lecture 19 electrophoresis

Question 1

define electrophoresis

Answer 1

movement of charged molecules in an external electric field

Question 2

define anode

Answer 2

+ive electrode that attacts anions

Question 3

define cathode

Answer 3

-ive electrode that attract cations

Question 4

define electromotive force

Answer 4

drives analyte ion to electrode of oppose charge. needs to be higher than EOF

Question 5

define electo endosmotic force (EOF)

Answer 5

bulk movement of water in opposite direction of anaylte ion

Question 6

define isoelectric point

Answer 6

pH where net charge is zero

Question 7

3 purposed of buffer

Answer 7

• provides ions for current
• set pH of system so molecules appropriately charged
• prevent pH change due to electrolysis of water

Question 8

direction cations and anions migrate

Answer 8

cations to cathode (-ive electrode)

Question 9

rlnshp between velocity (migration rate and voltage

Answer 9

higher the voltage faster the velocity

Question 10

rlnshp between velocity (migration rate and IS

Answer 10

increased IS results in increase current faster

Question 11

rlnshp between velocity (migration rate and molecular size

Answer 11

faster when size and is smaller, and spherical

Question 12

rlnshp between velocity (migration rate and net charge

Answer 12

affected by ph. faster when more -ve charges moves closer to anode (+ive electrode

Question 13

rlnshp between velocity (migration rate and [gel]

Answer 13

slower when [gel] is higher

Question 14

direction of DNA travel

Answer 14

DNA either uncharged or -ive charge. move to anode (+ electrode)

Question 15

why DNA has constant charge to mass ratio at pH 8

Answer 15

increase in -ive charged environement.move to anode (+ electrode)

Question 16

why serum protein electrophoresis performed at pH 8.6

Answer 16

so proteins will have net -ive charge and migrate to anode (+ive electrode)