction Mitosis and Cytokinesis Metaphase § Sister chromatids are pulled along the spindle apparatus toward the center of the cell § They line up in the middle of the cell (equator/metaphase plate).

Section 2 Cellular Reproduction Mitosis and Cytokinesis Anaphase § The microtubules of the spindle apparatus begin to shorten. § This causes sister chromatids separate into two identical chromosomes. § The chromosomes move toward the poles of the cell.

Section 2 Cellular Reproduction Mitosis and Cytokinesis Telophase § The chromosomes arrive at the poles and begin to relax/decondense. § Two new nuclear membranes begin to form and the nucleoli reappear. § The spindle apparatus disassembles.

Section 2 Cellular Reproduction Mitosis and Cytokinesis § Process that divides the cytoplasm and final step in cell division § In animal cells, microfilaments constrict, or pinch, the cytoplasm. This area of constriction is called the cleavage furrow § In plant cells, a new structure forms b/w the two daughter nuclei, called a cell plate. (formation of cell wall)

Section 2 http: //faculty. baruch. cuny. edu/jwahlert/bio 1003/mit osis. html

Section 2 Prokaryotes • Divide by binary fission – DNA duplicates and attach to P. M. – P. M. grows and pulls DNA molecules apart – Fission is completed w/formation of two new prokaryotic cells

Section 3 Cellular Reproduction Cell Cycle Regulation Normal Cell Cycle § Different cyclin/CDK combinations signal other activities, including DNA replication, protein synthesis, and nuclear division throughout the cell cycle.

Section 3 Cellular Reproduction Cell Cycle Regulation Quality Control Checkpoints § The cell cycle has built-in checkpoints that monitor the cycle and can stop it if something goes wrong. § Spindle checkpoints also have been identified in mitosis.

Section 3 Cellular Reproduction Cell Cycle Regulation Abnormal Cell Cycle: Cancer § Cancer is the uncontrolled growth and division of cells. § Cancer cells can kill an organism by crowding out normal cells, resulting in the loss of tissue function.

Section 3 Cellular Reproduction Cell Cycle Regulation Causes of Cancer § The changes that occur in the regulation of cell growth and division of cancer cells are due to mutations. § Various environmental factors can affect the occurrence of cancer cells.

Section 3 Cellular Reproduction Cell Cycle Regulation Apoptosis § Programmed cell death § Cells going through apoptosis actually shrink and shrivel in a controlled process.

Section 3 Cellular Reproduction Cell Cycle Regulation Stem Cells § Unspecialized cells that can develop into specialized cells when under the right conditions

Section 3 Cellular Reproduction Cell Cycle Regulation Embryonic Stem Cells § After fertilization, the resulting mass of cells divides repeatedly until there about 100– 150 cells. These cells have not become specialized.

Section 3 Cellular Reproduction Cell Cycle Regulation 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 Cellular Reproduction