plumiProteins: OCR A‑Level Biology A questions
OCR A-Level Biology A past-paper questions on 2.1.2.5 Proteins, 2016–2025, with mark schemes and examiner’s reports where available.
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All 42 questions on Proteins, as a list
- June 2025, Paper 1, Q2 (1 mark): Which option describes a conjugated protein? A A globular protein with a prosthetic group B A protein with an inorganic ion C A protein with more than one polyp
- June 2025, Paper 1, Q21(b) (4 marks): Explain how the structure of haemoglobin allows it to transport oxygen from the lungs to the tissues. [4]
- June 2024, Paper 3, Q5(d) (2 marks): The table lists statements about a molecule of insulin. Complete the table by stating the level of protein structure (primary, secondary, tertiary or quaternary
- June 2024, AS Paper 1, Q24(a)(i) (3 marks): In addition to having a quaternary structure, haemoglobin also has primary, secondary and tertiary structures. The table below contains statements about the str
- June 2024, AS Paper 2, Q6(a)(i) (2 marks): The general structure of an amino acid molecule has one R group and two other groups. Name the two other groups in an amino acid molecule. 1 2 [2]
- June 2024, AS Paper 2, Q6(a)(ii) (1 mark): Below is a diagram of a dipeptide. R1 O H R2 H O N C C N C C H O H H H Draw a circle around the peptide bond. Answer on the diagram. [1]
- June 2024, AS Paper 2, Q6(a)(iii) (1 mark): Name the type of reaction involved in breaking the peptide bond. [1]
- June 2023, Paper 1, Q3 (1 mark): Which statement about the structure of amino acids is not true? A Amino acids contain amino and carboxyl groups. B Amino acids contain the elements hydrogen, ca
- June 2023, Paper 1, Q4 (1 mark): Which of the options is a feature of collagen? A It allows alveoli to recoil B It dissolves in water C It is flexible D It is the main protein found in hair You
- June 2023, AS Paper 1, Q12 (1 mark): A scientist analysed and recorded all of the chemical elements in one particular amino acid. Which elements did the scientist record? A C, H, N, S B C, H, O, N
- June 2023, AS Paper 1, Q23(a) (1 mark): Name and describe the reaction that produces amino acids from polypeptides. [1]
- June 2023, AS Paper 2, Q5(b)(ii) (2 marks): Collagen is a protein found in ligaments. Ligaments attach bone to bone and stabilise joints. State the properties of collagen that make it suitable for this fu
- June 2022, Paper 2, Q8 (1 mark): Which statement about the secondary structure of a protein is correct? A β-pleated sheets contain β-glucose. B Disulfide bonds are not involved. C Each single p
- June 2022, Paper 2, Q16(a)(i) (1 mark): Name the bond present in the primary structure of a protein. [1]
- June 2022, Paper 2, Q16(a)(ii) (1 mark): Name the structure labelled X. [1]
- June 2022, Paper 2, Q16(a)(iii) (1 mark): State one feature, visible in Fig. 16.1, that shows that haemoglobin is a globular protein. [1]
- June 2022, Paper 2, Q21(b)(ii) (2 marks): Both bacteria also break down some of the protein casein, which is present in milk. Name the product of protein breakdown and describe the type of reaction that
- June 2022, AS Paper 1, Q21(a) (3 marks): The amino acid cysteine is abbreviated to ‘CYS’ in Fig. 21.1. The side chain (R group) found in cysteine is shown in Fig. 21.2. Complete Fig. 21.2 to show the s
- June 2022, AS Paper 1, Q21(b) (2 marks): Explain how Fig. 21.1 shows that insulin has a quaternary structure. [2]
- June 2022, AS Paper 1, Q21(c)(i) (1 mark): Suggest why insulin glargine is long-lasting. [1] 14 The table shows some of the DNA triplet codes for amino acids. 1st base 2nd base of DNA triplet 3rd base of
