CELL MEMBRANE

How is the environment connected to the Cells? Video

Review: Remember Chemistry What does polar mean?  Polar means a molecule has a positive and negative end How do polar molecules behave? (“like dissolves like”) Polar molecules attract to other polar molecules Polar molecules do not attract nonpolar molecules.

Basic Structure What do you need to know? Phospholipids arranged in a double layer called a bilayer. Phospholipids are polar molecules. Positive (hydrophilic = water loving) : head Negative (hydrophobic = water hating) : tail

Cell Function What do cells need to get in and out to function properly?  Molecules: CO 2 (Carbon Dioxide) = Nonpolar, small molecule O 2 (Oxygen) = Nonpolar, small molecule H 2 O (Water) = Polar, small molecule C 6 H 12 O 6 (sugars/glucose) = Nonpolar, large molecules Amino Acids (building block of proteins) = typically Nonpolar, large molecules Nucleic Acids (building blocks of DNA) = typically Nonpolar, large molecule Lipids (Called fatty acids) = typically Nonpolar, large molecule Ions = Charged molecules that need to get into or out of the cell

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Jig-saw: Cell Membrane Function 6 ways molecules move 1. Diffusion (p ) 2. Osmosis (p ) 3. Facilitated Diffusion (p. 80) 4. Sodium-Potassium Pump (p ) 5. Endo- & Exocytosis (p. 83) 6. Membrane Receptor Proteins (p ) Assignment: 1. Class number off 1 through ID specific responsibilities based on your number. 3. Read the text  Take notes on what is the important must knows.

Jig-saw: Cell Membrane Function 6 ways molecules move 1. Diffusion (p ) 2. Osmosis (p ) 3. Facilitated Diffusion (p. 80) 4. Sodium-Potassium Pump (p ) 5. Endo- & Exocytosis (p. 83) 6. Membrane Receptor Proteins (p ) Assignment: 4. Get in to groups based on your assigned number. Discuss the must knows from the reading. 5. Each member draw a picture expressing the must knows. “No Words” 6. Plus discuss a real world application of this process.

Jig-saw: Cell Membrane Function 6 ways molecules move 1. Diffusion (p ) 2. Osmosis (p ) 3. Facilitated Diffusion (p. 80) 4. Sodium-Potassium Pump (p ) 5. Endo- & Exocytosis (p. 83) 6. Membrane Receptor Proteins (p ) Assignment: 7. Get into groups with people of your non number. We are going to go with 5 groups. 8. Teacher/student  Each person is responsible for teaching their part.  Everyone is taking notes and copying the illustration.

Lab Experiment 1 1. Fill sandwich bag with 20 mL of Iodine rap rubber band around opening 2. Fill plastic cup w/ 20 mL of Starch solution. 3. Place bag in beaker so opening is outside the beaker 4. Let stand until next class Experiment 2 1. Fill sandwich bag with 20 mL of Starch solution rap rubber band around opening 2. Fill plastic cup w/ 20 mL of Iodine. 3. Place bag in beaker so opening is outside the beaker 4. Let stand until next class Obtain… 1.2 sandwich bags 2.2 plastic cups 3.2 rubber bands

Iodine/Starch Lab Observations  Draw a picture of the before and after for each experiment.  Write a TELL-Con about the experiment.  Answer the questions has evidence. Do both molecules move through the bag? What is it about the structure of a each molecule that determine whether of not it move through the bag? I 2 Starch = Several glucose (C 6 H 12 O 6 ) molecules attached to one another What molecule(s) moves into the bag and why?

What are the keys to getting across the cell membrane?  Size  Polarity  Concentration

Vocabulary that is good to know  Solution  Solute (sugars or salts)  Solvent (water)  Concentration Gradient  If there is a lot of solute = high concentration  If there is little solute = low concentation If you move with the concentration gradient High  Low If you move against the concentration gradient Low  High  When the concentrations are equal we call that equalibrium.

Passive v. Active Transport  Passive Transport  No energy needed  Moves with the concentration gradient  Active Transport  Requires energy  Moves against concentration gradient

Let’s start with Nonpolar, Small molecules Diffusion  Passive Transport  Movement of molecules from a high concentration to a low concentration.  Ex. A Fart!  With the cell membrane diffusion occurs through phospholipids

Let’s talk about water (Nonpolar, small molecules) Osmosis  Passive Transport  Movement of water from a high concentration to a low concentration.  Ex. Bounty paper towel  Water move through the phospholipids

Terms to know about Osmosis  Hypotonic  The lower concentration of solute  Hypertonic  The high concentration of solute  Isotonic  Concentration of solute is equal on both sides Link to Animation hill.com/sites/ /student_view0/chapter2/animation__how_osmosis_works.html

Write TELL-Con on Egg Demo  Use the information learned over the past two slides to answer what happens in the Egg Demo.

Let’s talk about Large molecules moving with concentration gradient Facilitated Diffusion  Passive Transport  Because it is a large molecule it will need an opening to get through. A carrier protein. Link to Animation hill.com/sites/ /student_view0/chapter2/animation__how_facilitate d_diffusion_works.html

Ion Channel Transport Ions (charged molecule)  Passive Transport  Special channel needed to get charged molecules into and out of the cell with the concentration gradient Click Here for Animation

Let’s talk about movement against the concentration gradient.  Active Transport  Needs Energy  Need to know the sodium/potassium Link to Animation imations/ion_pump/ionpump.html

Receptors Proteins Click here for video Form of active transport

Endo- and Exocytosis Passive transport  Endo- = “in”  Exo- = “out”  cyto- = “cell”  -osis = “process” What is Endocytosis? What is Exocytosis? Click here for animation 20Exocytosis.htm

Cell Transport Click here for the video!