AA, proteins and DNA Flashcards Preview

Organic Chemistry Year 2 > AA, proteins and DNA > Flashcards

Flashcards in AA, proteins and DNA Deck (35)
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1

functional groups of AA

NH2 and COOH

2

how many naturally occurring AA are there in the body

20

3

what type of AA are found in the body

alpha
the NH2 is always on the carbon next to COOH

4

generic formula for an alpha AA

R
I
H2N - C - COOH
I
H

5

which enantiomer do alpha AA exist as in nature

- enantiomer

6

is the product from AA being synthesises naturally optically active

no
a racemix is formed as the CN- can attack from above or below the planar C=O

7

in what form do AA exist as solids

zwitterions

8

what colour are zwitterions

white solids

9

zwitterion

ions which have both a permanent positive and negative charge but are neutral overall

10

zwitterion AA

R
I
H3N+ - C - COO-
I
H

11

what happens to AA in acidic conditions

gains a proton on NH2 group

12

what happens to AA in alkaline conditions

loses a proton from COOH group

13

peptide linkage

CONH

14

what name is given to chains of AA up to 50 AA

polypeptide

15

what name is given to a chain of AA with more than 50

proteins

16

conditions needed for hydrolysis to occur

6 mol dm3
HCl
reflux for 24 hours

17

primary structure

sequence of AA along the protein chain bonded by covalent bonds

18

secondary structure

shape of the protein chain

19

how is the secondary structure held together

hydrogen bonding

20

tertiary shape of a protein

alpha helix or beta pleated sheet is folded into a complex 3D shape

21

how is the tertiary structure held together

hydrogen bonding
ionic interactions
disulphide bridges
van der waals

22

what is TLC plate made of

plastic sheet coated with silica
this is the stationary phase

23

describe the process of TLC

spot the samples onto a pencil line a few cm above the base
place this in a beaker with solvent lower than the pencil line
wait until the solvent front is almost at the top of the plate
remove and analyse

24

how do you calculate the Rf value

distance moved by that substance divided by the distance moved by the solvent front

25

what is 2D TLC

uses a square TLC plate
spot the AA in one corner then run TLC in first solvent
flip the plate through 90' and repeat TLC in a second different solvent

26

what is an enzyme

protein based catalyst that speed up reactions in the body by factors of up to 10^10

27

structure of an enzyme

globular protein with a creft/crevice in it, known as an active site

28

how structure help the function

the reacting molecules fit precisely into the active site and are held at exactly the right orientation to react

29

enzymes increase the ror

reacting molecules form temporary bonds to the enzyme
this weakens the bonds in the molecules promotes electron movement and lowers Ea

30

what does the stereospecificity of enzymes mean

active sites are so selective of the shape of substrates that only reactions involving one enantiomer are catalysed