Cellular Transport Active vs Passive Cellular Transport Essential

Cellular Transport Active vs. Passive

Cellular Transport Essential Question. • How and why is the plasma membrane (structure & function) essential in maintaining the homeostasis for the cell in reference to transport, hypertonic solutions, hypotonic solutions, and isotonic solutions?

Activating Strategy! Scenario Strawberries with sugar. Raisins in water. Predict the Outcome Observed Outcome

Plasma/Cell Membrane • Surrounds and contains the cell’s contents • Controls what enters or leaves the cell • Double layer of phospholipids & proteins

Lipids of Cell Membrane • Membrane consists primarily of phospholipids – phospholipid bilayer inside cell phosphate hydrophilic lipid hydrophobic outside cell

The Fluidity of Membranes • Phospholipids in the membrane are fluid – like (meaning they can move easily) Lateral movement (~107 times per second) (a) Movement of phospholipids Figure 7. 5 A Flip-flop (~ once per month)

Semi-permeable membrane • Will allow passage through the membrane • However, it needs to control what gets in or out – membrane is semi-permeable sugar aa lipid H 2 O salt NH 3 So how does a semi-permeable membrane work? Pair and Share! Explain what happened in the Activating Strategy.

Hypertonic, Hypotonic, & Isotonic

Type of solution What is it Which way will water move What happens to a cell placed in the solution? Hypertonic More solute outside the cell than inside the cell Outside the cell Shrink Hypotonic More solute inside the cell than outside the cell Inside the cell Swell Isotonic Equal concentration of solutes inside and outside the cell Movement of water is equal nothing

Movement of water • What will happen to a cell that is too hypertonic? – The cell will shrink • What will happen to a cell that is too hypotonic? – The cell will burst!

Transport • What does transport mean? – The movement of something • How many kinds are there? – 2 • What are they called? – Passive transport and active transport

Passive Transport • Definition: Movement of particles through the plasma membrane with no energy • Particles move down the concentration gradient • What does this mean? – Particles move from an area of high concentration to low concentration *(think of the tennis ball example)

Facilitated Diffusion • Definition: passive transport of materials across the membrane using transport proteins • Channel proteins: form channels allowing specific molecules to flow through • Carrier proteins: change shape to allow a substance to pass through the plasma membrane

Channel Proteins Permit the passive movement of molecules or ions of appropriate size (dialysis) through an aqueous pore

Carrier Proteins Bind to specific solutes to transport them across a membrane. Examples can be facilitated diffusion (passive) or pumps (active), like a sodium-potassium pump.

Time Out! From memory fill out Facilitated Diffusion

Specialized Passive Transport • The movement of any molecule across a selectively permeable membrane with the concentration gradient is referred to as Diffusion. • The movement of H 20 across a selectively permeable membrane with the concentration gradient is referred to as Osmosis.

Time Out! Pair & Share: 1’s Simple Diffusion & 2’s Osmosis.

Active Transport • Definition: Movement of particles through a membrane against a concentration gradient • ***REQUIRES ENERGY!!!! ***: O • Which way do particles move? ? – LOW concentration to HIGH concentration

Active Transport • Uses carrier proteins to move particles against the concentration gradient

Time Out! From memory fill out Active Transport!

Passive vs. Active transport Type of transport Transport protein used Direction of movement Requires energy input from cell? Classification of transport Simple diffusion No Down the concentration gradient No Passive Facilitated diffusion Yes-channel and/or carrier proteins Down the concentration gradient No Passive Active transport Yes-carrier proteins Against the concentration gradient yes Active

Transport of large particles • Endocytosis: Cell surrounds and takes in material from the environment (Enters) • Exocytosis: Cell expels (releases) material from a cell (usually to remove wastes) (Exits)

Time Out! Pair & Share: 1’s Active Transport & 2’s Passive Transport. Then work together to complete similarities.