how do things move in and out of the cell? transport!

How do things move in and out of the cell?

TRANSPORT!

2 terms used to describe the plasma membrane are:

semi-permeable selectively permeable

Examples:• O2, CO2 (& sometimes H2O) move across the membrane

freely

• (H2O), Ions (charged molecules) and really LARGE molecules need a protein channel to help move across

* Some substances can pass across

them, and others can’t.*

Sugars & Proteins

Pass Freely Protein Channel

can also use the protein channel

Two Types:

1. Simple Diffusion2. Facilitated Diffusion

In BOTH TYPES, small ions and molecules move in/out of the cell

according to the concentration gradient

Passive Transport

Concentration GradientHIGHCONCENTRATION

LOWCONCENTRATION

Certain molecules

(like O2 and CO2 and sometimes H2O) move into/out of the cell according to the

concentration gradient

Simple Diffusion

Diffusion of specific particles through protein channels found in the membrane

Transports larger or charged molecules (ions)

Facilitated Diffusion

Much like the Shape-O toy, Transport Protein channels are specific to certain kinds (shapes) of molecules.

Each hole represents a specific protein channel

The surrounding plastic represents the

lipid bilayer

Facilitated Diffusion

High Concentration

Low Concentration

Cell Membrane

Glucosemolecules

Proteinchannel

Through a Protein channel without needing ENERGY

Channel Proteins animations

Facilitated Diffusion

To a-

From a- High

Low

Diffusion

Facilitated diffusion

(Channel Protein)

H2O

ions

Diffusion (Lipid Bilayer)

O2

CO2

Active TransportMovement across the cell membrane that

requires energy

high

low

This is gonna be

hard work!!

Actively moves molecules to where they are needed

Active TransportDefinition: The movement of material against the concentration gradient.

From an area of low concentration to an area of high concentration

3 Different types:

1. Protein Pump

2. EndocytosisA. PinocytosisB. PhagocytosisC. Receptor-mediated Phagocytosis

3. Exocytosis

Active Transport

Transport Proteins:

move ions against the force of diffusion

Protein Pumps

Show video clip

To do this…Protein changes shape to move the molecules.

Protein Pumps

Show video clip

THIS REQUIRES ENERGY!!!

Protein Pumps

How Does This Happen? Material binds to protein Mitochondria provides

energy that changes the shape of the protein

Change in shape allows material to be moved across membrane

System resets

Protein Pumps

Pumps are used to make neurons work, and for muscle movement

Ex: sodium / potassium pump:

important in nerve responses.

Sodium Potassium Pumps (Active Transport using proteins)

Used for…

1. large molecules

2. clumps of food

3. large amounts of liquid

4. whole cells

Uses energy!(cell membrane folds in on itself)

Endocytosis

Three Types of Endocytosis:

1st Type of Endocytosis: Pinocytosis

A cell engulfs solutes or fluids

“cell drinking”

2nd Type of Endocytosis:

Phagocytosis

A cell engulfs solids/food particles

“cell eating”

Forms food vacuole & digests

This is how white blood cells eat bacteria!

Phagocytosis

Phagocytosis

3rd Type of Endocytosis: Receptor-mediated Phagocytosis

Receptors are

shape specific!

Endocytosisleads to

Exocytosis

ENdocytosis vs. EXocytosisENter EXit

Endocytosis

Exocytosis

membrane surrounding the material fuses with cell membrane

Cell changes shape –

requires energy

Endocytosis & Exocytosis

animations

ExocytosisForces large molecules out of cell

Through exocytosis, the cell…

Excretes wastes

Secretes insulin and other types of hormones into the blood.

Exocytosis

Exocytosis

Vesicle-mediated transport

Exocytosis

Terms to remember

• Semi-permeable (Selectively Permeable) Membrane• Concentration Gradient• Diffusion• Facilitated Diffusion• Active Transport• Protein Pump• Endocytosis• Phagocytosis• Pinocytosis• Receptor-mediated Phagocytosis• Exocytosis

• Membrane has pores or spaces that let small molecules pass right through.

*O2, CO2, (H2O)

• Molecules that are LARGE and/or have a charge (+/-) are blocked.

*Proteins/Na+Cl-/Na+P3-

• Protein pores can control movement of charged ions and larger (but not too large) molecules.

*H2O, Glucose, Amino acids,

Hormones

Summary Factors of Movement

Review General USES of Active Transport…

Protein Pumps: used to make neurons work, and for muscle movement

Endocytosis: White cells digesting bacteria and cell debris

Exocytosis: Secrete insulin and other types of hormones into the blood. Cells get rid of waste!

Key fact: ALL forms of

active transport require . . .

ENERGY!!!

Active Transport

• Animations of Active Transport & Passive Transport

Review of Cellular Transport

Brainpop