day 14 do now: what happens when you put salt on a slug or a snail? aim: what is osmosis?
DESCRIPTION
Day 14 DO NOW: What happens when you put salt on a slug or a snail? AIM: What is Osmosis?. http://www.youtube.com/watch?v=PiQkebrCw8U. 20 Salt 20 water. 20 Salt 10 water. 10 Salt 20 Water. 10 Salt 10 Water. What is osmosis?. Osmosis is the diffusion of water through a membrane. - PowerPoint PPT PresentationTRANSCRIPT
Day 14DO NOW: What happens when you
put salt on a slug or a snail?
AIM: What is Osmosis?
http://www.youtube.com/watch?v=PiQkebrCw8U
What is osmosis?• Osmosis is the diffusion of water through a
membrane. • Like regular diffusion, water will move from
one concentration to another until both sides are equal in concentration
10 Salt20 Water
20 Salt10 water
20 Salt
20 water
10 Salt
10 Water
How is osmosis different than diffusion?
• In diffusion, the solute (the dissolved material) moves from a high concentration to a low concentration.
• Remember that the solute is small molecules such as glucose, fatty acids, amino acids, oxygen, carbon dioxide and water.
• But because some molecules are too big to get across the membrane, water has to move in toward these large molecules in order to dilute the concentration.
What are the effects of osmosis? (a)
• If the concentration of water inside the cell and outside the cell is the same, there is no net osmosis occurs.
Water goes in
Water goes out
What are the effects of osmosis? (b)
• If the concentration of water is higher outside the cell then inside the cell, the water outside the cell will move inside the cell.
Water goes in (only) Pop!!
What are the effects of osmosis? (c)• If the concentration of water is higher inside
the cell then outside the cell, the water inside the cell will move outside the cell.
Water comes out (only)
How does osmosis affect plant cells?
• All cells goes through osmosis.• Because plant cells have a cell wall
surrounding it, the cell looks differently when osmosis occurs.
If the plant cell is placed in a solution of high concentration of solute……
then the water will leave the cell causing the cytoplasm to shrink.
The cell wall remains the same!!
If the plant cell is placed in a solution of low concentration of solute……
then the water will enter the cell causing the cytoplasm to swell.
The cell wall begins to swell, deforming the shape!!
• http://www.youtube.com/watch?v=rvIh8JvyaYA
Day 15What is Passive and Active
Transport?
DO NOW: How would you define someone who is active? ____________________How would you define someone who is passive? ___________________________
There are 2 ways molecules can get in a cell.
• 1) Passive Transport – This type of transport requires no energy (no ATP). The cell uses the natural process of different concentration and molecule size to help molecules move from one area to another.
How to Remember Passive Transport
Greater Concentration
Lesser Concentration
Examples:
Diffusion
Osmosis
Energy (ATP)
• 2) Active Transport – This type of transport requires energy (ATP) to move molecules across the membrane. Some molecules must go against the concentration grain, therefore they rely on protein “pumps”. To get them across.
There are 2 ways molecules can get in a cell. (cont)
Active transport that requires energy. Movement molecules from low concentration to high.
Greater Concentration
Lesser Concentration
Need Energy (ATP)
How to Remember Active Transport
•Phagocytosis- Movement of large material into the cell. Cell “pinches” the membrane forming a “bubble” around the large material.
Other Type of Active Transport
Why is Cellular Transport Important?
• Cells need materials in order to carry out the 8 life functions• Cells need O2 and glucose to perform respiration•Cells need to get rid of waste products (CO2 & excess water)•Cells need to grow and repair itself•Cells need molecules to break apart and recombine to make new molecules.
•Without cellular transport, cells could not do what they do.
Type of cellular Transport
Energy / No Energy
High to low
Low to high
Special circumstances
Diffusion No energy High to low Small molecules
Osmosis No energy High to low water
Passive Transport
No energy High to low Diffusion/ osmosis
Active Transport Energy (ATP) Low to high Large molecules / cell doesn’t want
Phagocytosis Energy Large particle Cell engulfs large particles
Red Onion in tap water
Red Onion in distilled water starting to rehydrate
Red Onion eventually goes back