1 / 20

Cell Reproduction

Explore the process of cell growth and division in living organisms. Learn about the different phases of the cell cycle and the role of chromosomes. Discover the regulation of the cell cycle and the implications of disruptions in cell division, such as cancer.

rsparks
Télécharger la présentation

Cell Reproduction

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cell Reproduction Chapter 10, 11-4

  2. Cells Grow! • Living organisms are made of cells. Like living organism, cells also go through periods of growth, and ultimately divide to produce more cells. • Cell growth is limited by: • DNA overload • Information/material exchange

  3. Cell Division • Chromosomes: • Condensed chromatin • During the cycle of a cell, chromosomes appear as X during mitosis. • These X-shaped chromosomes are made up of a pair of identical chromosomes, each called a Chromatid. • The chromatid are attached at a point called the Centromere. • During the life of a cell it follows a number of set steps that occur. These steps are called the Cell Cycle.

  4. Chromosomes • Each organism has a set number of chromosomes in its cells. • Humans for example have 46 chromosomes • Flies have 8 • There are 2 types of cells: • Autosomal: Non-sex cells. The cells in the rest of the body. • Gamete: Cells involved in sexual reproduction. • Haploid vs. Diploid • The total number of chromosomes in these 2 types of cells differ. In autosomal cells 2 sets of chromosomes exist. • In the sex cells (gametes) only 1 set of chromosomes exist.

  5. Chromosomes • In Humans: • 23 unique chromosomes (Haploid number = 23) • In autosomal cells: 46 chromosomes total OR 2 pairs of the 23 unique chromosomes. • In gametes 1 set of the unique 23 chromosomes.

  6. Cell Cycle • 2 Major phases to the Cell Cycle: • Occurs in somatic cells of organisms. • Interphase: “in-between” period • Mitosis – period of cell division • The result of the cell cycle are 2 identical cells called daughter cells.

  7. Cell Cycle • Mitosis and Interphase have subphases. In these subphases specific events occur. • Ultimately there needs to be an equal division of the cell contents in order to produce 2 healthy cells.

  8. Mitosis • Mitosis begins with one adult cell. • Through a series of steps, this adult cell spits into 2 identical daughter cells.

  9. Interphase • Has 3 major subphases. • G1, S, and G2

  10. Interphase • In G1 of Interphase the cell grows normally and performs its regular functions • In the S phase the DNA is replicated (double the DNA) • In G2 the cell makes ready to divide.

  11. Mitosis • Within the mitosis phase, there are 4 major subphases. • Each phase is clearly visible and has defining features.

  12. Prophase • This is the longest of the 4 mitosis phases. • In animal cells the centrosomes form on either side of the chromosomes. • Spindles (microtubules) attach the chromosomes to the centrosomes • The chromatin condenses to chromosomes. • The nuclear envelope and nucleolus disappear.

  13. Metaphase • Most obvious of the mitosis phases. • Chromosomes line up in the center of the cell (called metaphase plate). • Each chromosome is attached by spindle fibers to both centrosomes.

  14. Anaphase • The sister chromatids are separated by the pulling centromeres. • The chromosomes continue to move until they reach opposite polls of the cell.

  15. Telophase • The daughter cells begin to separate along the metaphase plate. • The chromosomes disperse into chromatin. • Meanwhile, the nuclear envelop begins to reform. As does the nucleolus. • The spindle fibers start to break apart.

  16. Cytokinesis • Occurs during Telophase! • Animal Cells • cell membrane pinches inwards • Plant Cells • Cell plate is formed from Golgi in cell membrane • Cell wall forms between this • Cell Plate Formation

  17. Regulating the Cell Cycle • Controls of Cell Cycle: • Cells can only divide a certain number of times. • Cells stop dividing when they come in contact with other cells (Known as Contact Inhibition).

  18. Regulation of Cell Cycle • Regulators of the Cell Cycle • A group of proteins known as cyclins regulate the timing of the events of the cell cycle. • Internal Regulators: proteins within the cell that respond to events, such as DNA replication, alignment of chromosomes. • External Regulators: proteins that respond to events outside the cell. Signal the cell to speed or slow down the cycle.

  19. Cancer • When cell cycle regulation goes wrong, the result is the formation of cancer. • Cancer cells are those that continuously divide, and ignore Cell Cycle regulation signals. • Cancer is caused by altering the regulators of the cell cycle. Many substances such as tobacco smoking, virus infections and radiation have lead to disruption of growth controlling proteins.

  20. Cancer • Cancer is caused by a number of mutations within a cell. It is not a one hit wonder!

More Related