1. Moving Cellular Material
Science 7
Darren Nigh
Cells Chapter 2
Lesson 3 and 4

2. Cells and Spacesuits What do spacesuits and cells have in common?
They both support life
Sometimes in difficult
external environments
What are some similarities
and differences?
Produced 1930’s

3. Spacesuit Features
Strong outer material protection from
space particles
A jetpack to help astronaut
move about
A tank of
compressed provide oxygen
air

4. Cell Features Outer membrane to keep harmful particles out
Tail-like flagella on help cell move
outside of some cells
Tiny openings in cell let oxygen and
membrane water into cell

5. Important Terms Solution
A solute is a type of molecule dissolved in another type of substance; that substance is called a…
Solution
A Solvent is a substance that dissolves the solute

6. CONCENTRATION
Concentration refers to how much of some substance is present, compared to another substance.
For instance, a high solute concentration has a relatively high amount of solute and low amount of solvent.

7. CONCENTRATION EXAMPLES
High solute concentration: lots of sugar dissolved in a relatively small amount of water
Low solute concentration: little sugar dissolved in a relatively high amount of water

8. Diffusion
Diffusion is the process by which a solute passes through pores in a cell membrane
Diffusion also occurs within a specific area (no membrane) as solute
travels from one area of
space to another

9. How do particles move? Fill a beaker with tap water
Add five drops of food coloring to the water
After 10 minutes or so observe what has happened.

10. What happens to color dye dropped into a container of pure water
What happens to color dye dropped into a container of pure water? It disperses evenly!

11. Direction of Diffusion
Molecules ALWAYS diffuse in both directions at once (into and out of a cell)
Net Flow is ALWAYS from greater concentration to lesser concentration

12. What direction will molecules diffuse across this membrane?
What is the net flow?

14. Diffusion in the air Molecules may diffuse through the air environment
Example: aromas

15. Diffusion tendencies - the tendency of molecules to move from a higher concentration to a lower concentration until equilibrium is reached.
Higher concentration
on the left
Equal-Fully diffused
Equalizing

16. What is Osmosis? Osmosis is a form of diffusion.
It is a passive process because it does not require outside energy to start the process.
It is the movement of water molecules Water molecules always flow in both directions at once (into and out of a cell)

17. How does it Work?
The cell is a closed structure protected by its semi permeable bi-lipid membrane.
This membrane will allow certain molecules to enter or leave the cell.
Water will enter or leave the cell based upon its concentration on either side of the cell’s membrane.
Always from higher to lower concentrations

18. Osmosis Animation

19. Osmosis in Plant Cells
The cell wall of a plant will prevent the cell from exploding if placed in a hypertonic solution.
Instead the extra water will push against the wall making the cell stiff or turgid.
Cell Membrane
Cell Wall
Tonoplast
Chloroplast
Nucleus

20. Why Salt Water Fish die in Fresh Water.
The cells of a salt water fish are hypertonic to the fresh water that surround them.
The water will move into the cells causing them to swell and lyse.
The gill and blood cells die, eventually killing the fish.
Atlantic Cod

21. Why a Fresh Water Fish die in Salt Water.
The cells of a freshwater fish are hypotonic to the salt water that surround them.
The water will move out of the cells causing them to shrink or crenate.
The gill and blood cells die, eventually killing the fish.
Black Crappie

22. PASSIVE vs. ACTIVE TRANSPORT
Diffusion and osmosis are examples of passive transport, which occurs without a cell using energy.
Cells can move molecules in the opposite direction across a membrane by utilizing energy. Substances can move from low concentration to high concentration
This is known as active transport.

23. Important Terms Passive Transport Facilitated Diffusion
Movement across a membrane without using energy through diffusion and osmosis from high to low concentration
Facilitated Diffusion
Movement through a cell membrane using special transport proteins.
Carrier proteins move large molecules across the membrane

24. Exocytosis & Endocytosis
For molecules too large to pass through the cell membrane
Cells need to move large molecules. Molecules move into
the cell through endocytosis and out of it through
exocytosis. Both cases, the cell membrane encloses the
molecule in a pocket, pinches off the pocket and moves it
by active transport.

25. Cell size affects transport.
All materials needed by the cell must move through the cell membrane.
If the ratio of volume to surface area is too large and the cell doesn’t change shape there will not be enough membrane area to transport necessary materials into and out of the cell

26. Cells avoid this problem by one of three adaptations:
staying small
dividing
changing shape

27. Lesson 4
Cells and Energy

28. Some cells capture light energy.
Plants capture light energy from the sun through photosynthesis. This process takes place in plant cells that have chloroplasts

29. Plants take water from the soil and carbon dioxide from the air
Plants take water from the soil and carbon dioxide from the air. In chloroplasts a pigment called chlorophyll absorbs light. The cell uses energy to break water into hydrogen and
oxygen

30. The freed hydrogen and the carbon dioxide from the air are combined to make glucose. Most the oxygen from water is released into the air.

31. All cells release energy
All plant and animal cells break down glucose for energy. In cellular respiration the mitochondria in cells convert small glucose molecules into usable energy called ATP.
This process is called Glycolysis
******Oxygen is used during Glycolysis for the releasing of energy for use

32. Fermentation
Fermentation allows cells to release energy without oxygen. It releases small amounts of energy and can produce either carbon dioxide and alcohol or lactic acid.
When you run out of oxygen while exercising, your muscles use fermentation to break down sugar. This results in a lactic-acid buildup, which
makes muscles sore

33. Does Fermentation release any material?
Add 1 packet of yeast to the empty water bottle.
Fill the bottle ¾ full with a sugar solution.
Place the balloon tightly around the mouth of the bottle.
Gently swirl the bottle to mix the yeast and sugar solution
After 20 minutes, observe the balloon.

34. You are now prepared to begin preparation for the Chapter 2 Common Assessment