University:
High School
Course:
High School Chemistry
Academic year:

2022
Views:

355

Pages:

20
Author:

larbiwxcvbn

Transport Mechanisms through Cell Membranes Passive vs. Active Transport Essential Questions 1. Define passive transport. (Related to Essential Skill 3-4) 2. Describe and give an example of diffusion. (Related to Essential Skill 3-4) 3. Compare and contrast diffusion and osmosis. (Related to Essential Skill 3-4) 4. Explain how facilitated diffusion differs from diffusion in general. Passive Transport  Movement of molecules through the cell membrane  Movement is from high to low concentrations  Does NOT require energy.  3 Types of Passive Transport:  Diffusion  Osmosis  Facilitated Diffusion 1. Diffusion  Movement of molecules from high concentration to low concentration.  Why can you smell popcorn from another room?  Why does food coloring mix by itself?  How does oxygen get into your blood? Selectively Permeable = cell membrane will only allow some things through!  Large macromolecules and charged ions can NOT get through the lipid bi-layer!!! 2. Facilitated Diffusion  Diffusion with the help of “channel” proteins. - Usually because molecules are too big or have a charge and can not go through the membrane alone. 3. Osmosis  Osmosis is the Diffusion of WATER!!!!!  Water moves from areas with more water to areas with less water  Why do your fingers get wrinkles when you swim too long?  Have you ever put salt on a slug??? Solutions & Solutes  A solution is a liquid with another substance dissolved in it  Examples: salt water & sugar water  A solute is the “stuff” that is dissolved in a solution  Examples: salt & sugar Solute + Solvent = Solution  In osmosis we trace the movement of the water, not the solute Three Types of Osmosis  Hypertonic Environment  Solutions that have MORE “stuff” and less water than the cell.  Water will move OUT of cell. Isotonic Environment  Solution has the SAME amount of “stuff” and water as the cell.  There is no net gain or loss of water from the cell.  Water moves equally in and out of the cell Hypotonic Environment  Solution has LESS “stuff” and more water than the cell.  Water will move INTO cell. ACTIVE TRANSPORT Essential Questions 1. Define active transport. (Related to Essential Skill 3-4) 2. Describe and give an example of a protein pump. (Related to Essential Skill 3-4) 3. Compare and contrast endocytosis and exocytosis. (Related to Essential Skill 3-4) 4. Explain how protein pumps differ from facilitated diffusion. (Related to Essential Skill 34) Active Transport  Movement of molecules across the membrane from low to high concentration.  Requires ENERGY.  3 Types of Active Transport: - Protein PUMPS - Endocytosis - Exocytosis Riding a bicycle uphill = Active Transport analogy (NOT actual passive transport!) Protein “Pumps” Proteins that “pump” or move molecules from Low concentration to High concentrations - requires energy. Endocytosis  Active transport of large particles INTO the cell, by surrounding them with the cell membrane. Exocytosis  Active transport of substances OUT of the cell using the cell membrane – Exiting the cell Transport Analogy Concentration Mountain – how to remember Active Transport Passive Transport Diffusion Osmosis Facilitated Diffusion No Energy Protein pumps Endocytosis Exocytosis Concentration gradient Uses Energy Summary