- November 2021, Paper 2, Q1 (1 mark): Which of the options is a function of fibrous proteins? A aids rigidity of membranes B involved in cell signalling C provides elasticity in alveoli D speeds up
- November 2021, Paper 2, Q2 (1 mark): Which of the types of molecule is shown in the diagram? H H O N C C H OH CH2 CH2 CH2 CH2 NH2 A amino acid B fatty acid C nitrogenous base D nucleotide [1] Your
- November 2020, AS Paper 1, Q19 (1 mark): A conjugated protein is held together by many different types of bond. Which bond is not formed when a conjugated protein folds into its quaternary structure? A
- November 2020, AS Paper 1, Q22(a)(i) (3 marks): Describe and explain why collagen is a fibrous protein. [3]
- November 2020, AS Paper 1, Q22(a)(ii) (1 mark): Suggest why collagen is such a strong molecule. [1]
- November 2020, AS Paper 2, Q2(c)(i) (2 marks): A protein is made up of amino acids which are joined by chemical bonds. Below is an incomplete diagram of one of these bonds. Complete the diagram of the molecu
- June 2019, Paper 1, Q13 (1 mark): Collagen is found in tendons. Tendons attach muscles to bones. Which of the following lists of properties, A to D, makes collagen suitable for this role? A stro
- June 2019, Paper 1, Q20(a)(i) (3 marks): Rubredoxin is known as a conjugated protein. Use Fig. 20.1 to explain what is meant by the term conjugated protein. [3]
- June 2019, Paper 1, Q20(a)(ii) (2 marks): Using the information provided about rubredoxin, state two similarities between the structures of rubredoxin and haemoglobin. similarity 1 similarity 2 [2]
- June 2019, Paper 1, Q20(a)(iii) (2 marks): Rubredoxin and haemoglobin have different secondary and tertiary structures. Using the information provided about rubredoxin, state two other differences betwee
- June 2019, Paper 1, Q20(b)(i) (3 marks): Ferritin molecules can hold 4500 Fe3+ ions in the inner sphere. It is thought that the Fe3+ ions are unable to occupy the total available volume of the inner sp
- June 2019, Paper 1, Q20(b)(ii) (1 mark): Explain how hydrophilic and hydrophobic interactions contribute to the spherical shape of ferritin. [1]
- June 2019, AS Paper 1, Q6 (1 mark): Which of the following molecules, A to D, could be a product of breaking a peptide bond during a hydrolysis reaction? A B H H O H O H C C N C C N HO H H H CH CH
- June 2019, AS Paper 1, Q25(a)(i) (1 mark): Name the covalent chemical bond labelled X which links two cysteine amino acids. [1]
- June 2019, AS Paper 1, Q25(a)(ii) (1 mark): Name the structure labelled Y which forms part of the secondary structure of lysozyme. [1]
- June 2019, AS Paper 1, Q25(a)(iii) (1 mark): Lysozyme consists of a single polypeptide chain of 129 amino acids. State which level of protein structure is not shown by lysozyme. [1]
- June 2018, Paper 2, Q5 (1 mark): Which of the following could not be an amino acid? A B NH NH2 O HO HO OH O O NH2 C D OH NH2 O HO H2N OH OH Your answer [1]
- June 2018, AS Paper 2, Q1(a)(i) (1 mark): State the names of the groups labelled U and V. U V [1]
- June 2018, AS Paper 2, Q1(a)(ii) (1 mark): Fig. 1.2 shows a representation of a short polypeptide chain made from three amino acids. Valine Bond W Alanine Glycine Fig. 1.2 Name bond W and state what type
- June 2018, AS Paper 2, Q1(b)(iii) (6 marks): (iii)* Titin is a fibrous protein. Pepsin is a globular protein. Compare the properties and functions of fibrous proteins and globular proteins in the human bod
- June 2017, Paper 3, Q1(a)(i) (1 mark): On Fig. 1.1, draw a circle around the R group of leucine. H H3C C CH3 CH2 H2N C COOH H Fig. 1.1 [1]
- June 2017, Paper 3, Q2(a)(i) (2 marks): The table below contains statements about the structures of gluten polypeptides. In the boxes next to each statement, write the level of protein structure (prim
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