1. CELL MEMBRANE AND CELL TRANSPORT NOTES

2. CA Standard Cell Biology
1. a. Students know cells are enclosed within semipermeable membranes that regulate their interaction with their surroundings.

3. What is the cell membrane?
The cell membrane regulates what enters and leaves the cell and also provides protection and support.

4. The structure of the cell membrane
The cell membrane consists of a lipid bilayer (lipid = fat; bi=2) plus proteins that straddle the bilayer. Attached to the proteins are carbohydrates.
Many of these proteins are channels and pumps that allow substances through or not!

5. Draw the cell membrane, color and label it. (p.182)

6. Cell Membrane

7. You should be able to answer these questions:
Describe the structure of the cell membrane.
How do molecules get into and out of the cell?
What is selective permeability?
What is diffusion and how does it work?
What is facilitated diffusion and how does it work?
What is active transport and how does it work?
What is osmosis and how does it work?
What is the function of transport proteins?

8. Transport through the Cell Membrane

9. Cell membranes are selectively permeable (semipermeable).
Permeable- ability to pass through a membrane
Impermeable- can’t pass through
Selectively Permeable (semipermeable)- some things can pass through and some can’t

10. Copy the chart into your notes
Type of
Transport
Transport Protein Used?
Direction of movement
Requires Energy input from cell?
Classification of transport?
Types of Substances
Simple Diffusion
Facilitated Diffusion
Active Transport

11. Transport Through the Membrane
Simple
Diffusion
Facilitated
Active
Transport

12. Simple Diffusion No transport protein used
Movement WITH the concentration gradient
(high to low)
No additional cell energy required
PASSIVE
Examples: water, carbon dioxide and oxygen

13. Requires Energy input from cell?
Type of
Transport
Transport Protein Used?
Direction of movement
Requires Energy input from cell?
Classification of transport?
Types of Substances
Simple
Diffusion NO
With concentration
gradient
(high to low)
PASSIVE
WATER,
CO2, O2
Facilitated
Active

14. Solution- a liquid with one or more substances dissolved in it
Solvent- the liquid that the solute is dissolved in
Solute- the substance dissolved in a solution
Concentration- how strong it is  the solute/volume (percentage)

15. Think of living cells like little bags of solutions surrounded by a semipermeable membrane! For the cell to survive, the concentration of solutes must stay within a safe range to maintain homeostasis.

16. Concentration Gradient- when there is a difference in concentrations
High concentration: more particles
Low concentration: fewer particles
In diffusion, particles move from high to low concentration to reach an equal concentration (equilibrium) on each side.

19. Facilitated Diffusion
Transport protein used: carrier protein or channel protein
Movement WITH the concentration gradient (high to low)
No additional cell energy required
PASSIVE
Example: Glucose molecules

20. Requires Energy input from cell?
Type of
Transport
Transport Protein Used?
Direction of movement
Requires Energy input from cell?
Classification of transport?
Types of Substances
Simple
Diffusion NO
With concent.
gradient
PASSIVE
WATER,
CO2, O2
Facilitated
Yes: Channel Proteins or Carrier Proteins
With concent. gradient
GLUCOSE
Active

21. Carrier Proteins

22. Channel Proteins

23. Passive Transport: Facilitated Diffusion

24. Active Transport Transport protein used: carrier protein
Movement AGAINST the concentration gradient (low to high)
Additional cell energy required
ACTIVE
Example: Sodium-Potassium Pump: pumps Na+ ions out of cell and K+ ions into cell

25. Requires Energy input from cell?
Type of
Transport
Transport Protein Used?
Direction of movement
Requires Energy input from cell?
Classification of transport?
Type of Substance
Simple
Diffusion NO
With concent.
gradient
PASSIVE
WATER,
CO2, O2
Facilitated
Yes: Channel Proteins or Carrier Proteins
With concent. gradient
GLUCOSE
Active Transport
Yes: Carrier Proteins
Against concent. gradient
YES
ACTIVE
Na+ and
K+ ions

26. Active Transport

27. Active Transport

29. Other Types of Active Transport
Endocytosis – the process of taking material into the cell by folding in pockets of the cell membrane into pouches called vesicles
Phagocytosis – endocytosis involving large solid particles
Pinocytosis – endocytosis involving liquid
Exocytosis – the process of removing material out of the cell where vesicles merge with the cell membrane to release contents

30. Endocytosis and Exocytosis

31. Osmosis- the diffusion of water
No transport protein used
With the concentration gradient (high to low)
No additional cell energy required
Passive

32. Concentration Strength
Isotonic – the solution and the cell have the same concentration strength
Hypotonic – the solution has a lower concentration than the cell
Hypertonic – the solution has a higher concentration strength than the cell

33. Osmotic Pressure
Osmotic Pressure is the pressure that water exerts on the hypertonic side of a selectively permeable membrane.
It can be problematic for living cells because they can burst from over-inflation with water or shrivel up from loss of water.

35. Red Blood Cells in a Hypertonic Solution

37. Plants and Osmosis

38. Applications of Osmosis
Water overdose/intoxication
Penicillin kills bacteria
High concentration of fertilizer kills plants
Water enters the roots of plants
Why drinking salt water can kill you
Why putting salt on a slug or snail kills it
How dialysis machines work
The preservation of foods in salt brines (olives, fish vegetables)  kills bacteria
Desalination works by reverse osmosis
Refresh wilted salad greens by putting in water

39. Osmosis Worksheet 10 points

40. Diffusion and Osmosis in Living Systems 40 pts

41. Cell Quiz What are two differences between prokaryotes and eukaryotes?
An animal cell is a prokaryotic/eukaryotic cell. (circle the correct answer)
When preparing a wet mount, the cover slip should be put on at an angle to avoid ______.
The ______ contains the DNA and controls the cell.
Diffusion is the movement of molecules from a ______ to a _______ concentration.
If a cell has 95% water and it is placed in a hypertonic solution, water will move out of/into the cell. (circle the correct answer)
_________ are where photosynthesis occurs in plant cells.
A bacteria is a prokaryotic/eukaryotic cell. (circle the correct answer)
On high power, more/less of the cell can be seen. circle the correct answer)
What two things happen to an image when viewed under a microscope?
Choose and explain one of the following: endocytosis, phagocytosis, pinocytosis, or exocytosis.