* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Cellular Transport
Survey
Document related concepts
Cell growth wikipedia , lookup
Tissue engineering wikipedia , lookup
Extracellular matrix wikipedia , lookup
Signal transduction wikipedia , lookup
Cellular differentiation wikipedia , lookup
Cell membrane wikipedia , lookup
Cytokinesis wikipedia , lookup
Cell culture wikipedia , lookup
Cell encapsulation wikipedia , lookup
Endomembrane system wikipedia , lookup
Transcript
Cellular Transport Ch. 1 Sec. 4 Why transport? • Cells need to –take in supplies –get rid of wastes –send out products Control of transport • Cell membrane –Selectively permeable –Some things can pass through –Others cannot Types of transport • Diffusion • Osmosis • Active transport Concentration • The amount of substance in a given volume • Like density High concentration Low concentration Diffusion • The movement of molecules from areas of high concentration to areas of low concentration Why does it happen? • Molecules are always moving • higher concentration bump into one another more • When they bump they spread out • Demo Result • Diffusion happens until molecules are evenly distributed Osmosis • The diffusion of water • Based on the concentration of water molecules • More “stuff” lower water concentration Animal cells If the concentrations are the same on both sides of the membrane then water moves equally in both directions Outside Cell Plant cells Animal cells If the concentration of stuff is higher outside the cell then there is movement of water outside causing the cell to shrink. Outside Cell Plant cells Animal cells If the concentration of stuff is lower outside the cell then there is a net movement of water inside the cell, causing swelling or breakage. Outside Cell Plant cells Animal cells Outside Cell Outside Cell Outside Cell Plant cells Active Transport • When energy is needed to get materials through the membrane • Osmosis and diffusion = passive transport Active Transport • Needed when: –Molecules needs to move from areas of low concentration to areas of high concentration –Molecules are too large to fit through membrane Active Transport • Cells use special proteins in the membrane to help get things in and out = transport proteins • Need energy to make protein work Video Active Transport • Large molecules can enter the cell by being engulfed • Also requires energy Why are cells so small? 1. If they get too big, there isn’t enough cell membrane to let in enough nutrients and materials • Volume (inside) grows faster than surface areas (outside) Why are cells so small? 2. Once through the membrane, materials spread through cell by cytoplasm streaming • Would take too long in big cells for stuff to reach center Why are cells so small? 3. There would be too much activity going on for one nucleus to control • If they get too big divide into two cells or die