* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 7 Membrane Structure and Function
Survey
Document related concepts
Cellular differentiation wikipedia , lookup
Cell nucleus wikipedia , lookup
Membrane potential wikipedia , lookup
Lipid bilayer wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Model lipid bilayer wikipedia , lookup
G protein–coupled receptor wikipedia , lookup
SNARE (protein) wikipedia , lookup
Cell growth wikipedia , lookup
Magnesium transporter wikipedia , lookup
Extracellular matrix wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cytokinesis wikipedia , lookup
Signal transduction wikipedia , lookup
Cell membrane wikipedia , lookup
Transcript
Chapter 7 Membrane Structure and Function Days 8 Objectives -You will understand that membranes are fluid -The structure results in a semi-permeable membrane -Passive transport requires no energy -Active transport requires energy -Bulk transport of molecules either by exocytosis or by endocytosis. Lab 1: Diffusion and Osmosis p. 127 Cell Membranes Are Made up of Macromolecules Lipids -Specifically Phospholipids -Form a bilayer with nonpolar, hydrophobic region in the middle. Proteins -Various proteins are embedded. Carbohydrates -Carbohydrates extend out and old the cell in place to the ECM Factors That Affect The Fluidity Of The Membrane - Cell membranes are mainly held together by nonpolar attractions --- Much weaker then covalent bonds - Movement of lipids - Saturated Vs Unsaturated fats - Cholesterol **Cell Membrane Sidedness P 130 Types: 1. Integral 2. Peripheral Functions: Cellular Proteins 1. Transport -Hydrophobic Channel -Shuttle uses ATP 2. Enzymes -Use of Active Site -Often grouped together 3. Signal Transduction -Acts in cellular comunication -Uses a receptor site 4. Cell Recognition -Glycoproteins -Immune system 5. Inter Cellular Joining -Used in various types of junctions 6. Attachment proteins -Stablize internal organelles and cell Membranes are Selectively Permeable Passive Diffusion: Movement of solutes from a high concentration to a lower concentration. -Takes No Energy to move -In Cell Biology we are talking about movement across the cell membrane Osmosis: Passive diffusion of water. Facilitated Diffusion: Passive diffusion of large solutes through protein channels Active Transport -Takes Energy -Increases gradient -Gradient is used for cellular work Passive Transport -Takes no energy -Common property of life -The goal is homeostasis Active Transport -Na/K pump makes use of protein shape and changing ion affinity -ATP reacts – Phophate changes shape of protein -Membranes can have a electronic potential based on their electrochemical gradient -Electrogeneic pump is a membrane protein that increases the electrochemical gradient Ion pump Co-transport -Pump creates a gradient -Use of property of homeostasis to transport large molecules like sucrose Exocytosis -Transport vesicles inside cell combine with cell membrane and release contents to the exterior of the cell. -Transport occurs along microtubules Endocytosis 1. Phagocytosis - Engulf food particles into a food vacuole for digestion - Ameobas and pseudopods 2. Pinocytosis is gulping of extracellular fluid 3. Receptor Mediated Endocytosis -Ligands attach to specific -LDL (Low Density Lipoproteins) p. 138