4a

Question 1

does atp conc need to be high or low in order to promote reactions

Answer 1

the atp conc needs to be high if u want to use it to promote reactions

Question 2

what do we use atp for

Answer 2

we use to to make unfavourable reactions favourable

Question 3

atp hydrolysis needs to occur where and why

Answer 3

atp hydrolysis needs to occur in enzymes bc theres a big kinetic energy barrier for its hydrolysis

Question 4

name all the common activated electron carriers in metabolism

Answer 4

NAD+ and NADH
FAD and FADH2

we also talk a little bit about NADP and NADPH

Question 5

whats the diff between NAD+ and NADP

Answer 5

NADP has an extra phosphate on the ribose

Question 6

describe NAD

Answer 6

pyridine with an amide as a substituent from the top right carbon

the N is said to be + bc its got no H

Question 7

describe NADH

Answer 7

u have the pyridine but the N is now neutral ,, u have 2 double bonds on the pyridine and u have 2 H’s at the top

u still have the amide on the top right carbon

Question 8

how do u go from NADH to NAD+

Answer 8

u use the lone pair on the N and u carry this up to the H’s,, one of the CH bonds then is used to attack a ketone to give u an alcohol

the H of the CH stays on the alcohol

Question 9

how do u go from NAD+ to NADH

Answer 9

the alcohol with the H as a substituent on the C uses its CH bons to target the top C of the pyridine

the double bonds then resonate back onto the N! to neutralise it.

Question 10

a wedged H is called

Answer 10

pro R

Question 11

a dashed H is called

Answer 11

pro S

Question 12

Pro S and Pro R are

Answer 12

enantiomers

Question 13

what is NADP+ used for

Answer 13

its used for anabolism!! // anabolic reactions

Question 14

what does the phosphate on NADP allow enzymes to do

Answer 14

it allows enzymes to distinguish between NADP+ and NAD+

bc the only diff between them is the phosphine on the ribose

Question 15

describe FAD

Answer 15

u have a benzene with 2 me coming from its LHS carbons

u then have a symmetric NN ring
then u have a cyclic ring with a keton,, NH ,, ketone then N.

in FAD,, only one of the Ns have a H on it.

theres also a double bond poiting down from the NN and ketone cyclic structure

Question 16

2 diff routes u can go from FAD to FADH2

Answer 16

hydride
radical mechanism

Question 17

describe the hydride mechanism to go from FAD to FADH2

Answer 17

H- attacks the N ,, the double bonds move and the last one attached a H+,, protonating the last N. so all the Ns now have a H attached to it.

Question 18

describe the radical mechanism for making FADH2 from FAD

Answer 18

1e- movement to the C between the NN and the ketone rings,, the double bond then attacks a BH H.

the radical then is combined with 1 e- from the other double bodn to form a double bond

and the other e- from the bouble bond puts a radical on the N,, which is then use to attack a H+ to give u all the N’s protonated

Question 19

when u have the radical mechanism,, what can be used as the 1e- movement

Answer 19

u can have a doubel bond give u one electron,, this can from from coenzyme A giving u one e- from its enolate form

Question 20

how many e- does NAD gve

Answer 20

1 e- 1H

Question 21

how many e- does FAD give

Answer 21

it gives 2e- and 2H+

Question 22

whats a thiol

Answer 22

molecule with S in it

Question 23

whats a thiol ester

Answer 23

carbonyl directly attached to an S

Question 24

is acetyl coenzyme a a thio ester

Answer 24

yes!!!

u have R,, ketone,, S and then CoA written

Question 25

what C is more electrophilic,, aka what C is more positive,, a thioester C or an ester C

Answer 25

a thioester is more electrophilic bc theres poor overlap between the 3p orbital of sulfer whereas in the ester,, theres good overlap between the 2p of the oxygens

Question 26

the lower the pka

Answer 26

the more acidic smt is

Question 27

ka =

Answer 27

[H3O+][A-] //// [HA]

Question 28

pka of acetone

Answer 28

18

Question 29

pka of ester

Answer 29

25

Question 30

pka of thioesyer

Answer 30

20

Question 31

can a thioester form an enol

Answer 31

yesssss its kinda easy bc its got a pka of 20 meaning the Hs are more acidic and more likely to fall off than the Hs in an ester

Question 32

thiolester + nucleophile

Answer 32

the C is attcked by the nuc the thiol bit is kicked off bc its acc a better leaving group than an O. so now u have a thiol and a diff ester// carbonyl compound

Question 33

is Sr- or OR- more stable

Answer 33

SR- is more stable than OR- which is why the thiol is a good lg

Question 34

is a thiol more acidic than an alcohol

Answer 34

yesss a thiol is more acidic than an alcohol pka is around 10-11 for thiol pka is around 15 for OH

Question 35

why else is the LG thiol more favoured

Answer 35

bc its larger,, meaning less H bonding is needed for solvation so entropy is larger

Question 36

in a thioester,, can u swap the thiol for a diff group

Answer 36

yes!! u just need to attach the carbonyl C with the thing u want to replace it with

Question 37

whats it called when u add smt else to the thiol,, and that smt else has a carbonyl group on it

Answer 37

carbonyl group = acyl group so its called an acylation reaction

Question 38

can thioesters turn into enols

Answer 38

yesss they readily form,, u just need to remove the alpha H's