Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 2.Discuss/Collect Evidence for life article 3.Cell Membrane Note 4.Osmosis/Diffusion LABS

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 2.Osmosis/Diffusion LABS 3.Membrane Notes

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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: 1.Do Now 2.PJAS/MCSRC announcements 3.Did you hand in your diffusion lab? 4.Homework - Chapter 5 Review Handout 5.IRP Presentations: 1.Sean 2.Nick M. 3.Sarah 4.Rose 5.Bjay 6.Stephen Tomorrow: 1.Lindsay 2.Patrick 3.Matt B. 4.Jeremy MCSRC Meeting WEDNESDAY – Jan. 5 th D20 Mrs. Biondo

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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: 1.Do Now 2.PJAS/MCSRC announcements 3.Did you hand in your diffusion lab? 4.Homework - Chapter 5 Review Handout 5.IRP Presentations: 1.Marissa 2.Suzie 3.Sang Tomorrow: 1.Jess Q. 2.Bea 3.Jen 4.Stephanie 5.Paul 6.Andy MCSRC Meeting WEDNESDAY – Jan. 5 th D20 Mrs. Biondo

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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: 1.Do Now 2.Complete IRP presentations 3.Complete Membrane Notes 4.Value of Villi Activity 5.Homework - Chapter 5 Review Handout

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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: 1.Do Now 2.Did you try the Enzyme Packet? 3.Go over Enzyme Packet 4.Review

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Plant cell H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O Plasma membrane (1) Normal (2) Lysed (3) Shriveled (4) Flaccid (5) Turgid (6) Shriveled (plasmolyzed) Isotonic solution Hypotonic solution Hypertonic solution Animal cell

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings MEMBRANE STRUCTURE AND FUNCTION 5.10 Membranes organize the chemical activities of cells Membranes –Provide structural order for metabolism

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The plasma membrane of the cell is selectively permeable –Controlling the flow of substances into or out of the cell Figure 5.10 Cytoplasm Outside of cell TEM 200,000 

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 CH 2 CH 3 CH 2 CH CH 2 CH 3 CH 2 CH 3 N + O O O–O– P O CH 2 CH CH 2 C O C O O O Phosphate group Symbol Hydrophilic head Hydrophobic tails

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Phospholipids form a two-layer sheet –Called a phospholipid bilayer, with the heads facing outward and the tails facing inward Figure 5.11B Water Hydrophilic heads Hydrophobic tails

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 Fibers of the extracellul ar matrix Carbohydrat e (of glycoprotein) Glycoprot ein Microfilame nts of cytoskeleto n Phospholi pid Choleste rol Protei ns Plasma membra ne Glycoli pid Cytopla sm

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Fibers of the extracellular matrix Carbohydrate (of glycoprotein) Glycoprotein Microfilaments of cytoskeleton Phospholipid Cholesterol Proteins Plasma membrane Glycolipid Cytoplasm

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 5.13 Proteins make the membrane a mosaic of function Many membrane proteins –Function as enzymes (biological catalysts – speed up reactions) Figure 5.13A

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Other membrane proteins –Function as receptors for chemical messages from other cells Figure 5.13B Messenger molecule Receptor Activated molecule

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Membrane proteins also function in transport –Moving substances across the membrane Figure 5.13C ATP

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 EquilibriumMembraneMolecules of dye Equilibrium Figure 5.14B Figure 5.14A

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Small nonpolar molecules such as O 2 and CO 2 –Diffuse easily across the phospholipid bilayer of a membrane

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 Solute molecule Transport protein

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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: 1.Do Now/Homework Check - Chapter 5 Review Handout 2.Complete Membrane Notes 3.Value of Villi Activity 4.Enzymes and Metabolism POGIL

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 Lower concentration of solute Higher concentration of solute Equal concentration of solute H2OH2O Solute molecule Selectively permeable membrane Water molecule Solute molecule with cluster of water molecules Net flow of water

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 Plant cell H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O Plasma membrane (1) Normal (2) Lysed (3) Shriveled (4) Flaccid (5) Turgid (6) Shriveled (plasmolyzed) Isotonic solution Hypotonic solution Hypertonic solution Animal cell

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings The control of water balance –Is called osmoregulation

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings P P P Protein changes shape Phosphate detaches ATP ADP Solute Transport protein Solute binding1Phosphorylation2 Transport 3 Protein reversion Cells expend energy for active transport Transport proteins can move solutes against a concentration gradient –Through active transport, which requires ATP Figure 5.18

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Fluid outside cell Cytoplasm Protein Vesicle 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

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Membranes may fold inward –Enclosing material from the outside (endocytosis) Figure 5.19B Vesicle forming

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings Endocytosis can occur in three ways –Phagocytosis –Pinocytosis –Receptor-mediated endocytosis Pseudopodium of amoeba Food being ingested Phagocytosis Pinocytosis Receptor-mediated endocytosis Material bound to receptor proteins PIT Cytoplasm Plasma membrane TEM 54,000  TEM 96,500  LM 230  Figure 5.19C

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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 LDL particle Protein Phospholipid outer layer Cytoplasm Receptor protein Plasma membrane Vesicle Cholesterol Figure 5.20

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 5.21 Chloroplasts and mitochondria make energy available for cellular work Enzymes are central to the processes that make energy available to the cell

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings 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