Transport Across Cell Membranes Flashcards
What are the main functions of plasma membranes?
Forms boundary between 2 environments (compartmentalisation) allows different condition in either side of membrane
Partially permeable barrier so controls movement of substances in and out
What are plasma membranes made of?
2 layers of phospholipids: phospholipid bilayer
Cholesterol
Peripheral (extrinsic) proteins
Integral (intrinsic) proteins
Sugar side chains
What are the types of membrane proteins?
Transporter, receptor, enzyme and anchor
What are the types of transporter proteins?
Carrier and channel
What can cross the phospholipid bilayer?
Lipid soluble (non-polar) substances
Small molecules eg. H2O
What cannot cross the phospholipid bilayer?
Most water soluble (polar) substances
What does isotonic mean?
Same water potential
What does hypertonic mean
Low water potential (high concentration of solute)
What does hypotonic mean?
High water potential (low solute concentration)
In plants, what happens when the area surrounding cell is isotonic?
Incipient plasmolysis
In animals, what happens when the area surrounding cell is isotonic
Normal
In plants, what happens when the area surrounding cell is hypertonic?
Plasmolysis
In animals, what happens when the area surrounding cell is hypertonic?
Shrivelled
In plants, what happens when the area surrounding cell is hypotonic?
Turgid
In animals, what happens when the area surrounding cell is hypotonic?
Lysed
