Structure and Function Cell Membrane Structure and Function

FUNCTION OF THE CELL MEMBRANE The cell membrane controls what goes in and out of the cell. Nutrients need to enter the cell If they couldn’t, the cell would die from a lack of energy and building blocks. Wastes need to exit the cell If they couldn’t, cell would become toxic and die.

FLUID MOSAIC MODEL “Fluid”: able to flow and move. Like a soap bubble! “Mosaic”: a composition of many diverse elements Like an artistic mosaic!

Parts of the Cell Membrane Carbohydrates Phospholipid Bilayer Membrane Proteins Outer Surface Cholesterol Cytoplasm

Phospholipid Bilayer Structure Function Made up of a double layer of phospholipids Hydrophilic head & hydrophilic tails Function Provides overall structure for the cell membrane Acts as a barrier between the cell and its surroundings Holds the other components of the cell membrane

Proteins Structure Function Most are embedded in the cell membrane Some are attached to the inside or outside surfaces of the phospholipid bilayer. Function Some transport specific substances in & out of cell Some are enzymes, and control chemical reactions Some receive and transmit signals to other cells in the body

Cholesterol Structure Function Imbedded in the phospholipid bilayer. Helps keep the membrane fluid Lowers fluidity of membrane in high temperatures Increases fluidity of membrane in low temperatures

Carbohydrates Structure Function Cell-cell recognition Attached to proteins or phospholipids on outside of cell. Function Cell-cell recognition Allow other cells to recognize the cell as belonging to the body. Recognize foreign invadors

Apply your Knowledge! Label the following diagram with the terms: Carbohydrate, Phospholipid Bilayer, Cholesterol, Protein, Phospholipid, Hydrophobic tail, Hydrophilic Head

Apply your Knowledge. Complete the following table Apply your Knowledge! Complete the following table. Don’t merely copy from the notes – use your own words in point form. Membrane Component Structure Function Phospholipids Proteins Cholesterol Carbohydrates