Amino acids, Proteins and DNA

Question 1

What 2 groups does an amino acid contain

Answer 1

Carboxyl group
Amino group

Question 2

Which part of an amino acid reacts with a base

Answer 2

Carboxyl group

Question 3

Which part of an amino acid reacts with an acid

Answer 3

Amino group

Question 4

Write an equation for the reaction between 2-aminopropanoic acid and H+

Answer 4

Question 5

Write an equation for the reaction between 2-aminobutanoic acid and NaOH, name the organic product formed

Answer 5

Question 6

What is the name of the point at which amino acids are neutral

Answer 6

Isoelectric point

Question 8

What determines how acidic or basic an amino acid is

Answer 8

The R group attached,
Alkyl groups are electron releasing
Acyl groups are electron withdrawing

Question 9

How do amino acids exist in neutral solution

Answer 9

As zwitterions

Question 10

How do amino acids exist in a solution of low pH

Answer 10

NH2 gains H+ to become NH3+

Question 11

How do amino acids exist in a solution of high pH

Answer 11

COOH looses H+ to become COO-

Question 12

Describe the structure and melting point of amino acids in the solid form

Answer 12

They have crystalline structures with high melting points due to the strong electrostatic forces of attraction than must be overcome between the zwitterions

Question 13

What occurs when an amino acid reacts with an alcohol in the presence of conc H2SO4

Answer 13

• The carboxyl group undergoes esterification
• NH2 gains a proton from the sulfuric acid

Question 14

Write an equation for the reaction between 2-aminopropanoic acid and methanol in the presence of H2SO4

Question 15

Which part of an amino acid reacts with an acyl chloride

Answer 15

Amino group

Question 16

Which part of an amino acid reacts with an acid anhydride

Answer 16

Amino group

Question 17

What is the major product when we react an amino acid with excess halogenoalkane

Answer 17

Quaternary ammonium salt