1 / 12

Chapter 9

Chapter 9. Cellular Reproduction. THEME FOCUS. Cells go through several changes as they GROW and REPRODUCE. BIG Idea. Cells go through a life cycle that includes INTERPHASE , MITOSIS , and CYTOKINESIS. MAIN Idea.

sen
Download Presentation

Chapter 9

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. Chapter 9 Cellular Reproduction

  2. THEME FOCUS • Cells go through several changes as they GROW and REPRODUCE

  3. BIG Idea • Cells go through a life cycle that includes INTERPHASE, MITOSIS, and CYTOKINESIS

  4. MAIN Idea • Cells grow until they reach their SIZE limit, then they either stop growing or DIVIDE

  5. Cell Size Limitations • Most cells are less than 100 µm, which is smaller than the period at the end of this sentence. • The size of a cell is limited by its ratio of SURFACEAREA to its VOLUME • The SURFACE AREA is the area covered by the plasma membrane • The VOLUME is the space taken up by the inner contents of the cell

  6. Ratio of Surface Area to Volume • To calculate the surface area of a cube shaped cell, the following formula is used: • LENGTH x WIDTH x number of SIDES (6) • To calculate the volume of a cube shaped cell, the following formula is used: • LENGTH x WIDTH x HEIGHT

  7. Ratio of Surface Area to Volume • The surface area of the small cell shown above is 6 µm2and the volume is 1 µm3. Therefore the ratio of surface area to volume is 6:1

  8. Ratio of Surface Area to Volume • The surface area of the medium cell shown above is 24 µm2and the volume is 8 µm3. Therefore the ratio of surface area to volume is 3:1

  9. Ratio of Surface Area to Volume • The surface area of the large cell shown above is 96 µm2and the volume is 64 µm3. Therefore the ratio of surface area to volume is 3:2

  10. Ratio of Surface Area to Volume • As the cell grows, its VOLUME increases much more rapidly than the SURFACE AREA. • This means that the cell might have difficulty supplying NUTRIENTS (FOOD & OXYGEN) and expelling enough WAST PRODUCTS (CARBON DIOXIDE). • By remaining small, cells have a GREATER surface area to volume ratio and can therefore sustain themselves more easily.

  11. Transport of Substances • The movement of substances can be managed more easily in a SMALL cell than in a LARGE cell. • Recall, it is the selectively permeable PLASMA MEMBRANE that controls cellular transport • Once inside, substances move by DIFFUSION or by motor proteins pulling them along the CYTOSKELTON • SMALL size maximizes the ability of diffusion and motor proteins to transport NUTRIENTS and WASTE PRODUCTS

  12. Cellular Communications • Cell SIZE affects the ability of the cell to communicate instructions for cellular functions • If it becomes too LARGE, it becomes almost impossible for cellular communications to take place efficiently

More Related