Diffusion, Osmosis, Passive and Active Transport || Biology H

Diffusion (movement)

Movement of molecules from high concentration → low until equilibrium is reached. DOES NOT REQUIRE ENERGY

Cell Membrane main functions:

• Protects the cell

• Controls what enters and leaves

• Maintains homeostasis

What is the cell membrane structure called?

Phospholipid Bilayer

Which one likes water, and which one doesn’t?

Phospholipid Head:
Phospholipid Tail:

Head: Hydrophilic (water-loving)

Tail: Hydrophobic (water-fearing)

Carbs function in a phospholipid bilayer

Helps cells recognize each other (also a protection)

Protein Function in s phospholipid bilayer

Transports molecules

Cell Membranes are, Semipermeable. What does that mean?

They only allow some molecules to pass through. (only allow certain sizes & types of molecules)

What is a Lipid? What are the Key elements?

Long term energy storage, protection, or barrier.

Carbon, Hydrogen, Oxygen (“CHO”)

Chemical structure of a Lipid:

Think Jellyfish

Monomer example:

Polymer Example:

Monomer: Glycerol, Fatty Acid.

Polymer: Lipids

What does a phospholipid look like

What is diffusion? (occurs, type of molecules)

Diffusion occurs for small & uncharged molecules across a semipermeable membrane.

Osmosis is:

The Diffusion of water across a membrane. (but water)

Water: High → Low concentration

Solvent & Solute: Low → High

Hypotonic

Water moves into the cell → swelling.

~ Solute concentration higher (inside cell)

Isotonic

Water moves in and out of the cell, equilibrium.

Hypertonic

Water leaver the cell, causing it to shrink.

Which macromolecules make up a cell membrane?

Carbon Dioxide, Oxygen, Water

Passive transport:

Without energy, Simple Diffusion and Facilitated diffusion

Simple diffusion:

diffusion of molecules across the membrane without protein.

• Oxygen and Carbon Dioxide

Facilitated Diffusion

Diffusion of molecules across membrane with the help of transport protein.

• Water & Glucose

Protein Channel

Passive Transport. Provides an open tunnel through membrane, molecules move across. Choose specific molecules.

Carrier Proteins

Passive and Active transport. Combine and carry molecules. Transport specific molecules.

Active transport (Type of active transport)

Moves molecules against concentration gradient . Low → High.

• ATP/Energy

• Needs a carrier

Endocytosis (Type of active transport)

Large molecules/quantities ENTER the cell

Exocytosis (Type of active transport)

Large molecules/quantities EXIT the cell.