1 / 30

12/16/10

12/16/10. Objective: To understand the structure and function of the cell membrane Do Now: What is meant by “fluid mosaic” model as a description for the membrane?. Today: 1. Do Now/Sign - up for presentations Discuss/Collect Evidence for life article Cell Membrane Note

leona
Download Presentation

12/16/10

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. 12/16/10 • Objective: To understand the structure and function of the cell membrane • Do Now:What is meant by “fluid mosaic” model as a description for the membrane? • Today:1. Do Now/Sign - up for presentations • Discuss/Collect Evidence for life article • Cell Membrane Note • Osmosis/Diffusion LABS

  2. 12/17/10 • Objective: To understand the structure and function of the cell membrane • Do Now:What is diffusion? How do molecules flow? • Today:1. Do Now/Collect Evidence for Life Article • Osmosis/Diffusion LABS • Membrane Notes

  3. 1/3/11 – “E” day • Objective: To understand the structure and function of the cell membrane • Do Now:What is osmosis? How do cells behave in a hypotonic solution?hypertonic solution?isotonic solution? • Today: • Do Now • PJAS/MCSRC announcements • Did you hand in your diffusion lab? • Homework - Chapter 5 Review Handout • IRP Presentations: • Sean • Nick M. • Sarah • Rose • Bjay • Stephen MCSRC Meeting WEDNESDAY – Jan. 5th D20 Mrs. Biondo Tomorrow: Lindsay Patrick Matt B. Jeremy

  4. 1/3/11 – “E” day • Objective: To understand the structure and function of the cell membrane • Do Now:What is osmosis? How do cells behave in a hypotonic solution?hypertonic solution?isotonic solution? • Today: • Do Now • PJAS/MCSRC announcements • Did you hand in your diffusion lab? • Homework - Chapter 5 Review Handout • IRP Presentations: • Marissa • Suzie • Sang Tomorrow: Jess Q. Bea Jen Stephanie Paul Andy MCSRC Meeting WEDNESDAY – Jan. 5th D20 Mrs. Biondo

  5. 1/6/11 – “B” day • Objective: To understand the structure and function of the cell membrane • Do Now:What is active transport across a membrane? Passive transport? • Today: • Do Now • Complete IRP presentations • Complete Membrane Notes • Value of Villi Activity • Homework - Chapter 5 Review Handout

  6. 1/10/11 – “D” day • Objective: To understand the function of enzymes in metabolism • Do Now:What is ATP, what is it used for? Today: Do Now Did you try the Enzyme Packet? Go over Enzyme Packet Review

  7. Hypertonic solution Hypotonic solution Isotonic solution H2O H2O H2O H2O Animalcell (3) Shriveled (2) Lysed (1) Normal Plasmamembrane H2O H2O H2O H2O Plantcell (6) Shriveled (plasmolyzed) (5) Turgid (4) Flaccid

  8. MEMBRANE STRUCTURE AND FUNCTION • 5.10 Membranes organize the chemical activities of cells • Membranes • Provide structural order for metabolism

  9. Outside of cell Cytoplasm TEM 200,000  • The plasma membrane of the cell is selectively permeable • Controlling the flow of substances into or out of the cell Figure 5.10

  10. CH3 Hydrophilic head + N CH2 CH3 CH3 CH2 Phosphategroup O P O– O O CH CH2 CH2 O O O O C C CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 Symbol CH CH2 CH CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH3 CH3 Hydrophobic tails • 5.11 Membrane phospholipids form a bilayer • Phospholipids • Have a hydrophilic head and two hydrophobic tails • Fatty Acid chains! • Are the main structural components of membranes Figure 5.11A

  11. Water Hydrophilicheads Hydrophobictails Water • Phospholipids form a two-layer sheet • Called a phospholipid bilayer, with the heads facing outward and the tails facing inward Figure 5.11B

  12. Fibers of the extracellular matrix Carbohydrate(of glycoprotein) Glycoprotein Glycolipid Plasmamembrane Phospholipid Proteins Microfilamentsof cytoskeleton Cholesterol Cytoplasm • 5.12 The membrane is a fluid mosaic of phospholipids and proteins • A membrane is a fluid mosaic • With proteins and other molecules embedded in a phospholipid bilayer Figure 5.12

