amino acids

Question 1

draw general structure of amino acid

Question 2

what does amine group do

Answer 2

uses lone pair to accept a proton

Question 3

what does COOH group do

Answer 3

-donates proton
-undergoes condensation reactions (esterification)

Question 4

all amino acids have chiral centre and so are optically active. which amino acid doesn’t have chiral centre?

Answer 4

glycine

Question 5

what do amino acids exist as?

Answer 5

zwitterions (could be called solid structure/stable species in neutral solution)

Question 6

define zwitterion

Answer 6

molecular ion with positive and negative charges and is neutral overall

Question 7

what would have higher solubility in a polar solvent

Answer 7

more charged

Question 8

structure of zwitterions?

Answer 8

giant ionic lattice

Question 9

what are proteins?

Answer 9

polymers of amino acids joined by amide bonds formed in condensation reactions

Question 10

reagent for hydrolysis of protein

Answer 10

NaOH/HCl

Question 11

during hydrolysis of protein, with strong base what is formed

Answer 11

sodium carboxylate

Question 12

during hydrolysis of protein, with strong acid what is formed

Answer 12

ammonium salt

Question 13

describe primary structure of protein

Answer 13

-sequence of amino acid
-amide bonds between amino acids

Question 14

describe secondary structure of protein

Answer 14

-alpha-helix and beta-pleated sheet
-hydrogen bonds due to electronegative O and N
-O-H and N-H bonds highly polar
-attraction between lone pair on δ- O and δ+ H

Question 15

describe tertiary structure of a protein

Answer 15

-3D shape
-formed from hydrogen bonds, ionic bonds and disulfide bridges between R groups

Question 16

describe features of enzyme

Answer 16

-catalysts of biological reactions
-have a stereospecific active site; only one of the pair on enantiomers can fit into active site

Question 17

describe DNA

Answer 17

-made up of nucleotide monomers
-consists of 2 strands of DNA joined by H bonds between complementary base pairs to form double helix

Question 18

what does each nucleotide contain

Answer 18

-phosphate ion
-2-deoxyribose
-base

Question 19

how many hydrogen bonds between A and T

Answer 19

2

Question 20

how many hydrogen bonds between C and G

Answer 20

3

Question 21

what does complementary mean

Answer 21

A only forms hydrogen bonds with T
C only forms hydrogen bonds with G

Question 22

use of cisplatin

Answer 22

kills cancer cells

Question 23

describe how cisplatin works

Answer 23

-binds to guanine; forms coordinate bonds with N atoms not bonded to 2-deoxyribose or to cytosine
-stops DNA replication
-Cl⁻ ligands replaced by guanine in ligand substitution

Question 24

side effects of cisplatin

Answer 24

-hair loss
-fertility issues
-weakened immune system