MDCAT Chemistry chapter 19: Chemistry · Macromolecules MCQs with answers
By Team Megalecture · Updated 4 Nov 2026
48 exam-style questions on Chemistry · Macromolecules, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.
Ten Chemistry · Macromolecules questions with answers
Try each one, then open the answer. These ten stay the same; the test draws new ones every time.
1. The primary structure of a protein, its sequence of amino acids, is held together by
A
hydrogen bonds between C=O and N–H groups
B
covalent peptide bonds
C
disulphide bridges between side chains
D
ionic bonds between charged side chains
Show answer
Answer: B. The amino acids of the chain are joined in order by covalent peptide (amide) bonds, which only hydrolysis breaks. Hydrogen bonds between C=O and N–H shape the secondary structure, and disulphide bridges and ionic bonds help hold the tertiary structure.
2. A polymer has the repeating unit –CH2–CH(CN)–. Its monomer is
A
CH3CH2CN
B
NC–CH=CH–CN
C
CH2=CHCN
D
CH2=CHCl
Show answer
Answer: C. The repeating unit of an addition polymer is the monomer with its C=C opened, so the monomer is acrylonitrile, CH2=CHCN, and the polymer is polyacrylonitrile (Orlon). CH3CH2CN has no double bond and cannot polymerise by addition.
3. Which change alters the primary structure of a protein?
A
hydrolysing one of its peptide bonds
B
breaking the hydrogen bonds of an α-helix
C
breaking ionic links between its side chains
D
separating the polypeptide subunits of the protein
Show answer
Answer: A. Primary structure is the order of amino acids linked by peptide bonds, so hydrolysing a peptide bond changes it. Hydrogen bonds hold the secondary structure, ionic links the tertiary structure, and the grouping of subunits is the quaternary structure.
4. Which sugar does not reduce Fehling's solution?
A
sucrose
B
glucose
C
fructose
D
maltose
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Answer: A. In sucrose, glucose and fructose are joined through both of their reducing (carbonyl) carbons, so no free aldehyde or ketone group remains. Glucose, fructose and maltose each keep a free reducing group.
5. The iodine number of an oil or fat is the mass of iodine, in grams, taken up by 100 g of it. A high iodine number shows that the oil
A
contains much free fatty acid
B
has short fatty acid chains
C
is highly unsaturated
D
is fully saturated
Show answer
Answer: C. Iodine adds across C=C double bonds, so the more C=C bonds the fatty acid chains contain, the more iodine is taken up. Liquid oils have higher iodine numbers than solid fats; free fatty acid is measured by the acid number instead.
6. The enzyme urease catalyses the reaction of urea, CO(NH2)2, with water. The products are
A
NH4CNO only
B
NH3 and CO2
C
N2 and CO2
D
NH3 and CO
Show answer
Answer: B. Urease hydrolyses urea: CO(NH2)2 + H2O → 2NH3 + CO2. Ammonium cyanate is an isomer of urea, not a hydrolysis product, and no redox change takes place to give N2 or CO.
7. What is the percentage by mass of chlorine in PVC, made by addition polymerisation of CH2=CHCl? (H = 1, C = 12, Cl = 35.5)
A
59.7%
B
56.8%
C
57.7%
D
16.7%
Show answer
Answer: B. No atoms are lost in addition polymerisation, so PVC has the same composition as its monomer, C2H3Cl (Mr = 62.5): 35.5 ÷ 62.5 × 100 = 56.8%, whatever the chain length. Leaving out the hydrogen atoms gives 59.7%, and 16.7% is simply one atom in six.
8. Nylon-6,6 is made from hexanedioic acid (adipic acid) and
A
ethane-1,2-diol
B
benzene-1,4-dicarboxylic acid
C
caprolactam
D
hexane-1,6-diamine
Show answer
Answer: D. The –NH2 groups of hexane-1,6-diamine (hexamethylenediamine) react with the –COOH groups of adipic acid to form amide links; each monomer has six carbons, hence '6,6'. Ethane-1,2-diol and benzene-1,4-dicarboxylic acid make the polyester Terylene.
9. The monomer from which polystyrene is made by addition polymerisation is
A
C6H5CH2CH3
B
C6H5CH=CH2
C
C6H6
D
CH2=CHCl
Show answer
Answer: B. Polystyrene is the addition polymer of styrene (phenylethene), C6H5CH=CH2, whose C=C bond opens to link the units. Ethylbenzene, C6H5CH2CH3, has no C=C and cannot add on, and CH2=CHCl gives PVC.
10. Ceruloplasmin is a blood plasma protein that carries copper around the body. By function it is classed as
A
a structural protein
B
a hormonal protein
C
a transport protein
D
a contractile protein
Show answer
Answer: C. Proteins that carry substances in the body, such as haemoglobin (oxygen) and ceruloplasmin (copper), are transport proteins. Structural proteins such as collagen and keratin give strength, and contractile proteins such as myosin bring about movement.
Chemistry · Macromolecules: questions students ask
How many Chemistry · Macromolecules MCQs are there?
48, each with the answer and a short explanation, across 2 topics: Polymers, Biological macromolecules. Every chapter test draws ten of them, so you can take it many times.
Is the MDCAT Chemistry chapter 19 test free?
Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.
How is the chapter test marked?
The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.
