Polymers and Life - Amines and Amino Acids

Question 1

what is the structure of a primary amine?

Answer 1

Question 2

what is the structure of a secondary amine?

Answer 2

Question 3

what is the structure of a tertiary amine?

Answer 3

Question 7

what is the functional group for amines?

Answer 7

at least one C-N bond, other bonds on the N are either to a H or other alkyl groups

Question 8

what is the solubility of amines in water?

Answer 8

small amines are soluble in water, large amines are not

Question 9

why are small amines soluble in water and large amines insoluble?

Answer 9

there is a lone pair on an electronegative atom with 2H also attached to it

the lone pair and H atoms can hydrogen bond with water

in small amines, the bonds are sufficient to solvate the molecule

in large amines, molecules would have to break many H bonds already present while only forming 3 H bonds so cannot solvate

Question 10

what is the functional group of amides?

Answer 10

Question 11

how are primary amines named?

Answer 11

either amino as a prefix - used with <1 group

or amine as a suffix - used with 1 group

Question 12

are amines acidic or basic?

Answer 12

basic

Question 13

how are amides formed?

Answer 13

when an amine and carboxylic acid react

Question 14

why don’t amines and amides act similarly?

Answer 14

because the carbonyl group on an amide makes it act more like an ester than an amine

Question 15

what is the structure of a primary amide?

Answer 15

Question 16

what is the structure of a secondary amide?

Answer 16

Question 17

what is the structure of a tertiary amide?

Answer 17

Question 21

what are primary amides made from?

Answer 21

ammonia + acyl chloride

Question 22

why are primary amides made from acyl chlorides and not carboxylic acids?

Answer 22

carboxylic acids do not react easily with ammonia but acyl chlorides do, and they produce the same product

Question 23

what are secondary amides derived from?

Answer 23

primary amine + carboxylic acid

Question 24

what type of reaction produces amides?

Answer 24

condensation reaction

Question 25

what is the by-product of the reaction to produce amides?

Answer 25

hydrogen chloride

Question 26

what is the equation for the hydrolysis of primary amides in acidic conditions?

Answer 26

RCONH₂ -> RCOOH + NH₄

Question 27

what is the equation for the hydrolysis of primary amides in alkaline conditions?

Answer 27

RCONH₂ -> RCOO^- + NH₃

Question 28

what is the equation for the hydrolysis of secondary amides in acidic conditions?

Answer 28

RCONHR^| -> RCOOH + R^|NH₃⁺

Question 29

what is the equation for the hydrolysis of secondary amides in alkaline conditions?

Answer 29

RCONHR^| -> RCOO^- + R^|NH₂

Question 30

what is a conjugate base?

Answer 30

an acid that has donated a H+

Question 31

why are conjugate bases basic?

Answer 31

as the acids have donated a H+, they can now re-accept them, making them basic

Question 32

what strength of conjugate bases do strong acids form and why?

Answer 32

weak conjugated bases strong acids fully dissociate so are less likely to re-accept the proton

Question 33

what is the more common name for aminocarboxylic acids?

Answer 33

amino acids

Question 34

what is an alpha amino acid?

Answer 34

an amino acid with a central carbon atom, which is attached to the amine and carboxyl groups

Question 35

what is an alpha carbon in amino acids?

Answer 35

the central carbon - the one attached to the -COOH and amine groups

Question 36

what is a zwitterion?

Answer 36

a molecule with two functional groups, where one it positive and one is negative

Question 37

what is the overall charge of a zwitterion?

Answer 37

neutral

Question 38

which amino acid isn't chiral and why?

Answer 38

glycine, the R group is a H so the alpha carbon is bonded to 2 H groups

Question 39

what is the overall charge of amino acids?

Answer 39

neutral

Question 40

how do amino acids act in basic conditions?

Answer 40

as an acid

Question 41

how do amino acids act in acidic conditions?

Answer 41

as a base

Question 42

how do amino acids form zwitterions?

Answer 42

as they receive or donate protons in aqueous conditions

Question 43

what part of an amino acid accepts protons?

Answer 43

the NH₂ group

Question 44

what part of an amino acid donates protons?

Answer 44

the COOH group

Question 45

draw an amino acid in zwitterion form

Answer 45

Question 47

what type of intermolecular bonds do amino acid zwitterions form in aqueous conditions?

Answer 47

permanent dipole - permanent dipole

Question 48

draw an amino acid in neutral, acidic and basic conditions

Answer 48

Question 50

how do amino acids act as buffers?

Answer 50

the zwitterions buffer the solution by forming an acidic or basic ion, depending on the pH, to form an equilibrium

Question 51

where are peptide bonds formed on amino acids?

Answer 51

between the -NH₂ and -COOH

Question 52

draw a peptide link between two amino acids

Answer 52

Question 53

what type of reaction forms peptide bonds?

Answer 53

condensation reactions

Question 55

how are dipeptides names?

Answer 55

the first 3 letters of each amino acid in order of bonding

Question 56

what does chiral mean?

Answer 56

non-superimposable

Question 57

what is a chiral centre?

Answer 57

a molecule bonded to 4 different groups

Question 58

what are enantiomers?

Answer 58

a pair of molecules that are mirror images of each other

Question 59

what is an essential amino acid?

Answer 59

an amino acid that can only be obtained through diet

Question 60

what is a non-essential amino acid?

Answer 60

an amino acid that can be synthesised by the body