Cellular Transport Chapter 7.4

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

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 hill.com/sites/ /student_view0/chapter2/animation__how_ diffusion_works.html hill.com/sites/ /student_view0/chapter2/animation__how_ diffusion_works.html

Passive Transport: Osmosis The diffusion of H 2 0 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 hill.com/sites/ /student_view0/chapter2/animation__how_ osmosis_works.html hill.com/sites/ /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 Diffusion Proteins Integral Peripheral Channel Carrier Marker Receptor Symports Pumps

Facilitated Diffusion How Facilitated Diffusion Works Animation hill.com/sites/ /student_view0/chapter2/animation__how_f acilitated_diffusion_works.html hill.com/sites/ /student_view0/chapter2/animation__how_f acilitated_diffusion_works.html

Solutions SoluteKool Aid Packet SolventWater SolutionKool Aid Drink

Isotonic Solutions

Hypotonic

Hypertonic

Solutions

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.

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.

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