Cell Membrane SC.912.L.14.2 Relate structure to function for the components of plant and animal cells. Explain the role of cell membranes as a highly selective barrier (passive and active transport)

Cell Membrane Objective: Describe the structure of the cell membrane and explain how it contributes to its function EQ: How is the structure of the cell membrane related to its function? How is the structure of the cell membrane related to its function?

Turn and Talk You’re one of the main characters in The Walking Dead zombie apocalypse. You’re trying to find somewhere protected to stay long-term. What are some things you’d need to consider about the type of shelter you need?

Cell Membrane Structre Cell membranes are made of phospholipids, a type of lipid that has a polar phosphate head and two fatty acid tails Which part of this molecule would be attracted to water? Why?

Cell Membrane: Structure Phosphate Head Fatty Acid Tails The polar phosphate head is hydrophilic (water loving) the tails are nonpolar and hydrophobic (water hating). What does it mean to be polar?

Check for Understanding Why is the arrangement of phospholipids in the membrane called a bilayer? The prefix bi means two; since there are two layers of phospholipids, it is called a bilayer Which part of the phospholipid would be on the outside?

Cell Membrane Structure The phospholipids form a bilayer with the hydrophobic tails inside, protected from the water

Stop and think Think about the structure of the CM, what material do you think will pass through easily? Why?

Selective Permeability Cell membranes are selectively permeable, some materials can pass through the membrane while others cannot

Parts of the Membrane the cell membrane also contains proteins, carbohydrates, and cholesterol All of the molecules are in constant motion, sliding past one another. This is called the fluid mosaic model. cell membrane protein cholesterol carbohydrate chain protein channel Fluid because they ripple and move if your poke the cell.

Parts of the Membrane: Channel Protein provide places for molecules to move across the membrane (either into or out of the cell) Ex: Like tunnels/ channels

Parts of Cell Membrane: Cholesterol helps provide strength to the cell membrane Ex: structural support

Parts of Cell Membrane: Carbohydrates help identify and distinguish the cell from other types of cells Ex: state flags in the U.S.

MAIN Part of Cell Membrane: Phospholipid creates barrier around cell with the hydrophobic tails facing in and the hydrophilic heads facing out Ex: security

Cell Membrane: Function There are two main functions of the cell membrane: Protects from outside environment - forms boundary between the inside and outside of the cell Controls what enters and exits the cell – because it is semi-permeable

Think, Pair, Share Why might it be important for a cell to regulate the materials moving into and out of it? Conditions outside the cell are constantly changing. However, a cell must maintain homeostasis to carry out its functions. To do this, it must be able to control the movement of particular molecules across the cell membrane.

H- work with your partner Build a Membrane C – level 2 voice H- work with your partner A- build a model membrane out of the materials provided M- remain seated in your assigned seat P- complete your activity sheet with justrifications Success! Working with a partner, build a membrane out of the materials provided.

Exit Ticket Clear you desk of everything except something to write with!