Membrane function

Question 1

What is the function of the plasma membrane?

Answer 1

Barrier, transport, signal transduction

Question 2

What is the function of inner membrane of mitochondria?

Answer 2

Energy transduction

Question 3

What is the function of the outer membrane of the mitochondria?

Answer 3

Barrier

Question 4

What is the function of the rough endoplasmic reticulum?

Answer 4

Translation protein processing

Question 5

What is the function of the smooth endoplasmic reticulum?

Answer 5

Synthesis of complex lipids,

Question 6

What is the structure of the golgi?

Answer 6

Post-translational modification
Processing for secretion

Question 7

What is the function of nuclear membranes?

Answer 7

Attachment of chromatin,

Question 8

What is the function of lysosomes?

Answer 8

Hydrolytic enzymes

Question 9

What is the function of peroxisomes?

Answer 9

Fatty acid oxidation

Question 10

What is movement of molecules across membrane dependant on and what is this called?

Answer 10

• Movement of these
  molecules is dependent
  on their concentration
• This is called simple
  diffusion

Question 11

What is a uniporter protein?

Answer 11

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.

Question 12

What is a symporter protein?

Answer 12

Symporters are proteins that simultaneously transport two molecules across a membrane in the same direction.

Question 13

What is an antiporter?

Answer 13

An antiporter is a membrane protein that transports two molecules at the same time in the opposite direction.

Question 14

Where are GLUT1 transporters located and what is there function?

Answer 14

-Located in all mammalian tissues
-Involved in basal glucose uptake

Question 15

Where are GLUT2 transporters located and what is there function?

Answer 15

-Located in the liver and pancreatic beta cells
-Involved in the pancreas, plays a role in regulation of insulin

Question 16

Where are GLUT3 transporters located and what is there function?

Answer 16

-Located in all mammalian tissues
-Involved in basal glucose uptake

Question 17

Where are GLUT4 transporters located and what is their function?

Answer 17

-Located in muscle and fat cells
-These amount in muscle plasma membrane and increases with endurance training

Question 18

Where are GLUT5 transporters located and what is their function?

Answer 18

-Located in small intestine
-Involved primarily a fructose transporter

Question 19

How can transport of glucose be increased?

Answer 19

• 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

Question 20

What is active transport?

Answer 20

-Transports against the electrochemical gradient and requires energy in the form of ATP

Question 21

What is foxglove?

Answer 21

-Used to make digoxin
-Cardiotonic steroid
-Inhibits the Na+/K+ pump
-This increases Ca2+ and hence increases strength of contraction

Question 22

Steps involved in SGLUT-1 and 2

Answer 22

1. Na+/K+ pump will release Na+ into lumen, increasing concentration outside of cell
2. This will allow the Na+ glucose symporter to transport both Na+ and glucose together back into the cytosol.

Question 23

What is cellular asymmetry maintained by

Answer 23

Asymmetry is maintained by tight junctions

Question 24

What is in rehydration therapy and what does it target?

Answer 24

-8 teaspoons of sugar
-1 teaspoon of salt
-1 litre of water

Question 25

What are gated channels?

Answer 25

Transmembrane proteins that form pores for
the movement of ions

Question 25

What are gated channels?

Answer 25

Transmembrane proteins that form pores for
the movement of ions

Question 26

What are gated channels activated/opened by?

Answer 26

• Activated/opened by different stimuli including
  – voltage
  – ligand
  – phosphorylation

Question 27

What is cystic fibrosis caused by and what does this result in?

Answer 27

-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

Question 28

What is compartmentalization?

Answer 28

When Intracellular membranes create local environments and separate
reactions

Question 29

What is compartmentalization required for?

Answer 29

Compartmentalization is required for
energy production

Question 30

What does mannose 6-phosphate do?

Answer 30

Mannose 6-phosphate targets enzymes
made in the golgi to the lysosome

Question 31

What is I cell disease and what does it cause?
What is it due to?

Answer 31

-I cell disease is autosomal recessive
-causes skeletal abnormalities and mental retardation
-Due to a mutation causing mannose-6-phosphate to not be phosphorylated

Question 32

What is unique feature to signal for apoptosis?

Answer 32

The exposure of phosphatidylserine (PS) on the outer plasma membrane has long been considered a unique feature of apoptotic cells.
‘eat me signal’

Question 33

What are membrane glycoproteins involved in?

Answer 33

Membrane glycoproteins are involved in cell to cell recognition