Chapter 8 Multiple Choice Questions

. Chelating agents may be used in the treatment of poisoning with metal ions because:

They donate electrons easily and reduce the metal ion to the inactive metal.

They can form dative covalent bonds with metal ions to form complexes.

They contain nitrogen or oxygen atoms which act as Lewis acids by donating electrons.

They can form insoluble salts with the metal ions through formation of ionic bonds

. On her way home from classes Sarah Patel treats herself to some chips. She sprinkles two small sachets of salt onto the chips. If each sachet of salt contains 800mg of sodium chloride how many moles of sodium ions is she consuming?

2.7 x 10^-2 moles

2.7 x 10 moles

6.9 x 10 moles

6.9 x 10^-2 moles

. Sterile Potassium Chloride Concentrate BP is used in an emergency to treat hypokalaemia. The solution must be diluted before I.V. use. The concentration of Sterile Potassium Chloride Concentrate BP is 15% w/v KCl. Calculate the concentration of potassium ions in μmol/ml contained in an I.V. infusion made by diluting 10 ml of Sterile Potassium Chloride Concentrate BP to 500ml with water for Injections.

200

77

40000

40

. Cytochromes involved in respiration;

Utilise iron to carry electrons because of the reaction

Utilise iron to activate water molecules so that they are more effective in hydrolysing peptides.

Require both zinc and iron ions to successfully transport electrons.

. Angiotensin-converting-enzyme (ACE) contains a zinc ion at its active site. Which of the following statements about ACE and ACE inhibitors is correct?

ACE inhibitors contain a group which can interact with ACE through donation of electrons to reduce the zinc ion.

The role of zinc ions in ACE is to act as an electron transfer system though the reaction.

ACE inhibitors contain a group which can interact with ACE through donation of electrons so that they act as a ligand with the zinc ion.

The role of zinc ions in ACE is to interact directly with the nitrogen in the peptide link in angiotensin I to encourage hydrolysis of the bond.

. Cisplatin has its action due to:

The ability of platinum atoms to form complexes with thiol groups.

Replacement of adjacent chlorine atoms on cisplatin with water molecules leaves a positively charged complex.

Precipitation of nano particles of platinum inside cancer cells.

Reduction of platinum ions to platinum.

. Which of the following statements about phosphoric acid derivatives is false?

Codeine phosphate is an example of a phosphate ester which allows oral administration of codeine.

Dexamethasone sodium phosphate is an example of the sodium salt of a phosphate ester and it allows dexamethasone to be formulated as an injection.

The triphosphoric acid group as found in ATP can be considered to be an anhydride.

Phospholipids are diesters of phosphoric acid.

. Bisphosphonates such as alendronic acid can be used to treat osteoporosis because:

In bisphosphonates the phosphorous atoms are trivalent and mammalian enzymes cannot normally react with compounds containing trivalent phosphorous.

Bonding of the phosphorous atom directly to the carbon promotes complex formation with calcium ions.

They are not esters and are therefore not easily hydrolysed, when adsorbed onto hydroxyapatite they reduce the rate of bone turnover.

They form salts with calcium ions in the gastro-intestinal tract and this promotes the absorption of calcium ions.

. The ACE inhibitor Captopril contains a thiol group. Which of the following statements best describes the role of the thiol group?

In thiol groups sulfur has an oxidation number of -2. The thiol is oxidised to a sulfoxide and this reduces the Zn²⁺ ion to Zn, preventing it from activating water molecules.

In thiol groups sulfur has an oxidation number of +2 and the thiol group is able to ionise and form an ionic bond with the Zn²⁺ion in ACE.

In thiol groups sulfur has an oxidation number of +2 and the thiol group is able to form a covalent bond with the Zn²⁺ion in ACE.

In thiol groups sulfur has an oxidation number of -2 and the thiol group is able to interact with Zn²⁺ions through complex formation.

. Which of the following statements about sulfate esters is false?

Sulfate ester metabolites are less polar than the parent hydroxyl drugs and the metabolites can pass readily across phospholipid membranes.

The remaining OH group in sulfate esters will be a strong acid so that sulfate esters will be ionised at physiological pH.

The oxidation state of sulfur in sulfate esters is +6.

Alcoholic and phenolic drugs may be metabolised by sulphate ester formation.

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