Cell membranes Flashcards
What does membranes being fluid mean?
lipids and proteins can diffuse rapidly
What is hydrophobic property of fatty acid?
Saturated or unsaturated carbon chain
What are membrane lipids?
phospholipid
glycolipids
cholesterol
What is phospholipid made of
2 fatty acid + glycerol + phosphate + alcohol
Where is ester bond in PPL?
between phosphate and alcohol
What is polar head?
outside since it is hydrophillic
What are lipid bilayers held together by?
non covalent hydrophobic interactions
What does hydrophobic fatty acid chains mean?
lipids close and form compartments
lipid bilayers are self sealing
What are integral membrane proteins ?
transverse the bilayer
What are Peripheral membrane proteins?
bind to outer surfaces of integral proteins
What does bacteriorhodopsin consist of?
alpha helices, amino acids in helices are non polar
What is Bacterial porin consist of?
anti parallel beta strands bonded via H bonds
what is bacterial porin?
outer membrane protein for pores or channels
what is bacteriorhodopsin ?
proton pump
What is the enzyme Prostaglandin H2 synthase held in the membrane by?
alpha helices with hydrophobic side chains
What does table of free energy change for amino acids being transferred from hydrophobic to aqueous show?
amino acids more negative value= in aqueous environment
how wide is hydrophobic core of membrane?
30A
What does fluid mosaic model of PPL bilayer allow?
Lateral movement
What is transverse diffusion?
from one membrane surface to the other
What controls membrane fluidity?
- double bonds and length of fatty acid chain
- cholesterol content
What do unsaturated fatty acids have?
kink by double bond
What can prokaryotes have?
Either 1 or 2 membranes
What does Low density lipoprotein carry?
Cholesterol
How is cholesterol released into a cell?
receptor mediated endocytosis
What is the enzyme called Na+/K+ ATPase?
hydrolyse ATP to actively transport Na out and K+ into cells
What is the enzyme called Ca 2+ATPase?
Ca2+ pump of sarcoplasmic reticulum in muscle cells
What does Ca2+ pump have?
spanning alpha helices and 3 domains
What do P-type ATPases do?
Transport lipid across membrane
What do flippases do?
Flip phospholipids and maintain membrane assymetry
What are ATP-binding cassette transporters?
membrane protein that can cause drug resistance
What do MDR proteins show?
4 DOMAINS
- 2 membrane binding
- 2 ATP binding cassettes
What are histidine permeases?
proteins that transport molecules into a cell
What are secondary transporters?
Anti porters
symporters
What are anti porters?
use electro-chem gradient of Na to pump Ca out of cell
What are Symporters?
Same direction, glucose into cells powered by Na entry too
