* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Cell Membrane and Transport
Survey
Document related concepts
Biochemical switches in the cell cycle wikipedia , lookup
Cell nucleus wikipedia , lookup
Cell encapsulation wikipedia , lookup
Cytoplasmic streaming wikipedia , lookup
Extracellular matrix wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell culture wikipedia , lookup
Signal transduction wikipedia , lookup
Cell growth wikipedia , lookup
Organ-on-a-chip wikipedia , lookup
Cell membrane wikipedia , lookup
Cytokinesis wikipedia , lookup
Transcript
Transport Aim: How are molecules transported into and out of a cell? I. Why is transport important? A. Transport - the process by which substances move into or out of cells or are distributed within cells. B. Provides: 1. Circulation: movement of materials throughout an organism. 2. Absorption: the passage of material across a cell membrane into a cell. a. Process by which usable materials are taken into an organism. II. Cell Membrane A. Selectively (semi) permeable 1. Only lets certain things into and out of cell. 2. CAN PASS THROUGH: water, glucose, amino acids, carbon dioxide, fatty acids, glycerol. 3. CANNOT PASS THROUGH: starch, protein, lipids. III. Structure of the Cell Membrane A. Composed of proteins, lipids and carbohydrates. B. Made up of a bi-layer (2 layers) of lipids (fats). C. Proteins run between lipid bi-layer on the inside of cell and outside of cell. D. “Fluid Mosaic Model” 1. Represents the various molecules attached together in the cell membrane. 2. Mosaic: pieces or parts; different pieces put together to make a final product. 3. Fluid: move freely; moving all the time. Cross Section of a Cell Membrane IV. Movement of Materials A. Passive and Active Transport 1. Passive Transport: transport that does not require energy from the cell. Materials can pass right through. a. Diffusion: the movement of molecules or particles from an area of high concentration to an area of low concentration. High Just sit back and enjoy! Hill Low a. Diffusion Continued…. i. Concentration gradient: difference between high and low concentration *must be present in order for diffusion to occur. ii. Molecules become evenly distributed throughout available space. 1. Passive Transport – continued… B. Osmosis: Diffusion of water molecules. i. High concentration of water molecules to low concentration of water molecules. ii.Water molecules are highest in pure (distilled) water. iii. As water enters a cell, pressure will cause the cell to expand = osmotic pressure. iv. Isotonic solution: concentration of water molecules is the same inside and outside of cell. (a) No movement, concentration gradient is zero. C. Osmosis Continued… v. Hypertonic solution: more water molecules inside the cell causing the cell to shrink. (a) Movement of water out of cell. (b) Animal cell shrinks. (c) Plant cell vacuole collapse and cytoplasm shrinks. **Plasmolysis: shrinking of the cytoplasm vi. Hypotonic solution: less water molecules inside the cell causing the cell to expand. (a) Movement of water is into the cell. (b) Animal cell bursts. (c) Excessive water causes RBC’s to lyse (break). (d) Plant cell collects water in the vacuole. Plant Cell Hypotonic Solution Hypertonic Solution Isotonic Hypertonic 2. Active Transport A. When movement of molecules or particles across a cell membrane requires cellular energy. B. Usually involves movement of materials against the concentration gradient. Going from low to high concentration. High Hill Low “Oh no, look at that hill! Its going to take a lot of energy to get up it!” 2. Active Transport - continued C. Use of transport proteins. D. Membrane vesicles: materials become enclosed within an inpocketing of the cell membrane. 1. Endocytosis: transporting materials into a cell by vesicles. a. Phagocytosis: solid particles are ingested into the cell. b. Pinocytosis: small amounts of liquid are taken into the cell. Phagocytosis Pinocytosis V. Transport in Organisms A. Simple Organisms: cells are in close contact with outside environment. B. Large or Complex organisms: need a circulatory system. C. Circulatory system: system that links the cells of a complex organisms with its environment. VI. Circulatory System Made up of 3 parts: A. A fluid in which materials are transported. Ex. Blood B. A network of tubes or body spaces through which fluid flows. Ex. Arteries, Veins, & Capillaries C. A means of driving the fluid through the tubes or spaces. Ex. Pumping Heart