1 / 21

Chapter 8

Chapter 8. I. Diffusion and Osmosis A. Process by which molecules spread from areas of high concentration to areas of low concentration 1.When molecules are even throughout a space it’s called equilibrium 2. Concentration gradient- a difference between concentrations in a space.

blaise
Télécharger la présentation

Chapter 8

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 8 I. Diffusion and Osmosis A. Process by which molecules spread from areas of high concentration to areas of low concentration 1.When molecules are even throughout a space it’s called equilibrium 2. Concentration gradient- a difference between concentrations in a space

  2. B. Osmosis 1. The movement of water 2. Membrane is selectively permeable, meaning it allows some things in and out 3. Water and oxygen can move freely across the cell membrane by diffusion 4. Water will move in the direction of more solute (or low water concentration)

  3. C. Salt Sucks! 1. Salt is a solute, when concentrated inside or outside the cell, water will go (be sucked) in the direction of the high salt concentration 2. Types of solutions: a. Isotonic: means same. Concentration of solute is equal on both sides. Water will move back and forth but won’t have a result on either side

  4. b. Hypotonic- means less, less solute outside the cell, salt sucks so water moves into the cell • Cell gains water & grows larger • In plant cells, central vacuoles fill, cell becomes stiff & rigid- cell wall keeps cell from bursting • In animal cells, cell may be in danger of bursting, so contractile vacuoles pump water of the cell

  5. c. Hypertonic means more- more salt molecules outside the cell- water leaves the cell • In plant cells, the vacuole loses water and the cells shrink, causing wilting • In animal cells, cells shrink • In both cases, cells could die • Dangerous to drink sea water- causes more dehydration. Salting fields used as war tactic to reduce food supply of enemy

  6. D. Active Transport 1. When cells must move materials in an opposite direction - against a concentration gradient. a. Active transport requires Energy. b. Proteins or Pumps are found in the cell membrane transport molecules across the membrane. Proteins are used to move small molecules such as calcium, potassium, and sodium ions across the membrane

  7. 2. Endocytosis- cell takes in large particles by engulfing them 3.Phagocytosis- "cell eating" - extensions of cytoplasm surround a particle and then the cell engulfs it.

  8. 4. Pinocytosis- the process of taking up liquid from the surrounding environment. 5. Exocytosis- cell gets rid of particles, opposite of endocytosis

  9. II. Cell Growth A. Limits to Cell Growth 1. Exchanging Materials- hard to get waste out 2. Cells are limited in size by their SURFACE AREA and VOLUME ratio B. CELL DIVISION - Process where a cell splits into two identical daughter cells 1. Mitosis - division of the nucleus 2. Cytokinesis - division of the cytoplasm

  10. C. CHROMOSOMES 1. Made of DNA a. twisted ladder shape called double helix b. carries the code to make the proteins for specific cell functions c. base order carries the code -adenine, guanine, cytosine, thymine 2. Found in Nucleus 3. Number depends on organism

  11. D. CELL CYCLE - events cells go through as they grow and divide

  12. START HERE!

  13. 1. Interphase- growth and development phase performing cell functions a. DNA replicates (copies) b. Organelles double in number, to prepare for division 2. Mitosis- phase of cell cycle where cells divide (reproduce) a. four phases -prophase: chromosomes wind up and become visible -metaphase: chromosomes line up in the middle of the cell (at the equator) -anaphase- spindle fibers pull chromosomes away from middle, to opposite poles -telophase- two nuclei are visible, nuclear membrane forms around each group of chromosomes, chromosomes unwind - during this phase, cytokinesis takes place: the cytoplasm is “cut” or separated to form two new cells

  14. prophase metaphase

  15. anaphase telophase

  16. 3. Cells divide at different rates, depending on the cell type a. Nerve and muscle cells usually stop dividing once developed b. Skin cells divide frequently as skin is being replaced constantly 4. What Controls Cell Division? a. Cell cycle regulators Internal regulators External regulators 5. When control of the cell cycle fails, cells begin to divide uncontrollably, resulting in masses and failure of the cells to perform their normal functions. This condition is called cancer.

  17. 6. Cancer = uncontrolled cell growth • Takes over the cell cycle • Causes can be environmental, genetic, viruses 7. Vaccines against cancer? • Gardasil is a vaccine that protects against HPV and can therefore protect females from certain kinds of cervical cancer. Your Opinion: Answer in your notebook • This vaccine must be administered at a young age before sexual activity. Some states want to require this vaccine for all young girls. *Do you think the government should require this vaccine?

  18. Cancer Research ASSIGNMENT Working in groups of 2 or 3, select one type of cancer you are interested in researching online. In your science notebooks, tell me the symptoms associated with the type of cancer you selected, how it impacts the body, how it is diagnosed, how it is treated, and whether it is considered life threatening. Each person in the group should write this information in their notebook to receive credit for completing the assignment.

More Related