Cell Boundaries Biology Ms. Lew

Vocabulary Hypertonic Active Transport Hypotonic Diffusion Isotonic Osmosis Phagocytosis Phospholipid Pinocytosis Semipermeable Active Transport Diffusion Endocytosis Exocytosis Facilitated Diffusion Hydrophilic Hydrophobic

to regulate movement of molecules into/out of a cell Cell Membranes One of the most important functions of a cell membrane: to regulate movement of molecules into/out of a cell

A cell membrane is said to be __________________________ Which means only specific kinds of molecules can get through the membrane Another word for it is ______________________ Selectively Permeable Semipermeable

Label the diagram of a cell membrane shown below: Outside of cell Carbohydrate chains Proteins Cell membrane Inside of cell (cytoplasm) Protein channel Lipid bilayer

3. Selectively Permeable Cell membranes let some molecules enter a cell, but prevents other molecules from getting in. Can Enter Can Not Enter - Water - Small Molecules (O2 & CO2) - Non-polar lipids - Macromolecules - Ions (Na+,Cl-) - Hydrophilic molecules (glucose)

The more solute per volume equals a greater concentration. The concentration of a solution is: The mass of the SOLUTE divided by the volume of the SOLUTION For example: 10g/1L The more solute per volume equals a greater concentration.

6. Diffusion The movement of molecules from an area of high concentration to an area of lower concentration Spray and food color demo

Example of Diffusion: Beaker of water. Add salt to the water. Will all of the water be salty or just the side of the beaker that you dumped the salt into? When you add salt the salt will diffuse to all of the water.

Figure 7-15 Osmosis

Figure 7-15 Osmosis

Example of Diffusion: The smell of popcorn after it’s been popped. Does the smell of popcorn stay where the popcorn was popped? Why or why not?

Diffusion http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

Osmosis The diffusion of water. The movement of water from a high water concentration to a low water concentration.

Osmosis http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

3 types of solutions - Hypertonic - Hypotonic - Isotonic

Hypertonic Solution has a higher solute concentration than the cell. There’s more water concentration inside cell… SO, - Water leaves the cell - Animal cells shrink

Hypotonic Solution has a lower solute concentration than the cell. There’s more water concentration outside the cell… SO, Water enters the cell Animal cells expand and possibly burst

c. Isotonic The concentration of the solutes is the same inside and outside the cell. Water goes in and out at the same rate and pressure doesn’t change

Types of Diffusion across a membrane

Facilitated Diffusion The movement of specific molecules across cell membranes through protein channels.

Facilitated Diffusion http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html

Active Transport Energy requiring process that moves material across a cell membrane against a concentration difference.

Active Transport http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html

Facilitated diffusion 20. Complete the following chart to compare types of movement through a cell membrane: Types of molecules transported Special channel required? Energy reguired? Diffusion Osmosis Facilitated diffusion Active transport no no Small molecules water no no ions, sugars (glucose), salts yes no ions (H+, K+, Na+, Ca2+) yes yes

Overview

Movement of materials to/from membrane

Endocytosis: Taking material in to the cell through cell membrane pockets ie. Phagocytosis: Solids or large molecules moved ie. Pinocytosis: Liquids moved

Exocytosis: Releasing material from the cell