1

Chapter 3Cell Processes

Section 2: Moving Cellular Material

2

II. Moving Cellular MaterialA. Selectively Permeable Membrane

1. Cells take in food, oxygen, and other substances; they also release waste and Carbon Dioxide CO2.

2. These materials enter and leave through the cell membrane; acts like a screen.

3

II. Moving Cellular Material

3. Selectively Permeable: ability for a substance to allow certain things to pass through and keep other things out.

a. This occurs by the size of the openings in the cell membrane.

4

II. Moving Cellular MaterialB. Passive Transport

1. The movement of substances through the cell membrane WITHOUT the use of energy (ATP).

2. Three types of passive transporta. Diffusionb. Osmosisc. Facilitated Diffusion

5

II. Moving Cellular MaterialC. What is Diffusion? (Passive Transport)

1. Diffusion: random movement of molecules from an area of high concentration to an area of low concentration. (Crowded to Uncrowded)

a. Example: Spraying perfume, adding a drop of food coloring into water.

6

DIFFUSION

7

DIFFUSION

8

II. Moving Cellular MaterialD. What is Equilibrium?

1. When the same number of molecules are on both sides of a membrane.

a. All cells want this but it rarely happens.

9

EQUILIBRIUM

10

II. Moving Cellular MaterialE. Osmosis (Passive Transport)

1. Osmosis is the diffusion of water and only water across a membrane without the use of energy (ATP).

a. Water goes from high concentration to low concentration in diffusion.

b. Crowded to less crowded.

11

II. Moving Cellular MaterialE. Osmosis (Passive Transport)

1. Osmosis is the diffusion of water and only water across a membrane without the use of energy.

a. Water goes from high concentration to low concentration in diffusion.

b. Crowded to less crowded.

12

II. Moving Cellular MaterialF. Cells and Water

1. If a cell is placed into a container of pure water it would keep sucking in the water and would not stop.

a. This will eventually cause the cell to swell to a point of exploding.

2. If a cell is placed in salt water, the cell would get rid of all its water; trying to dilute the salt outside the cell.a. This would cause the cell to shrivel up and die.

13

http://www.biologycorner.com/resources/hypertonic.gif

14

http://www.biologycorner.com/resources/hypotonic.gif

15

http://www.biologycorner.com/resources/isotonic.gif

16

Cells and Water

17

Label: Hypo, Hyper, or Iso!!

18

II. Moving Cellular MaterialG. Facilitated Diffusion

(Passive Trasnport)1. When LARGE

materials need to get into a cell l; from high to low; proteins called TRANSPORT PROTEINS are used to help in this process.

a. Example: Plant roots taking in material for the plant.

19http://w3.uokhsc.edu/human_physiology/presentation/facildiffani.gif

20

II. Moving Cellular MaterialH. Active Transport

1. If energy is needed to get something into or out of a cell ACTIVE TRANSPORT takes place.

2. Active transport is the movement of molecules from an area of low concentration to an area of high concentration with the use of energy (ATP).

a. Cells do not like to do this but it is necessary at times.

b. Transport proteins are needed to do this.

21

22

http://www.sp.uconn.edu/~terry/images/anim/antiport.gif

23

II. Moving Cellular MaterialI. What is Endocytosis? (Active Transport)

1. The process of taking in large substances by surrounding them with the membrane and enclosing them.

24

II. Moving Cellular MaterialJ. Two types of Endocytosis

1. Phagocytosis: large SOLIDS entering the membrane.

a. Amoebas eat this way. b. White blood cells surround germs this way.

25http://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/PhagoAnA.gif

26

II. Moving Cellular MaterialJ. Two types of Endocytosis

2. Pinocytosis: Large liquids entering a membrane.

27

II. Moving Cellular MaterialK. Exocytosis (Active Transport)

1. The releasing of wastes outside the cell. a. This process is the opposite of endocytosis.