Membranes

Question 1

Whay is the phospholipid membrane described as a fluid mosaic?

Answer 1

mosaic because of the many proteins imbedded within and fluid because of how those proteins can move around within the membrane.

Question 2

What molecule within the cell membrane helps with temperature control?

Answer 2

Cholesterol by interfering with close packing of fatty acid tails and hindering phosolipid movement

Question 3

Intergral protein

Answer 3

penetrate the interior of the membrane, consisting of hydrophobic amino acid stretches

Question 4

Peripheral membrane protein

Answer 4

not embedded in the membrane just loosely bound to the surface of the cell

Question 5

what are the 6 primary functions of a membrane protein

Answer 5

1) providing stronger membrane framework
2) to aide with cell to cell recognition
3) to form tight membrane junctions
4) work as enzymes
5) work as receptors
6) work as transportors (carrier and channel proteins)

Question 6

Membrane carbohydrates do what?

Answer 6

they help with cellular recognition, allows removal of foreign cells. could be either a glycolipid or a glycoprotein

Question 7

diffusion rate varies according to…

Answer 7

size, shape and charge of molecules

Question 8

What is the difference between a carrier and a channel protein?

Answer 8

Channel proteins simply provide a channel through the membrane, carrier proteins physically grab and export the proteins through the membrane.

Question 9

osmoregulation

Answer 9

regulation of water gain/loss within the cell

Question 10

tugor pressure

Answer 10

the pressure applied by the plant cell wall when the cell begins to swell

Question 11

Aquaporins

Answer 11

channels in the membrane that allow water to cross the membrane (allows water to pass at a reasonable rate since it is polar)

Question 12

explain the process of active transport.

Answer 12

solute binds to specific site on the transport protein, an ATP molecule transfers one of it’s phosphate group causing the protein to change it’s shape, the phosophate group now detaches and the protein is ready to be used again.

Question 13

Co-transporters

Answer 13

couple the movement of materials against their concentration gradient (energy requiring) with materials moving with their concentration gradient (energy yeilding)

Question 14

Exocytosis

Answer 14

a transport vesicle budding from the golgi removes large molecules from the cell by fusing with the plasma membrane

Question 15

Endocytosis

Answer 15

Process of the cell taking in extracellular content there are 3 types
1) phagocytosis (cellular eating)
2) phinocytosis (cellular drinking)
3) receptor mediated (highly specific, receptor proteins for a certain molecule are embedded within the plasma membrane)