  13. Fibers of the extracellular matrix Carbohydrate(of glycoprotein) Glycoprotein Glycolipid Plasmamembrane Phospholipid Proteins Cholesterol Microfilamentsof cytoskeleton Cytoplasm

  14. 5.13 Proteins make the membrane a mosaic of function • Many membrane proteins • Function as enzymes (biological catalysts – speed up reactions) Figure 5.13A

  15. Messenger molecule Receptor Activatedmolecule • Other membrane proteins • Function as receptors for chemical messages from other cells Figure 5.13B

  16. ATP • Membrane proteins also function in transport • Moving substances across the membrane Figure 5.13C

  17. Molecules of dye Membrane Equilibrium Equilibrium • 5.14 Passive transport is diffusion across a membrane • In passive transport, substances diffuse through membranes without work by the cell • Spreading from areas of high concentration to areas of low concentration Figure 5.14A Figure 5.14B

  18. Small nonpolar molecules such as O2 and CO2 • Diffuse easily across the phospholipid bilayer of a membrane

  19. Solutemolecule Transportprotein • 5.15 Transport proteins may facilitate diffusion across membranes • Many kinds of molecules • Do not diffuse freely across membranes • For these molecules, transport proteins • Provide passage across membranes through a process called facilitated diffusion Figure 5.15

  20. 1/7/11 – “C” day • Objective: To understand the structure and function of the cell membrane • Do Now:What would likely happen to an animal cell placed in a hypotonic solution? A hypertonic solution? Why are animal cells different? • Today: • Do Now/Homework Check - Chapter 5 Review Handout • Complete Membrane Notes • Value of Villi Activity • Enzymes and Metabolism POGIL

  21. Equalconcentrationof solute Higherconcentrationof solute Lowerconcentrationof solute H2O Solutemolecule Selectivelypermeablemembrane Watermolecule Solute molecule with cluster of water molecules Net flow of water • 5.16 Osmosis is the diffusion of water across a membrane • In osmosis • Water travels from a solution of lower solute concentration to one of higher solute concentration Figure 5.16

  22. Hypertonic solution Hypotonic solution Isotonic solution H2O H2O H2O H2O Animalcell (3) Shriveled (2) Lysed (1) Normal Plasmamembrane H2O H2O H2O H2O Plantcell (6) Shriveled (plasmolyzed) (5) Turgid (4) Flaccid • 5.17 Water balance between cells and their surroundings is crucial to organisms • Osmosis causes cells to shrink in hypertonic solutions • And swell in hypotonic solutions • In isotonic solutions • Animal cells are normal, but plant cells are limp Figure 5.17

  23. The control of water balance • Is called osmoregulation

  24. Transportprotein P P P Phosphatedetaches Proteinchanges shape ATP Solute ADP Transport 1 Solute binding 2 Phosphorylation 3 4 Protein reversion • 5.18 Cells expend energy for active transport • Transport proteins can move solutes against a concentration gradient • Through active transport, which requires ATP Figure 5.18

  25. Fluid outside cell Vesicle Protein Cytoplasm • 5.19 Exocytosis and endocytosis transport large molecules • To move large molecules or particles through a membrane • A vesicle may fuse with the membrane and expel its contents (exocytosis) Figure 5.19A

  26. Vesicle forming • Membranes may fold inward • Enclosing material from the outside (endocytosis) Figure 5.19B

  27. Plasma membrane Food being ingested Pseudopodium of amoeba Material bound to receptor proteins PIT TEM 96,500  TEM 54,000 Cytoplasm LM 230 Phagocytosis Receptor-mediated endocytosis Pinocytosis • Endocytosis can occur in three ways • Phagocytosis • Pinocytosis • Receptor-mediated endocytosis Figure 5.19C

  28. Phospholipid outer layer LDL particle Vesicle Cholesterol Protein Plasmamembrane Receptorprotein Cytoplasm CONNECTION • 5.20 Faulty membranes can overload the blood with cholesterol • Harmful levels of cholesterol • Can accumulate in the blood if membranes lack cholesterol receptors Figure 5.20

  29. 5.21 Chloroplasts and mitochondria make energy available for cellular work • Enzymes are central to the processes that make energy available to the cell

  30. Chloroplasts carry out photosynthesis • Using solar energy to produce glucose and oxygen from carbon dioxide and water • Mitochondria consume oxygen in cellular respiration • Using the energy stored in glucose to make ATP

More Related