Year 12 Chemistry Chapter 15

A patient’s blood tests indicate clinically low levels of vitamins C and D.

Which one of the following recommendations would most effectively and safely increase the patient’s levels of both vitamins C and D?

• Take a supplement of oil containing vitamin D regularly and eat citrus fruit daily.

• Eat more dairy products and spend one hour per day in the sun wearing sun protection.

• Dissolve a vitamin C tablet and a vitamin D tablet in a glass of water each morning and drink it.

• Eat more green leafy vegetables and spend one hour per day in the sun without wearing sun protection.

Aspartame is a widely used sweetener.

Aspartame

• contains a glycosidic link.

• is a naturally occurring sugar.

• has an energy content similar to that of sucrose.

• contains two amino groups in its chemical structure.

At the molecular level, Protein P is shaped like a coil. When a solution of Protein P is mixed with citric acid, solid lumps form.

The change in the structure of Protein P is due to

• hydrolysis.

• denaturation.

• polymerisation.

• the formation of peptide bonds.

Vitamins are required by the human body.

Which one of the following statements about vitamins is correct?

• Vitamin D₂ and vitamin D₃ are structural isomers.

• Vitamin D can be stored in the fatty tissues of the body.

• Vitamin D is water-soluble due to the presence of the hydroxyl group.

• Vitamin D is essential in the human diet as it cannot be manufactured by the body

Which one of the following fatty acids is an omega-3 fatty acid?

• arachidonic

• palmitoleic

• linolenic

• linoleic

Which one of the dipeptides shown to the left is made from α-amino acids?

• Structure A

• Structure B

• Structure C

• Structure D

The diagram shown to the left represents the structure of a non-essential vitamin.

• fat-soluble and can be produced by the human body.

• water-soluble and can be produced by the human body.

• fat-soluble and cannot be produced by the human body.

• water-soluble and cannot be produced by the human body.

The number of carbon-to-carbon double bonds (C=C) in a molecule can be identified by reacting the molecule with hydrogen gas, H₂. The type of reaction involved is an addition reaction.

10.0 g of a fatty acid becomes fully saturated after reacting with 0.263 g of H₂.

The fatty acid is

• oleic acid (M = 282 g mol⁻¹).

• linolenic acid (M = 278 g mol⁻¹).

• arachidic acid (M = 312 g mol⁻¹).

• arachidonic acid (M = 304 g mol⁻¹).

The diagram to the left represents a section of an enzyme.

The diagram can be described as a

• secondary structure consisting of glutamine, glycine and lysine.

• primary structure consisting of asparagine, glycine and lysine.

• secondary structure consisting of asparagine, alanine and lysine.

• primary structure consisting of glutamine, alanine and lysine.

Which one of the structures shown to the left represents a zwitterion of a 2-amino acid?

• Structure A

• Structure B

• Structure C

• Structure D