part 1. what is an isotonic solution? [water] inside cell = [water] outside cell cell is at...
TRANSCRIPT
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
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 dehydrate90% 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.
Lipids2. 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
Organic Compounds: Lipids: Phospholipids
Phosphate
Glycerol
Fatty Acids
phospholipid Membraneproteins
Hydrophobicregion
Hydrophilic heads of phospholipids
Carbohydrate side chain
MarkerProteins (has carbohydrate side chain attached)
Different Types of Membrane Proteins (page 77)
TRANSPORTERS RECEPTORS ENZYMESSIGNAL/ 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
CH2OH
OH
CH2OH
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. Diffusion2. Osmosis3. Facilitated Diffusion
Diffusion
[High] [Low]
Osmosis
Facilitated Diffusion+ CH2OH
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 pumps2. Endocytosis3. 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
Go to page 87 - 88
8
2
1
6
7
4
3
5
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 arounda large particle forming a “pocket” or vesicle
2. Pinocytosis: The same process, but with smaller particles or liquids
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