Biological Membranes Flashcards
(16 cards)
Describe fluid mosaic model
Phosolipid bilayer with protein molecules are scattered throughout. Some proteins have carbohydrates attached these are glycoproteins which some have lipid attached called glucolipids. Cholesterol are present in bilayer
What does hydrophilic mean?
Attracts water such as the head of phosolipids
What is the function on a membrane?
Acts as a barrier between cell and its environment. Controls what substance come in and out as there partially permeable.
Factors effecting membrane permeability:
Solevents
Temperature
What is cell signaling?
A messager molecule such as a hormone travels to another cell (eg the blood). Once cell defects cell it binds to receptors on its membrane triggering a change in cell
What is glucagon?
Hormone that released she isn’t enough glucose in the blood. Binds to liver cell receptors causing break down on of glycogen stores
How do molecules pass through the membrane
Diffusion ( facilitied)
Factors effecting rate of diffusion
Concentration gradient
Thickness of exchange surface
Surface area
Temperature
What is osmosis?
The diffusion of water molecules across a partially permeable membrane down a water potential gradient. High water potential to low water potential.
What is a hypertonic solution?
Solution wotch a Lowe water potential that cell so net water movement is out.
Why can’t somd molecules pass through membrane?
To large
Polar
What’s an agnostic?
A drug which mimics a molecule such as morphine.
Describe Anatgostis
Stops the signals having an affect such as beta blockers
Examples of active transport.
Uptake of glucose and amino acids in small intestine
Absorption on mineral ions in plants roots
Excretion by hydrogen ions and urea by kidneys
Exchange of sodium and potassium ions in nuerons and muscle cells
What are the types of membrane receptors?
G protien coupled receptors
Ligand gated ion channel
What is the movement of water out of cells called?
Hypertonic
