Membranes II transport- Lecture 8/20/21

Question 1

Relative Na+ concentration

Answer 1

Much higher out of the cell

Question 2

Relative K+ concentration

Answer 2

Much higher inside cell

Question 3

Relatice Mg2+ conc

Answer 3

Higher outside the cell

Question 4

Relative Ca 2+ conc

Answer 4

Higher outside cell

Question 5

Relative Cl- conc

Answer 5

Higher outside the cell

Question 6

Channel proteins

Answer 6

Allow passive transport of one molecule down conc gradient

Question 7

Carrier protein

Answer 7

Allows one molecule at a time down conc gradient, passive

Question 8

Active transport

Answer 8

Pumps a molecule up its conc gradient using energy

Question 9

Coupled transport

Answer 9

Couples the energy harvested from molecules down their gradient to pump others up

Question 10

Symporter

Answer 10

Pumps two molecules in same direction

Question 11

Antiporter

Answer 11

Pumps them in opposite directions

Question 12

ABC superfamily

Answer 12

ATP binding cassette superfamily

Question 13

Diseases involving mutations of ABC

Answer 13

Cystic fibrosis -> mutation of CF transmembrane regulator
Hypoglycemia in infancy -> Sulfanylurea receptor
Drug resistance -> overexpresion of p=glycoproteins/MDR complex pumps out chemo from cells allowing survival of cancer cells

Question 14

Tangier’s disease

Answer 14

Rare disease leading to severe HDL. Deficiency in the plasma. Accumaulation of cholesteryl ester in various tissues, leading to lymphadenopathy, hepatosplenomegaly, and severe CAD

Question 15

Mutation in Tangier’s disease

Answer 15

ABC-1 is mutated, preventing the efflux of cholesterol from the cell, leads to build up in tissues

Question 16

Pinocytosis

Answer 16

Cell “drinking” essential for life but not this class

Question 17

Receptor-mediated endocytosis

Answer 17

Used for anything smaller than a virus, leads to invagination of the cell membrane with Catherine coated vesicles

Question 18

Phagocytosis

Answer 18

Anything bacterium and larger, leads to evagination of the membrane to engulf the target using actin mediated ways

Question 19

Phagosome

Answer 19

Rapidly acidified by ATPase hydroium pumps

Question 20

Clathrin coated pits

Answer 20

In RME, lipid rafts concentrate ligand receptor complexes and clathrin initiates the invagination, quickly falls off

Question 21

Ligand degradation

Answer 21

Low pH in the endosome leads to dissacocition, early endosome fuses with lysosome and receptors return to cell surface

Question 22

Viral infection

Answer 22

Rabies and flu escape the low pH by fusing with endosome dumping their contents into the cell

Question 23

Familial hypercholesterolemia

Answer 23

Defect in LDL uptake, can’t concentrate the complexes for uptake