Cell TransportPassive and Active Transport

1.All cells have a cell membrane

a.Functions: o Controls what enters and exits

the cello Provides protection and

support for the cell

About Cell Membranes

About Cell Membranes (continued)

2. Structure of cell membrane

a.The cell membrane is made of two layers of phospholipids called the lipid bilayer

b.Proteins are also embedded in cell membrane

Phospholipid

Lipid Bilayer

About Cell Membranes (continued)

3. Cell membranes have pores (holes) in ita. the holes or pores makes the cell

membrane Selectively permeable: or Allows some molecules in and keeps other molecules out

Pores

Outside of cell

Inside of cell (cytoplasm)

Lipid Bilayer

Proteins

Transport Protein Phospholipids

Carbohydratechains

Structure of the Cell Membrane

Go to Section:

Animations of membrane

structure

1. Passive Transport cell doesn’t use energyHIGH low concentrations

2. Active Transportcell does use energyLOW high concentrations

Types of Cell Transport

Passive Transport

Characteristics cell uses no energy molecules move

randomly Molecules spread out

from an area of high concentration to an area of low concentration.

(HighLow)

3 Different Types1. Diffusion2. Facilitated

Diffusion3. Osmosis

Concentration gradient- the difference in concentration of solutes or particles in different places

Concentration Gradient

1. Diffusion1. Diffusion: random movement

of particles from an area of HIGH concentration to an area

of low concentration. Diffusion continues until all

molecules are evenly spaced or have reached equilibrium

http://bio.winona.edu/berg/Free.htm

Simple Diffusion Animation

Facilitated diffusion Facilitated diffusion happens when specific particles move through proteins found in the membrane It is diffusion with the HELP of proteins

in the membrane

2. Facilitated Diffusion

Osmosis Osmosis is ONLY the diffusion of waterwater through a selectively permeable membraneWater moves from high to low high to low concentrations

Osmosis animation3. Osmosis

Solute – a SUBSTANCE dissolved in a fluid

Solvent – the FLUID part of a solution

Solution – a MIXTURE of two or more substances (a solute and solvent)

Solute/Solvent/Solution

This is sugar water.

What is the solute? What is the solvent? What is the whole

mixture called?

Solute/Solvent/Solution

A glass of iced tea.

What is the solute? What is the solvent? What is the whole mixture called?

Solute/Solvent/Solution

Ex: Dr. Pepper

What is the solute(s)? What is the solvent? What is the whole mixture called?

Solute/Solvent/Solution

HypotonicHypotonic: : A solution that has a lot of water and that water moves INSIDE the cell making it swell

Hypotonic Solution• Osmosis

Animations for isotonic, hypertonic,

and hypotonic solutions

Hypertonic: The solution has MORE solutes and a lower concentration of water

The water will move OUT of the cell making it shrink or crenate

Hypertonic Solution• Osmosis

Animations for isotonic, hypertonic,

and hypotonic solutions

shrinks

Isotonic: The concentration of solutes and water in solution and in the cell are EQUAL

Water moves equally in both directions and the cell remains same size!

Isotonic Solution

• Osmosis Animations for

isotonic, hypertonic, and hypotonic

solutions

What type of solution are these cells in?

A CB

Hypertonic Isotonic Hypotonic

Overcoming Osmosis

Contractile vacuoles – structure that will expel excess water from unicellular organisms that live in water. (like Paramecium!)

Turgor pressure – water pressure in a plant cell when a plant is placed in a HYPOtonic solution. A loss of turgor pressure causes wilting (plasmolysis).

Paramecium (protist) removing excess water video

Active Transport

Characteristics • cell uses energy

• actively moves molecules to where they are needed

• Movement from an area of low concentration to an area of high concentration

• Goes AGAINST the concentration gradient

2 Types of Active Transport

1. Endocytosis2. Exocytosis

Types of Active Transport

1. Endocytosis: taking bulky material

into a cell •Uses energy•Cell membrane fold in around food particle•forms food vacuole & digests food•This is how white blood cells eat bacteria!

Types of Active Transport

2. Exocytosis “leaving the cell”

Forces material out of cell in bulk• membrane surrounding

the material fuses with cell membrane

• Cell changes shape – requires energy

• EX: materials or wastes are released from cell

Endocytosis & Exocytosis animations

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