Membrane function Flashcards
What is the function of the plasma membrane?
Barrier, transport, signal transduction
What is the function of inner membrane of mitochondria?
Energy transduction
What is the function of the outer membrane of the mitochondria?
Barrier
What is the function of the rough endoplasmic reticulum?
Translation protein processing
What is the function of the smooth endoplasmic reticulum?
Synthesis of complex lipids,
What is the structure of the golgi?
Post-translational modification
Processing for secretion
What is the function of nuclear membranes?
Attachment of chromatin,
What is the function of lysosomes?
Hydrolytic enzymes
What is the function of peroxisomes?
Fatty acid oxidation
What is movement of molecules across membrane dependant on and what is this called?
- Movement of these
molecules is dependent
on their concentration - This is called simple
diffusion
What is a uniporter protein?
A uniporter is a membrane transport protein that transports a single species of substrate (charged or uncharged) across a cell membrane. It may use either facilitated diffusion and transport along a diffusion gradient or transport against one with an active transport process.
What is a symporter protein?
Symporters are proteins that simultaneously transport two molecules across a membrane in the same direction.
What is an antiporter?
An antiporter is a membrane protein that transports two molecules at the same time in the opposite direction.
Where are GLUT1 transporters located and what is there function?
-Located in all mammalian tissues
-Involved in basal glucose uptake
Where are GLUT2 transporters located and what is there function?
-Located in the liver and pancreatic beta cells
-Involved in the pancreas, plays a role in regulation of insulin
Where are GLUT3 transporters located and what is there function?
-Located in all mammalian tissues
-Involved in basal glucose uptake
Where are GLUT4 transporters located and what is their function?
-Located in muscle and fat cells
-These amount in muscle plasma membrane and increases with endurance training
Where are GLUT5 transporters located and what is their function?
-Located in small intestine
-Involved primarily a fructose transporter
How can transport of glucose be increased?
- Transport of glucose can be increased by
increasing the number of transporters on
the cell surface - GLUT4 transporters are increased on
muscle and adipocytes by insulin
What is active transport?
-Transports against the electrochemical gradient and requires energy in the form of ATP
What is foxglove?
-Used to make digoxin
-Cardiotonic steroid
-Inhibits the Na+/K+ pump
-This increases Ca2+ and hence increases strength of contraction
Steps involved in SGLUT-1 and 2
- Na+/K+ pump will release Na+ into lumen, increasing concentration outside of cell
- This will allow the Na+ glucose symporter to transport both Na+ and glucose together back into the cytosol.
What is cellular asymmetry maintained by
Asymmetry is maintained by tight junctions
What is in rehydration therapy and what does it target?
-8 teaspoons of sugar
-1 teaspoon of salt
-1 litre of water
What are gated channels?
Transmembrane proteins that form pores for
the movement of ions
What are gated channels?
Transmembrane proteins that form pores for
the movement of ions
What are gated channels activated/opened by?
- Activated/opened by different stimuli including
– voltage
– ligand
– phosphorylation
What is cystic fibrosis caused by and what does this result in?
-Single deletion at position 508
-individuals that carry the deletion in both copies of the gene produce a
protein that fails to insert into the membrane
What is compartmentalization?
When Intracellular membranes create local environments and separate
reactions
What is compartmentalization required for?
Compartmentalization is required for
energy production
What does mannose 6-phosphate do?
Mannose 6-phosphate targets enzymes
made in the golgi to the lysosome
What is I cell disease and what does it cause?
What is it due to?
-I cell disease is autosomal recessive
-causes skeletal abnormalities and mental retardation
-Due to a mutation causing mannose-6-phosphate to not be phosphorylated
What is unique feature to signal for apoptosis?
The exposure of phosphatidylserine (PS) on the outer plasma membrane has long been considered a unique feature of apoptotic cells.
‘eat me signal’
What are membrane glycoproteins involved in?
Membrane glycoproteins are involved in cell to cell recognition
