48 exam-style questions on Proteins — topic B1.2 of Form and function in the IB Biology syllabus — with answers and explanations. Samples below; the full set is free with an account.
The monomers from which proteins are built are
Answer: amino acids
Amino acids join by peptide bonds (condensation) to form polypeptides.
State the type of bond that links adjacent amino acids in the primary structure of a protein.
Answer: Peptide bond
Amino acids are joined by peptide bonds, formed by condensation between the amino group of one and the carboxyl group of the next.
Determine what distinguishes one amino acid from another.
Answer: The variable R group
All amino acids share an amino group, a carboxyl group and a central carbon; only the variable R group differs, giving each amino acid its properties.
Which bond between R groups helps stabilise the tertiary structure of a globular protein containing cysteine residues?
Answer: Covalent disulfide bridges
Tertiary structure is stabilised by R-group interactions, including strong covalent disulfide bridges between the sulfur-containing R groups of cysteine residues.
Explain why boiling an egg white causes it to become solid and opaque.
Answer: Proteins denature and unfold
Heat disrupts the hydrogen bonds, ionic bonds and other interactions maintaining tertiary/quaternary structure, so proteins denature, unfold and aggregate; the primary sequence is unchanged.
Distinguish fibrous from globular proteins by determining which statement is correct.
Answer: Fibrous proteins are structural, insoluble; globular soluble
Fibrous proteins (e.g. collagen) are elongated, structural and insoluble; globular proteins (e.g. enzymes, haemoglobin) are compact, usually water-soluble and have metabolic/functional roles.
That was 6 of 48 Proteins questions.
Practise all 48 freeStateAO1 · 1–2 marks
One word or one short sentence. No explanation, no working: the mark is for the fact itself.
OutlineAO2 · 1–4 marks
A brief account or summary: the main points in two or three sentences, no evaluation.
DetermineAO3 · 3–8 marks
Obtain the only possible answer — by calculation, from the graph or by reasoning — and show how.
48 Proteins questions — free with an account. Spaced repetition, streaks and full exam simulations included.
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