Exam Specific Flashcards
How does bilayer contribute to stability of plasma membrane?
Contains cholesterol- regulate fluidity
Hydrophobic region- form bilayer
What acts as a barrier to mineral ions?
Phospholipids bilayer
How the structure of phospholipid molecule allow for formation of plasma membranes?
Phosphate head is hydrophilic with water.
Fatty acid tail is hydrophobic
Heads orientate towards water- bilayer form
How does fluid mosaic model describe structure of plasma membrane?
Phospholipid bilayer
Proteins free to move
Proteins scattered randomly
Structure of plasma membrane
Phospholipid bilayer
Cholesterol
Intrinsic and extrinsic proteins
Function of intrinsic protein
Communication across membrane
Allow charged particles to pass through membrane
What is meant by cell signalling?
Lead to a response
Communication between cells.
Width of membrane
7 nm
Roles of membrane at surface
Control of molecules entering
Facilitated diffusion
Cel, recognition
Receptor
AVP
Role of membrane within cell
Compartmentalisation
Site of chemical reaction
Barrier
How do small , non polar substances move out?
Diffuse through phospholipid bilayer.
How do large substances enter plasma membrane.
Carrier proteins
Endocytosis
How do polar substances move to plasma membrane?
Through pores
Carrier proteins
Facilitated diffusion
How do channel proteins work I’m facilitated diffusion
Forms pores
Phospholipid bilayer prevents diffusion
Polar
AVP
Hydrophilic conditions
Protein carrier work in facilitated diffusion or active transport
Attach on one side of membrane
Protein change
Release on other side of membrane
Differences between active transport and facilitated diffusion
Facilitated diffusion does not use ATP, whereas active transport does.
Facilitated diffusion takes place down concentration gradient, active transport takes place down concentration gradient.
Facilitated diffusion uses both channel or carrier proteins, active transport uses only carrier proteins.
Ways substances cross membrane
Osmosis- High WP to low WP gradient
Though channels
Facilitated diffusion- channel/carrier protein, down concentration gradient
Active transport- carrier protein, against concentration gradient, uses ATP
Phagocytosis- engulfing cell membrane to form vesicle
Exocytosis- fusion of vesicles with cell surface membrane
What is Endocytosis?
Membrane folding in
Pinches of/ fuses with itself
Formation of vesicle
Requires energy
Effect of high temperature on Yeast cell membrane
Phospholipid have more kinetic energy
Increase in gps in membrane
Bilayer more fluid
Proteins denatured
Riles of membrane inside cells
Compartmentalisation
Site of attachment for enzymes
Provide selectively permeable membrane
Creation of concentration gradient
