Separating Dead from Alive Cell Membranes Separating Dead from Alive

Identify the radical below. Amine Hydroxyl Carboxyl Monosaccharide

Identify the molecule shown. Butene Propene Propane Butane None of the above are a good response.

What is the function of the molecule shown below? Energy storage Component of cell membrane Fuel source Regulatory

I. Functions Living part of the cell-legitimate cell organelle Separates living from the nonliving world Semipermeable-regulates what enters and exits the cell Partitions the cell into different regions where different functions take place Participates in chemical reactions Transmits signals between outside of cell and the cytoplasm[

II. Cell membrane characteristics A. Semipermeable B. Elastic C. Wettable D. Very thin-around 10 um

II. Early model A. Davison Danielli Model 1. mainly lipid 2. aqueous channels 3. surface protein 4. weaknesses

Phospholipids interacting in water-amphipathic

RBC cell membrane-clearly resembles Davson-Danielli model

III. Fluid mosaic model A. Main ingredients Phospholipids Proteins both intrinsic and extrinsic Cholesterol Glycocalyx

Your textbook’s Diagram

B. Protein functions

What do you think the function of this membrane protein might be? Transport Cell to cell adhesion Cell to cell recognition Energy production

Electron micrograph of cell membrane http://www.med.uiuc.edu/histo/large/atlas/image/temgi3/75000a1.htm

C. Chemical properties of membrane 1. Lateral fluidity 2. Two dimensional fluidity-rapid movement of lipids and proteins 3. Flexible 4. Self sealing 5. Can fuse

C. Chemical properties of membrane Effect of saturated vs. unsaturated Role of cholesterol

IV. Function of Cell Membrane-Passive Transport A. Diffusion 1. definition 2. example 3. across cell membrane

Your textbook’s figure of diffusion

IV. Function of Cell Membrane-Passive Transport B. Facilitated Diffusion 1. mediated by intrinsic protein 2. diffusion gradient-no ATP 3. glucose entrance into cell 4. boy scout analogy

C. Osmosis 1. Definition 2. U-tube 3. Explanation 4. Common examples 5. Terms of tonicity 6. Turgor pressure

In which direction will water move? A => B and B rises B => A and A rises A  B and the sides stay at the same level No idea

Your textbook’s figure of osmosis

Figure 5-13 Page 106 (a) Plasma membrane (b) Nucleus (c) Vacuole Vacuolar membrane (tonoplast) Figure 5-13 Page 106 Plasma membrane Cytoplasm

V. Function of cell membrane-active transport A. Definition B. Endocytosis 1. Phagocytosis http://www.youtube.com/watch?v=aWItglvTiLc

Phagocytic vesicles

Figure 5-19 Page 111 2. Pinocytosis Microvilli Pinocytotic vesicle Cytosol Figure 5-19 Page 111

3. Receptor mediated pinocytosis (b) Figure 5-20b Page 112

C. Exocytosis

D. Membrane Pumps Materials are moved against concentration gradient An integral protein molecule is involved ATP is necessary Sometimes membrane potentials are produced Na ion-K ion pump is an example

Figure 5-15b Page 108 (b) 2. A phosphate group is ATP ADP 2. A phosphate group is transferred from ATP to the transport protein 3. The transport protein under- goes a conformational change, releasing three sodium ions outside the cell. 1. Three sodium ions bind to the transport protein 4. Two potassium ions bind to the transport protein 6. The transport protein returns to its original shape: Two potassium ions are released inside the cell 5. The phosphate is released Figure 5-15b Page 108 (b)