Unit 3 - Cell Transportation

Question 1

Main functions of the cell membrane

Answer 1

• Provides protection to the cell from it’s
  surroundings
• Maintains Homeostasis
• Is semi-permeable to allow materials in or out as needed

Question 2

The phospholipid bilayer

Answer 2

• The Fluid Mosaic Model states that the cell membrane is
  composed of Phospholipids and Proteins
• These are arranged in a Bilayer with Hydrophilic (water
  loving) heads and Hydrophobic (water hating) tails

Question 3

…

Answer 3

Cell membranes help
organisms maintain
homeostasis by
controlling what
substances may enter or
leave cells.
This property is referred
to as selective
permeability

Question 4

How do materials get in and out?

Answer 4

• Proteins allow materials to move in and out of the cell…
• Channel proteins: Form a tunnel
• Carrier Proteins: change shape also called Protein Pumps

Question 5

Transport through cell membranes

Answer 5

• The phospholipid bilayer is a great barrier
  around cells. However, for the cell to
  survive some materials need to be able to
  enter and leave the cell.
• There are 2 main mechanisms:
  1. Passive Transport
  2. Active transport

Question 6

3 types of passive transport

Answer 6

Diffusion, Osmosis, Facilitated Diffusion

Passive Transport is
the movement of a
substance through
the cell’s membrane
without the
expenditure of
ENERGY (ATP)

Question 7

Diffusion: vocab and what effects it

Answer 7

Solute – any substance that
dissolves in water
Ex: Sugars, amino acids and ions
Solvent – the substance that
dissolves the solute
Water is the solvent in cells
Solute + Solvent = Solution
The rate of diffusion depends on:
1. Temperature
2. Size of molecules
3. Type of molecules