The Cell Membrane

Monday, October 19, 2015 Do Now: In your TOC (orange)… #710/19Notes Transport Note Packet Imagine you are equipped with a cell membrane blaster. What would happen to a cell if you blasted its membrane away? (Hint: Think of the functions of the plasma/cell membrane.) Do you owe me any late/absent work? Hand it in now!! Did you miss a lab? Fill out a make-up lab request form!!

Cell Membrane –Protection –Support –Selectively permeable Regulates what enters and leaves cell –Structure Phospholipid P Hydrophilic Hydrophobic

How do materials enter and exit the cell??? By passive or active transport.

TRANSPORT The movement of materials through the cell membrane in order to create a state of equilibrium

CELL MEMBRANE: ● controls what enters and leaves the cell ● It is SELECTIVELY PERMEABLE, allowing only certain materials to pass into and out of the cell. ● Is a double layer sheet called a LIPID BILAYER

2 layers of phospholipids that give the cell a flexible & strong barrier between cell & environment Protein molecules embedded Carbohydrate Chains (outside the cell) Lipid Bilayer

Exit Question Why is the cell membrane composed of lipids (fats)?

Tuesday, October 20, 2015 Do Now: In your TOC: #810/20Do Now Cell Membrane Structure Please complete the Do Now sheet. You may use your notes from yesterday. Do you owe me any late/absent work? Hand it in now!! Did you miss a lab? Fill out a make-up lab request form!!

2 Types of Transport PASSIVE TRANSPORT ACTIVE TRANSPORT

PASSIVE TRANSPORT PASSIVE TRANSPORT movement of molecules through the cell membrane WITHOUT the use of ENERGY

Passive Transport ● The movement is caused by the natural vibration and collision of molecules which causes them to spread out and move through the membrane

CONCENTRATION CONCENTRATION : The amount of a substance (“stuff”) in a given area Low Concentration Equilibrium High Concentration

DIFFUSION Molecules move from where there’s more of them to where there’s less of them (high  low concentration) Uses no energy ALONG concentration gradient

Diffusion (passive transport) 20 g/L 5 g/L12 g/L 13 g/L

Membrane is NOT permeable to: –Starches –Proteins –Salt Osmosis (passive transport) Diffusion of H 2 O Too big Polar Salt = H 2 O = Salt = H 2 O = 90% 70% 30% 10% 85% 15%

Facilitated diffusion Uses NO energy Movement of large molecules across cell membranes through carrier proteins or protein channels

CARRIER PROTEINS/CHANNELS ● Proteins in the cell membrane that move large molecules through the membrane ● Certain carriers/channels allow only specific substances to pass through

Name__________ #_______ 1.Draw a phospholipid. Label the head and the tails. 2.What do we call something that does not like water? 3.What do we call something that does like water? 4.Define “concentration.” 5.How do molecules move in passive transport?

Thursday, October 22, 2015 Do Now: In your TOC (orange)… #910/22Practice Diffusion & Osmosis Begin to work on the Diffusion & Osmosis Worksheet Do you owe me any late/absent work? Hand it in now!! Did you miss a lab? Fill out a make-up lab request form!!

Can things go from low to high concentration? Active Transport movement of molecules from low to high concentration using Energy * AGAINST CONCENTRATION GRADIENT Energy

● This energy is in the form of ATP (Adenosine Triphosphate), which is created in the mitochondria during cellular/aerobic respiration

Cellular Communication:

The cell membrane is scattered with RECEPTOR MOLECULES ● Molecules targeted at a specific cell will bind with the cell surface receptor if the shapes match ● The signaling molecule binds to the receptor and sends a signal that changes the behavior of the cell. ● This is how cells communicate with each other

Friday, October 23, 2015 Do Now: In your TOC (orange)… #1010/23Activity Membrane Structure & Transport Please take out your HW and lab to hand in. Name and number on top! -Begin to work on the front pg. of packet Do you owe me any late/absent work? Hand it in now!! Did you miss a lab? Fill out a make-up lab request form!!