1. Moving Cellular Material
2.3

2. Cell Membranes are the protective barriers that all cells have.
It is composed of proteins and phospholipids.
It controls the movement in and out of a cell.
It is semi-permeable and allows materials in and out of the cell.
Cell Membrane

3. The movement of substances through a cell without using the cell’s energy.
Ex. Oxygen and Carbon dioxide use passive transport to enter the cell.
2 types of Passive Transport:
1. Diffusion
2. Osmosis
Passive Transport

4. Passive Transport

5. Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.
Diffusion allows the concentration on both the outside of the cell and the inside of the cell to be equal.
When the amount of substances are equal on both sides of the cell membrane, the substance is in equilibrium.
Diffusion

6. Diffusion

7. Facilitated Diffusion
Large substances are too big to pass through the membrane so it uses special proteins called transport proteins.
Does NOT require energy.
2 Types of Transport Proteins
1. Carrier Proteins – carry large molecules. Ex. Glucose (sugar)
2. Channel Proteins- forms pores through the membrane. Ex. Sodium ions
Facilitated Diffusion

8. Facilitated Diffusion

9. Osmosis is the diffusion of water molecules only thru a membrane.
Water passes through the membrane until equilibrium occurs.
Osmosis

10. Osmosis

11. Is the movement of substances through a cell membrane only using the cell’s energy.
Substances move from an area of low concentration to an area of high concentration.
Is important because cells get the needed nutrients from the environment using active transport.
2 types of Active Transport:
1. Endocytosis
2. Exocytosis
Active Transport

13. Substances that are too large to enter a cell membrane to use diffusion or transport proteins use endocytosis.
The process during which a cell takes in a substance by surrounding it with the cell membrane.
Ex. Bacteria and viruses.
Endocytosis

14. When substances are too large to leave the cell using diffusion or transport proteins use exocytosis.
Is the process during which a cell’s vesicle release their contents outside the cell. Ex. Proteins are removed using exocytosis.
Exocytosis

15. Exocytosis

16. Cell Size and Transport
To release and receive nutrients and wastes, a cell’s membrane must be large.
The surface area of a cell is the are of the cell membrane.
The volume of a cell is the amount of space within a cell.
Surface area to volume ratio:
The volume of a cell increases faster than the area of a cell.
Cell Size and Transport