Part 1

Cell Membrane and Transport

What is an Isotonic Solution? [Water] inside cell = [Water] outside cell Cell is at equilibrium Molecules are equally distributed in end The amount of water entering the cell = the amount of water leaving the cell 95% water 95% water

What is a hypotonic solution? A solution that has MORE water, and LESS solute The cell can lyse or burst if left in a hypotonic solution 100% water 95% water

What is a hypertonic solution? A solution that has LESS water and MORE solute The cell will dehydrate 90% water 95% water

Which direction does water flow? Water doesn’t flow at all. Water flows from an area of low concentration to an area of high concentration. Water flows from an area of high concentration to an area of low concentration.

Lipids Lipids function in: Nonpolar (hydrophobic) Energy (E) storage, forming cell membranes, and as chemical messengers (e.g., hormones) Nonpolar (hydrophobic) Made up mostly of Carbon and Hydrogen (with a few Oxygen)

Lipids Fats (Triglycerides) Glycerol + 3 Fatty Acids Saturated = No Double Bonds (solid) Unsaturated = Double Bonds (liquid) OH OH OH Ester Bonds OH OH OH

Organic Compounds: Lipids: Phospholipids Glycerol with Phosphate Head + 2 Fatty Acid Chains Amphiphilic (“Both” “lover”) Hydrophilic head Hydrophobic tail Forms 2 layers in water Makes up cell membranes Phosphate Glycerol Left-side Activity: Identifying hydrophilic and hydrophobic portions of the membrane. Fatty Acids

Egg lab Dissolve egg shells Rinse Calculate initial mass

The Cell Membrane and Diffusion The plasma/cell membrane is selectively permeable ~only certain substances are allowed to pass through

What can and can not pass through the membrane? CAN PASS THROUGH Things that can dissolve in fat Small molecules Water CAN NOT PASS THROUGH Things that can dissolve in water Large molecules Ions: Molecules with plus (+) or minus (-) charges CH2OH OH

Part 2

Passive Transport 3 types No energy is used There are three types… 3 types No energy is used [High]  [Low] (it’s the natural flow) This means it goes down a concentration gradient

3 types of Passive Transport 1. Diffusion 2. Osmosis 3. Facilitated Diffusion

Diffusion [High]  [Low]

Osmosis

Facilitated Diffusion + Facilitated Diffusion CH2OH OH Passive Transport: Facilitated Diffusion

This means it goes up or against a concentration gradient Active Transport There are three types… 3 types Energy is used [Low]  [High] This means it goes up or against a concentration gradient

3 Examples of Active Transport 1. Protein pumps 2. Endocytosis 3. Exocytosis

Protein Pumps Protein Pumps: proteins use energy to pull or pump materials into or out of the cell to stockpile or store substances the cell needs

Different Types of Membrane Proteins (page 77) SIGNAL/ RECOGNITION TRANSPORTERS RECEPTORS ENZYMES

Different Types of Membrane Proteins (page 77) signal/recognition Enzymes receptor transporter

Endocytosis When cells engulf particles into the cell 2 types Phagocytosis: When a cell wraps part of its membrane around a large particle forming a “pocket” or vesicle Pinocytosis: The same process, but with smaller particles or liquids

Exocytosis A vesicle carrying a substance fuses with the cell membrane and releases the substance