Membrane Function Flashcards
(24 cards)
What are membranes fully permeable to?
Hydrocarbons, O2 and CO2
What controls entry of substances into the cell?
Proteins.
What are the modes of transport?
Passive and active transport.
What is Tonicity?
The ability of an extracellular fluid to influence the uptake of water into a cell
What does isotonic mean?
The conc is equal inside and outside of cell. An equilibrium position has been reached.
If an animal cell becomes very hypotonic, what will happen?
It will burst.
Plant cells are usually in what state?
Hypotonic.
What is the name for the process of an animal cell when it shrinks through hypertonicity?
Crenation.
If a plant cell is hypertonic, what happens to it, what is this called?
Plasmolysed, the cell membrane shrinks away from the cell wall.
If a protein requires the use of a protein to be diffused across a membrane, what is it called?
Facilitated diffusion.
Is facilitated diffusion passive or active transport?
Passive.
What lines ion channels.
H2O molecules and Hydrophilic amino acids.
Ion channels that are open all he time are responsible for?
Stabilising the membrane potential.
What is the membrane potential?
The difference in voltage charge across membrane
What happens if membrane potential changes?
The gate to the ion channel opens/closes.
Where is Na+/K+ conc higher?
Na+ is higher outside cell
K+ is lower outside cell
What does the conformational change caused by phosphorylation create?
2 K+ binding sites
How does the asymmetric charge presented by membrane potentials arise?
Electrogenic pumps. Pump ions across the membrane.
What can membrane potentials be used to do?
Transport other secondary solutes
What does the movement of charged solutes depend on?
Concentration of solute and Charge of solute
What do electrogenic pumps create?
An asymmetric distribution of ions, which provides a store of potential energy.
How many types of endocytosis are there? What are they?
Receptor mediated endocytosis, Pinocytosis And phagocytosis
When a vesicles containing nutrients for the cell approaches the cell, what happens in order for the vesicle to be taken up by the cell.
Endocytosis, the lipids of the vehicle’s PM merge with the lipids of the Cell’s PM.
What are the types of exocytosis?
Regulated release via signals
Constitutive release
