Presentation on theme: "Thursday 1/30/14 AIM: How is the structure of the plasma membrane related to its function? DO NOW: In complete sentences, explain why every cell has a."— Presentation transcript:
Thursday 1/30/14 AIM: How is the structure of the plasma membrane related to its function? DO NOW: In complete sentences, explain why every cell has a cell membrane. Homework: The cell handout
Functions Helps to maintain balance or homeostasis within the cell Boundary between cell and its environment Selectively permeable: allows some to pass and others are kept out
The Plasma Membrane - YouTube The Plasma Membrane - YouTube
Membrane proteins: help molecules move across the membrane Integral proteins: big enough to span both layers of the membrane Peripheral proteins: only found on the surface of the membrane –Usually only span one layer of phospholipids
How do fibrous proteins, globular proteins and cholesterol create a fluid mosaic?
How do membrane proteins assist in protecting the cell?
Membrane proteins Fibrous proteins: receptors Glycoproteins:cell to cell recognition or identification Pore proteins: passive transport Channel proteins: active transport
Thursday 12/6/12 AIM: How does the plasma membrane regulate movement of molecules into and out of the cell? DO NOW:Explain the difference between hydrophobic and hydrophillic. Which part of the cell membrane is hydrophobic? Hydrophillic? HOMEWORK: Textbook read pages 175-177. answer the reading check questions on pages 175 and 176. Question 3 on page 177
POP QUIZ 1- What are the 2 other names for the cell membrane? 2- why is it important for the cell membrane to be partly hydrophobic and partly hydrophillic?
Why is it important for the membrane to be partly hydrophobic and partly hydrophillic?
Why does the membrane need cholesterol? Helps stabilize the membrane Dissolve in the hydrophobic tail to make the membrane liquid
Cell Membrane proteins Integral proteins –Function is to help molecules move across the membrane –Span both layers of phospholipids Peripheral proteins –Function in cell top cell recognition –Also assist in molecular movement –Only span one layer of the phospholipid bilayer
Glycoproteins Part carbohydrate (glyco) Part protein These are peripheral Help in cell to cell recognition
Fluid Mosaic model Individual phospholipids are not bonded Fluid because phospholipids move within the membrane At the same time, proteins in the membrane also move among the phospholipids These proteins create a mosaic model
Why is the plasma membrane selectively permeable?
In complete sentences explain what you would do in the following situation: You are at a dance that contains 100 kids within 1 hour the dance fills up with 800 kids and you can hardly move. What would you do and why?
How do molecules move across the plasma membrane?
Transport Passive: molecules move from a high to low concentration Active: molecules move from low to high concentration
Transport across the membrane cytoplasm has different molecules and ions. Some easily pass through the plasma membrane into the cell. These include water, oxygen and glucose molecules, and sodium and chloride ions.
Passive Transport Small lipid soluble molecules move from a crowded area to a less crowded area Down the concentration gradient No energy is required
Assessment Use your notes to design a well organized table using the parts and the functions that build the plasma membrane
Diffusion Movement is driven by concentration gradient Molecules move from an area of high concentration to low concentration Solute concentration is equal
Facilitated diffusion Some molecules are too big to passively diffuse So they need the help of carrier proteins Transport is still driven by a concentration gradient
What are the different types of transport? Passive and active
How are passive and active transport different? Passive: driven by concentration gradient Active: driven by ATP
Osmosis Simple diffusion of water From an area of higher concentration to a region where they are in a lower concentration
Isotonic: equal movement of water into and out of cell
Hypotonic solution: net water movement into the cell
Hypertonic: net movement of water out of the cell
Friday 11/18/05 Aim: Why does the cell use energy to move molecules across the cell membrane? Do Now: Use your table from yesterday or create a new table organizing the osmotic environments and the flow of water in each. In a third column of your table, draw a picture of each using an x to represent solute molecules and o to represent water molecules. Homework: study for tuesdays exam
How does the concentration gradient determine the direction of molecule movement across the cell membrane?
Active transport Movement of substances against a concentration gradient From low to high Needs energy Membrane proteins use energy to move individual molecules
How does active transport differ from facilitated diffusion?
How is active transport different from passive transport? Passive transport does not need energy to move molecules from high to low concentration Active Transport uses energy to move molecules against the concentration gradient
Why is active transport necessary for homeostasis? Certain molecules need to enter or leave the cell against their concentration gradient
12/5/07 Wednesday AIM: How do molecules actively cross the cell membrane? DO NOW: Create a Venn diagram showing the differences between active and passive transport HW: textbook page 197 Questions 6 and 21
Northland College Education Biology Animation Transport processes Requiring ATP
Active transport Endocytosis: cell uses energy to carry molecules inside Exocytosis: remove contents from the cell Ion pumps Co-transport
Active transport Endocytosis: intake of particles or fluids in to the cell Pinocytosis: cell drinking Phagocytosis: cell eating