Forces acting across the membrane Flashcards
What happens during endocytosis?
Invagination of membrane to form a vesicle around the target substance
Which type of membrane protein can be removed without major disruption?
Peripheral
What is dystrophin an example of?
Peripheral membrane protein
What is the basic structure of the membrane?
Phospholipid bilayer
What permeability of the membrane layer?
Selectively permeable
Why is the membrane flexible?
Due to fatty acids
What are the two classes of membrane proteins?
Integral Membrane Proteins
Peripheral proteins
Which type of membrane protein cannot be removed without disrupting the membrane?
Integral membrane proteins
Diffusion is aided by what?
Large surface area
High permeability
High conc. gradient
What do molecules need to be to diffuse through the lipid bilayer?
Small
Uncharged
Hydrophobic (lipophilic)
Name the two “gated” channels?
Voltage-gated
Ligand-gated
Give an example of a voltage-gated channel
Na+ channels in nerve cells
What is the name given to a membrane potential that can affect the diffusion of ions across the membrane?
An electrochemical gradient
What do membranes provide binding sites for?
Chemical recognition
E.g. hormones
Which protein channel is effected by the changes in electrical potential?
Voltage-Gated
What are the 2 types of carrier mediated transport system?
Facilitated Diffusion
Active Transport
Why does active transport require energy?
To move substances against the gradient
What does osmolarity measure?
The number of osmoles of solute per litre of solution
When a cell is placed in a hypertonic solution, the cell will?
Shrink
When a cell is placed in a hypotonic solution, the cell will?
Swell and possibly burst
