Part 1

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

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? a)Water doesn’t flow at all. b)Water flows from an area of low concentration to an area of high concentration. c)Water flows from an area of high concentration to an area of low concentration.

Lipids Lipids function in: –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 1.Fats (Triglycerides) –G–Glycerol + 3 Fatty Acids –S–Saturated = No Double Bonds (solid) –U–Unsaturated = Double Bonds (liquid) OH Ester Bonds

Egg lab Dissolve egg shells Rinse Calculate initial mass

Lipids 2.Phospholipids –G–Glycerol with Phosphate Head + 2 Fatty Acid Chains –A–Amphiphilic (“Both” “lover”) Hydrophilic head Hydrophobic tail –F–Forms 2 layers in water –M–Makes up cell membranes Organic Compounds: Lipids: Phospholipids Phosphate Glycerol Fatty Acids

phospholipid Membrane proteins Hydrophobic region Hydrophilic heads of phospholipids Carbohydrate side chain Marker Proteins (has carbohydrate side chain attached)

Different Types of Membrane Proteins (page 77) TRANSPORTERSRECEPTORSENZYMES SIGNAL/ RECOGNITION

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

The plasma/cell membrane is selectively permeable ~ It controls what enters and leaves the cell ~ only certain substances are allowed to pass through

What can and can not pass through the membrane? CAN PASS THROUGH Other lipids and fatty substances that dissolve in fat (hydrophobic) Small molecules, like water Things w/o charge CAN NOT PASS THROUGH 1.Water-like substances (hydrophilic) 2.Large molecules 3.Ions: Molecules with plus (+) or minus (-) charges CH 2 OH OH CH 2 OH OH

Go to page 78… Fill in the table… What substances can pass through the membrane?

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 + CH 2 OH OH Passive Transport: Facilitated Diffusion Channel protein

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

Go to page

Now complete page 88 to check your understanding

Endocytosis When cells engulf particles into the cell 2 types 1.Phagocytosis: When a cell wraps part of its membrane around a large particle forming a “pocket” or vesiclePhagocytosis 2.Pinocytosis: The same process, but with smaller particles or liquidsPinocytosis

Exocytosis (opposite of endocytosis) 1.A vesicle carrying a substance 2.fuses with the cell membrane 3.and releases the substance Inside the cell Outside the cell

Check for understanding Complete pages 100 – 101 Section Review