1.3 membrane structure

Question 1

integral proteins

Answer 1

are amphipathic and are embedded in the plasma membrane. Mostly they pass completely through the membrane.

Question 2

peripheral proteins

Answer 2

polar (hydrophilic) and are attached to the outside of the plasma membrane.

Question 3

channels

Answer 3

some proteins have a pore/channel that allows passive transport (no energy required) of substance between the inside and outside of the cell
-integral proteins which contain a pore via which ions may cross from one side of the membrane to the other
-only select for specific ions
-much faster rate of transport than carrier proteins
-only move molecules along a concentration gradient (i.e. are not used in active transport)

Question 4

carriers

Answer 4

these proteins bind to the substances on one side of the membrane and then change shape to transport them to the other side. carrier proteins that use energy to change shape are termed PROTEIN PUMPS
-Integral proteins bind a solute and undergo a conformational change to move the solute across the membrane
-only bind a specific molecule via a recognition site
-slower rate of transport than channel proteins
-May also move molecules against concentration gradients in the using ATP (active transport)

Question 4

recognition

Answer 4

certain proteins help the cell in differentiating between self and non self cells (imp in triggering an immune response)
-may function as markers for cellular identification

Question 5

receptors

Answer 5

these proteins usually span the whole membrane to relay info from the insdie or outside of the cell

Question 6

enzymes

Answer 6

these are proteins that enhance the rate of reactions that happen at the membrane level

Question 7

glycolipids

Answer 7

phospholipid attached to carbohydrate. important in maintaining structure and differentiating betwen self and non-self cells

Question 8

functional difference between glycolipids and glycoproteins

Answer 8

glycolipids facilitate cellular recognition while glycoproteins serve as receptors for chemical signals.