amino acids, protein ,DNA

Question 1

what is amphoteric?

Answer 1

displays both acidic and base properties

Question 2

what is the only amino acid that is not optically active

Answer 2

H
HOOC-C-NH3
H
where the r group is H glycine

Question 3

how do you name proteins?

Answer 3

x-amino xanoic acid

Question 4

what is a zwitter ion and where do they exist?

Answer 4

a molecule with both positive and negatvie ion

they exist on the amino acid isoelectric point

Question 5

what is the isoelectric point?

Answer 5

the isoelectric point is the pH where the average charge is 0.It is dependent on the R group

Question 6

draw a zwitter ion?

Answer 6

H
-OOC - C-N +H
H

Question 7

how does ph affect zwitter ion?

Answer 7

if the pH is lower than the isoelectric point it means H+ is donated to amino acid
(O-C=O ) -> -HOC=O
if the pH is higher than than isoelectric point it means that that the amino acid donates the H+ NH3+ -> NH2

Question 8

what can be used to identify and seperate amino acids?

Answer 8

thin layer chromotography

Question 9

describe the steps of TLC

Answer 9

draw base line with pencil
silica for stationary point
place plate in solvent (baseline slightly above solvent) cover with glass lid
leave until solvent had moved to near top of plate
take off and mark solvent front

Question 10

as amino acids are colourless what are the 3 methods used to see the TLC

Answer 10

spray with flurosecent dye then shine with UV light. colourless spots shown and can be drawn around
place the chromatogram in a sealed jaw with few iodine crytals the iodine vapour sticks to the plate turning it purple
ninhydrine also acts a locating agent and can be sprayed on

Question 11

what are 3 things that affect Rf vaules?

Answer 11

temperature
solvent
material of stationary point

Question 12

what are the conditions for hydrolsis of protein into amino acids?

Answer 12

6mol/dm3
110 degrees
reflux for 24 hours

Question 13

why is an enzyme not guarenteed to work ?

Answer 13

most amino acids are optically active this means that an enzyme has to be stereospecific to fit the substrate and catalyse the reaction

Question 14

how does antibiotics worK?

Answer 14

it is an inhibitor that binds with the active site of the enzyme responsible in making cell wall for bacteria

Question 15

how is the phosphate sugar backbone formed?

Answer 15

condensational polymerisation between phosphate and sugar removing water
phosphodiester bonds are formed and water is elminated

Question 16

how do nucleotides hydrogen bond?

Answer 16

hydrogen bonds only form between a delta positive H and an electronegative element with a lone pair e.g O,N only at the correct distance

Question 17

how many hydrogen bonds do A,T and C,G form?

Answer 17

A,T - 2

C,G -3

Question 18

why can no other base pair?

Answer 18

the partially charged atoms would be too close and repel each other or not get close enough for a hydrogen bond to form

Question 19

what is cis plantain?

Answer 19

anti cancer drug
square planar complex
platinum metal ion
2 ammonia ligands
and 2 chloride ion ligands

Question 20

what does cis- plantin do?

Answer 20

binds to DNA in cancer cells

as it binds it stops cell division killing it

Question 21

how does cis plantin stop cell division?

Answer 21

Cl- are easily displaced due to the weak coordinate bond and detatch from the complex
the platinum can then bond to the nitrogen on guanine
the second cl- ion can do the same bonding to another guanine
this causes distortion in the DNA strand so it cannot unwind and therefore cant copy

Question 22

what is the negative of cis plantin and solution

Answer 22

it can also attack healthy cells stopping them from reproducing
e.g blood cells affecting immune system and increase the risk of infection and kidney damage
this can be reduced by using lower doses and more targeted