Flashcards in Membrane Deck (31):
Key term describing the structure of the membrane, 2 layers of phospholipids with polar heads on the outside and non-polar tails on the inside.
Phospholipids are classified as?
Phosphoglycerides and sphingolipids
Glycolipids can be classified as?
glycophosphoglycerides and glycosphingolipids
what are the classifications of sterols
cholesterol in animals, phytosterol in plants and hopanoids in bacteria
name the non protein things in the membrane
phospholipids, glycolipids and sterols
describe the structure of a phospholipid
The head group is a phosphate group attached to an R group. The head is connected to the tail with a glycerol. The tail is a fatty acid, either saturated or unsaturated, which can bond to a sterol.
Organisms that live at high temperatures
Organisms that live at room temperatures
organisms that live in low temperatures
The movement of lipids within one layer
the movement of lipids from one layer to the other
An enzyme responsible for flip flopping
proteins imbeded in the membrane. Interact strongly with lipids, require detergents to remove, include enzymes, antigens and receptors.
Integral monotopic proteins
proteins that sit in one layer of the membrane
single pass proteins
a protein that passes once through the membrane
proteins that pass through the membrane multiple times
multiple seperate polypeptides each passing through the membrane
Peripheral membrane proteins
proteins loosely attached to the membrane, easy to remove
covalently bonded to lipids. Classified as fatty acid/prenyl/GPI anchored.
functions of membrane proteins
cell junctions, enzymatic roles, structural roles, transport, sensing and recognising self vs. not self.
The role of carbohydrates in the cell membrane
attach to proteins (glycoproteins) and lipids (glycolipids) to serve as ID tags for identification of self vs. not self
Basically osmosis, requires no energy or special proteins
Equal concentration with in and without the cell, nothing happens
higher concentration of solute outside the cell than in, leads to shrivelling
Higher concentration of solute inside the cell than out, leads to swelling and bursting
diffusion across the membrane in line with the concentration gradient, proteins help overcome the permeability barrier. this requires no energy.
Proteins that allow for passage across the membrane, highly selective
Transport acts against concentration gradient which requires energy. Used for nutrient uptake, waste removal and ion concentration maintenance
2 different compounds going the same way
2 different compounds going in different directions