7 3 cell boundaries copy

Unit 3: Cells

Chapter 7: Cell Structure & Function

7-3: Cell Boundaries

Ms. PetrucciBiology

Cell Boundaries

Cell Wall

• Provides support and protection for the cell.

• Made from carbohydrate and protein fibers.

• Found in plants, algae, fungi and many prokaryotes.

• Cellulose

Cell Membrane

http://www.youtube.com/watch?v=moPJkCbKjBs

Plasma Membrane

• AKA Plasma membrane

• Protective barrier between the cytoplasm and the outside environment that provides support to the cell.

• Controls everything that goes into and out of the cell.

• Selectively permeable/ semipermeable

Phospholipid Structure• Composed of

phospholipids (fatty acids and alcohols)

• Phospholipids contain a phosphate group

• Bilayer – arranged in 2 layers

Other Molecules in the Membrane

• Proteins (integral and peripheral)– Channels

– Pumps

• Lipids– Cholesterol (animal cell

membranes only)

• Carbohydrates– Attached to proteins– Chemical identification

cards

Types of Membrane Proteins

http://education-portal.com/academy/lesson/membrane-proteins-functions-types tructure.html#lesson

Diffusion Through Cell Boundaries

• Movement of molecules from one side of the membrane to the other is an important functions of the cell membrane.

• Recall from Chapter 2:– What is a solution?– What is a Solute?– What is a Solvent?

• The CONCENTRATION of a solution is the mass of solute in a given volume of solution.

Lets look at Concentration

Diffusion

• What is diffusion?

Simple Diffusion

Facilitated Diffusion

Osmosis

http://lh5.ggpht.com/-NszBjuqRNSM/Uor7263L-RI/AAAAAAAAAZ0/CBsGMDs5FHE/s1600/osmosis%25255B4%25255D.gif

The movement of water molecules

through a semipermeable membrane rom

the region of higher water

concentration to the region of lesser water

concentration

Osmosis

https://www.youtube.com/watch?v=w3_8FSrqc-I

Osmotic Pressure

Osmotic Pressure

https://www.youtube.com/watch?v=yguSfhiTIfY

Active Transport

ATP

Sodium-Potassium Pump

Vesicle Transport

Endocytosis in Animal Cells

Exocytosis

Homeostasis and Cell Function