IB Biology 1.4

What are the two types of transport?

Active - Requires energy
Passive - Doesn't require energy

How does active transport work?

It goes against the gradient (basically low to high) and requires energy

How does passive transport work?

It goes with the gradient (high to low)

What are the types of passive transport?

Simple diffusion - Transport of small molecules
Osmosis - Movement of water
Facilitated diffusion - Movement of large molecules

What are the types of active transport?

Primary - Direct use of ATP
Secondary - Uses the coupling of one molecule to another to move against amnestying electrochemical gradient

What is diffusion?

It is the net movement of particles across a region of high concentration to low concentration

What influences the rate of diffusion?

Temperature - Kinetic energy
Molecular size - Larger particles are subject to more resistance
Steepness of gradient - The larger the difference between the high and low region, the faster and vice versa

What is osmosis?

The net movement of water across a membrane

What is osmolarity?

It is the measure of solute concentration

What is a hypotonic solution?

The solution in the cell is lesser than outside so the solution rushes in and makes the cell burst

What is a hypertonic solution?

The solution in the cell is greater than outside so the solution rushes out and shrinks the cell

What is an isotonic solution?

Both the inside and outside of the cell have the same concentration

What is facilitated diffusion?

It is the passive movement of solution across a membrane with the help of a protein

What are carrier proteins?

Proteins that change shape to help pass a molecule across a membrane

What are protein channels?

They are proteins that move only along a gradient

What are potassium channels?

They are channels specifically for potassium

How is the energy required for active transport acquired?

ATP
Coupling with another molecule already moving against the gradient (Piggy backing)

What types of proteins are used in active transport?

Carrier proteins

Real world application of active transport

Sodium-potassium pumps in axons of nerves

What are Sodium-Potassium Pumps?

Membrane proteins that pump sodium ions (Na+) out of the cell and potassium ions (K+) into it

What is vesicular transport?

The uses of vesicles to transport molecules in and out of cells

Process of vesicular transport

1. Endoplasmic Reticulum produces and packages proteins to send out into the cell
2. The vessicle is then sent to the Golgi Aparatus and move from the cis to trans side.
3. The vessicle is then sent out to the outside or the lysosome
4. The vessicle then fuses with the plasma membrane and it's contents are expelled

What is bulk transport (endocytosis)?

The temporary breaking of the cell membrane to transport large molecules inside the cell. Requires ATP hyrdrolysis.

What is phagocytosis?

Cell eating

What is pinocytosis?

Cell drinking

What is exocytosis?

The process by which a vessicle fuses with the cell membrane and then releases molecules out of the cell