Lipids II Flashcards
- What are functions of a plasma membrane?
protection, cell adhesion, signaling, transport
PAST
- What features does a plasma membrane have with regard to permeability and why is that the case?
impermeable towards hydrophilic molecules because it require a transport ions across membrane
- What are the three major transport types and do they require energy?
passive
active
bulk
*passive transport doesn’t require energy
- What is uniport, symport and antiport (with regard to energy required and molecules moved)?
energy source: ATP
uniport: transport of one molecule into the cell
Energy source: electrochemical gradient
symport: transport of two molecules in the same direction (into cell)
antiport: transport of two molecules in opposite direction
- What are two types of bulk transport and is energy required? What “vessel” is required?
endocytosis: into cytoplasm
exocytosis: out of cytoplasm
*vesicular transport is required to move large molecules OR large amounts of small molecules
- What is an example for an uniporter found in rods, transporting what?
glucose unitporter, GLUT-1
- What is an example for an antiporter found in rods, transporting what?
Na/Ca exchanger (NCx) secondary active transport
- Which for 4 types of multiprotein complexes are found in a membranes involved in transport, signaling, adhesion and protection?
Gap junctions
tight junctions
desmosomes
adherens junctions
Which one is the membrane model that is still accepted today and what are the major features of that model?
fluid mosaic model
- fluidity
- dynamic
-molecules floating
Which lipid classes are the main types found in plasma membranes?
glycerides (contains glycerol)
non-glycerides (sphingolipids, steroid + cholesterol)
Which lipid types are the most abundant?
- Glycerophospholipids/ phosphoglycerides
- Sphingolipids (rafts)
- Cholesterol (rafts)
Which 3 types of membrane proteins exist (with regard to location and attachment features)?
intergral membrane proteins
peripheral membrane proteins
lipid-anchored proteins
What are the major (important) features of these three membrane proteins types (implied by their name)?
integral - permanently bound
peripheral - temporarily bound
lipid-anchor - permanently placed with anchor
Which protein structure of transmembrane (TM) -proteins is the predominant form in our membranes – a helix or b-barrel?
alpha helical is dominant
What would be an example for a TM protein that is required for enzymatic activity (type/kind not a specific molecule)?
ATP synthase
- What would be an example for a TM-protein that is required for cell recognition (type/kind not a specific
molecule)?
T cell receptors , antibodies
- What would be an example for a TM-protein that is required for signal transduction / signaling (type/kind not a
specific molecule)?
Rhodopsin
- Where in the rod photoreceptor (structure/formation) is rhodopsin predominantly found (enriched) and where in this structure is it located?
Disc Membrane
RPE
- Of which two components is rhodopsin made of (type of molecule and specific name)?
opsin molecule and chromophore (11-cis-retinal)
- What happens to these two components when light hits rhodopsin?
conformational change > all-trans retinal = activated rhodopsin
- What is the name of the G-protein that interacts with activated Rhodopsin?
transducin
- What is the name of the ligand that keeps a special channel open to allow sodium to enter the rod? Bonus: What is the name of that channel?
clyclic GMP , Na+ channels must remain open
- What is the name of the enzyme generating GMP and what is it’s substrate?
phosopdiesterase (PDE)
- In the dark, the rod sodium channels are … resulting in….. resulting in .. resulting in …. ?
low cGMP > Na+ channel blocked > less (+) charge inside cell > hyperpolarization IPSPs
