Cellular TransportChapter 7.4

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Cell Transportation

• Materials needed for cellular processes must pass into cells so they can be utilized.

• Waste materials from cellular processes must pass out of cells as they are produced.

The Plasma Membrane

• Regulates the passage of material into and out of the cell.

• Depending on the needs of the cell, substances will move either in or out of the cell.

• Because cells exist in a fluid environment, it is possible for substances to move in and out of the cell.

Homeostasis• The necessity of an organism to

maintain a constant or stable condition.

• Dependent on appropriate movement of materials across the cell membrane.

• All organisms have processes and structures which respond to stimuli in ways that keep conditions in their bodies conducive to life.

Homeostasis

• Maintained by the cell membrane.

• The cell membrane is selectively permeable (semipermeable).

• Materials can enter or exit the cell membrane by passive or active transport.

Homeostasis

• How do our cells maintain homeostasis?

• 1)Passive Transport

• 2)Active Transport

http://nestbio.blogspot.com/2010/11/passive-and-active-transport.html

Concentration Gradients

• Molecules move in expected ways based on their concentration gradient.

• At equilibrium, the concentration gradient is the same on both sides, so their is no movement.

Passive Transport• Movement of any substance

through the cell membrane.

• Controlled by the cell membrane.

• Does not require the use of energy.

• Substances move with the concentration gradient.

• HIGH TO LOW GO WITH THE FLOW

• Process by which molecules spread across a cell membrane to reach an equal concentration (equilibrium).

• Slow process dependent on concentration, temperature, and pressure.

• Movement of small ions, atoms, gases, and molecules.

• HIGH TO LOW GO WITH THE FLOW

Passive Transport:Diffusion

Diffusion

• How Diffusion Works Animation

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_diffusion_works.html

Passive Transport:Osmosis

• The diffusion of H20 through a selectively permeable membrane.

• Water will move in and out of the cell until it reaches equilibrium.

• Dependent on the concentration gradient.

• HIGH TO LOW GO WITH THE FLOW

Osmosis

• How Osmosis Works Animation http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

Passive Transport:Facilitated Diffusion

• Substances that are not able to pass directly through the cell are able to enter the cell with the aid of transport proteins.

• Occurs along a concentration gradient.

• Ex) Glucose

Facilitated DiffusionProteins

• Integral

• Peripheral

• Channel

• Carrier

• Marker

• Receptor

• Symports

• Pumpshttp://www.clker.com/clipart-49540.html

Facilitated Diffusion

• How Facilitated Diffusion Works Animation http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_facilitated_diffusion_works.html

Solutions

SoluteKool Aid Packet

Solvent Water

SolutionKool Aid Drink

Isotonic Solutions

http://imcurious.wikispaces.com/Midterm+Exam+2010+Review+P2

Hypotonic

http://spmbiology403.blogspot.com/2008/08/types-of-solution-hypotonic.html

Hypertonic

http://spmbiology403.blogspot.com/2008/08/types-of-solution-hypertonic.html

Solutions

http://biologyforlife.wordpress.com/2011/03/25/3-2-the-movement-of-substances-across-the-plasma-menbrane-in-everyday-life/

Active Transport• Cells pump molecules through the cell

membrane and require energy.

• Molecules move across the cell membrane against the concentration gradient (low to high).

• Cells use this process to concentrate molecules within the cell or to remove waste from the cell.

• Ex) Calcium, Sodium, and Potassium ions

Active Transport:Proton Pump

• Causes production of ATP molecules (energy).

• Actively transports proteins through the membranes of mitochondria and chloroplasts.

http://bioap.wikispaces.com/Ch+7+Collaboration+2010

Active Transport:Na+/K+ Pump

• Uses ATP to transport Na and K into and out of the cell.

• Nerve cells use the difference in ion concentrations to send signals throughout your body.

http://163.16.28.248/bio/activelearner/05/ch5c4.html

Active Transport:Endocytosis and Exocytosis• When molecules are too large to

pass through the cell membrane, the use of vesicles is required.

• If the large molecule is passing into the cell it is called endocytosis.

• If the large molecule is passing out of the cell it is called exocytosis.

Endocytosis and Exocytosis

http://thescienceupdate.blogspot.com/2010/09/may-force-be-with-you.html