Cellular Transport

Types of Cellular Transport

• Passive Transport cell doesn’t use energy

• Active Transportcell does use energy

high

low

Weeee!!!

high

low

This is gonna be

hard work!!

Passive Transport• cell uses no energy • molecules move randomly• Molecules spread out from an area of high

concentration to an area of low concentration.

• (HighLow)• Three types:

3 Types of Passive Transport

1. Diffusion 2. Facilitative Diffusion –

diffusion with the help of proteins

3. Osmosis – diffusion of water

1. Diffusion

1. Diffusion: random movement of particles from an area of high concentration to an area of low concentration.

(High to Low)• continues until all molecules are

evenly spaced

• Equilibrium = evenly spaced

• Note: molecules will still move around but stay spread out.

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

Simple Diffusion Animation

2. Facilitated diffusion: diffusion of specific particles through proteins found in the membrane – Transports larger or

charged moleculesFacilitated diffusion (Channel Protein)

Diffusion (Lipid

Bilayer)

: 2. Facilitated Diffusion A B

• http://bio.winona.edu/berg/Free.htm

• 3.Osmosis: diffusion of water through a selectively permeable membrane

• Water moves from high to low concentrations

• Water moves freely through pores.

• Solute (green) too large to move across.

Osmosis animation3. Osmosis

Effects of Osmosis on Life

• Water is called the called the "universal solvent" because it dissolves more substances than any other liquid.

• This means that wherever water goes, either through the ground or through our bodies, it takes along valuable chemicals, minerals, and nutrients.

• The substances that are dissolved are called solutes.

How Organisms Deal with Water Pressure

• Paramecium (protist) removing excess water video

• Bacteria and plants have cell walls that prevent them from over-expanding.

• A paramecium that collect water flowing in and pump it out to prevent them from over-expanding.

• Salt water fish pump salt out of their specialized gills so they do not dehydrate.

• Human cells are bathed in blood. Kidneys remove excess salt and water.

Active Transport

• cell uses energy • actively moves molecules to where they are needed

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

•(Low High)• Three Types:

Types of Active Transport

1. Protein Pumps -transport proteins that require energy to do work• Example: Salt Pumps

are important in nerve responses.

Sodium Pumps (Active Transport using proteins)

Protein changes to move molecules: this

requires energy!

• What happens when the material that a cell needs to move into or out of the cell is too big to fit through the cell membrane or a protein?

Types of Active Transport

2. Endocytosis: takes bulky material

into a cell • Cell membrane folds in

around the material• “cell eating”• forms food vacuole &

digests food• This is how white blood cells

eat bacteria!

Types of Active Transport

3. Exocytosis: Forces material out of cell• membrane surrounding the

material fuses with cell membrane

• Cell changes shape – requires energy

• EX: Hormones or wastes released from cell

Endocytosis & Exocytosis

animationsCell membrane

Types of Cellular Transport

• Passive Transport cell doesn’t use energy

1. Diffusion2. Facilitated Diffusion3. Osmosis

• Active Transportcell does use energy

1. Protein Pumps2. Endocytosis3. Exocytosis

high

low

This is gonna

be hard work!!

high

low

Weeee!!!

• Animations of Active Transport & Passive Transport

This powerpoint was kindly donated to www.worldofteaching.com

Modified by Robin O’Connor October 2010