3.3 Cell Membrane In the top margin of pg 28 or 29: Explain why animal cells cannot undergo photosynthesis. Hint: Look at the difference in organelles.

3.3 Cell Membrane Animal cells lack chloroplasts which is the organelle needed to convert solar energy into energy that the cell can use. Animals cannot make their own food…plants can because they have chloroplasts!

3.3 Cell Membrane Standard 1.a Students know cells are enclosed within a semipermeable membranes that regulate their interaction with their surroundings.

3.3 Cell Membrane Sponge: Set up Cornell Notes on pg. 31 Topic: 3.3 Cell Membrane Essential Question: Explain how membrane receptors transmit messages across the cell membrane Don’t forget to add it to your T.O.Contents! 2.1 Atoms, Ions, and Molecules Explain how membrane receptors transmit messages across the cell membrane 3.3 Cell Membrane Key Concept: The cell membrane is a barrier that separates a cell from the external environment

3.3 Cell Membrane Set up your paper on pg. 30 Divide your paper in to 3 even rows 2.1 Atoms, Ions, and Molecules

3.3 Cell Membrane KEY CONCEPT The cell membrane is a barrier that separates a cell from the external environment. What can we compare this to in our bodies?

3.3 Cell Membrane The cell membrane has two major functions. cell membrane

3.3 Cell Membrane The cell membrane has two major functions. 1. forms a boundary between inside and outside of the cell cell membrane outside cell inside cell

3.3 Cell Membrane The cell membrane has two major functions. 1. forms a boundary between inside and outside of the cell 2. controls passage of materials cell membrane outside cell inside cell

3.3 Cell Membrane Cell membranes are composed of two phospholipid layers.

3.3 Cell Membrane A phospholipid is a molecule composed of three basic parts: –A charged phosphate group –Glycerol –two fatty acid chains *Draw and label this phospholipid on the top of pg 30

3.3 Cell Membrane Head Tail The head is polar interacts with water Hydrophilic Attracted to water The tail is non-polar repelled by water hydrophobic Attracted to other tails

3.3 Cell Membrane cell membrane *Phospholipids arrange themselves like a sandwich into two layers. protein cholesterol protein carbohydrate chain protein channel Contain: Proteins Cholesterol Carbohydrates

3.3 Cell Membrane protein cholesterol protein carbohydrate chain protein channel Pg. 30-middle: draw and label the cell membrane and its parts

3.3 Cell Membrane Fluid mosaic model: Flexible Phospholipids can move from side to side and slide past one another Behaves like a fluid

3.3 Cell Membrane The cell membrane is selectively permeable. Some molecules can cross the membrane while others cannot. *Draw a picture on the bottom of pg. 30

3.3 Cell Membrane The cell membrane is selectively permeable. Some molecules can cross the membrane while others cannot. *Draw a picture on the bottom of pg. 30

3.3 Cell Membrane Receptors are proteins that detect a signal molecule and performs an action in response –It binds with ligands on the outside of the cell –Once they bind, the receptor changes shape and sends a message to the inside of the cell