plumiBiological molecules: OCR A‑Level Biology A questions
Every OCR A-Level Biology A exam question on 2.1.2 Biological molecules, 2016–2025, with its mark scheme and examiner’s report.
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Q1(a)
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Q1(b)
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Q1(c)
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Q16(a)
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Q16(b)
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Q16(c)(i)
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Q5(d)
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Q24(a)(i)
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All 172 questions on Biological molecules, as a list
- June 2025, Paper 1, Q1 (1 mark): Which option describes a function of inorganic ions? Ca2+ is pumped across the membrane of a neurone to establish the resting potential. A Cl– and HCO3 – are in
- 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, Q4 (1 mark): Which option describes the structure of biological molecules? A Carbohydrates contain only C, H and O, usually with an H to O ratio of 2 : 1. B Nucleic acids co
- June 2025, Paper 2, Q1 (1 mark): Hydrogen bonds are important for the physical and chemical properties of water. How do hydrogen bonds form in water? Electronegative (δ–) oxygen atoms are attra
- June 2025, Paper 2, Q2 (1 mark): Water has many properties that are important for living organisms. Which property of water molecules explains why small animals, such as pond skaters, are able
- June 2025, AS Paper 1, Q4 (1 mark): A student carries out a non-reducing sugar test on a sample of fruit juice. What is the correct reason for heating the sample with hydrochloric acid? A It break
- June 2025, AS Paper 1, Q5 (1 mark): A student is finding out the concentration of a sample of protein. • They set up five solutions that have a range of different protein concentrations. • They ca
- June 2025, AS Paper 1, Q9 (1 mark): Which row of the table correctly compares the properties of glycogen and amylose? Glycogen Amylose A Branched Branched B Insoluble Soluble C Insoluble Insoluble
- June 2025, AS Paper 2, Q1(a) (3 marks): The table describes features of molecules. Complete the table. Use ticks (3) to identify if the feature describes starch or cellulose. Description Starch Cellul
- June 2025, AS Paper 2, Q1(b) (2 marks): Students complete paper chromatography on carbohydrates. The table shows the Rf values for known carbohydrates. © researchgate.net, ResearchGate. Item removed d
- June 2025, AS Paper 2, Q1(c) (2 marks): Outline the role of the solvent in paper chromatography. [2]
- June 2024, Paper 1, Q1 (1 mark): Which statement about lipids is correct? A Lipids are polar molecules. B Lipids that contain fatty acids with carbon–carbon double bonds are liquid at room temp
- June 2024, Paper 1, Q2 (1 mark): Lipids, polysaccharides, nucleic acids and proteins are all macromolecules. Which statement about macromolecules is correct? A All macromolecules are formed in
- June 2024, Paper 1, Q16(a) (3 marks): The table lists some biological molecules. Complete the table by putting a tick (✓) in the appropriate box or boxes on each line to show whether the correspondi
- June 2024, Paper 1, Q16(b) (2 marks): Describe the bond between the two glucose monomers in maltose. [2]
- June 2024, Paper 1, Q16(c)(i) (2 marks): Complete the equation for the conversion of maltotriose to glucose. CH2OH CH2OH CH2OH CH2OH O O O O H H H H H H H H H + 3 OH H OH H OH H OH H HO OH HO OH O O H
- 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, Q9 (1 mark): Lactose is a carbohydrate. Which feature describes the structure of lactose? A Lactose contains glycosidic bonds that are broken by a condensation reaction B La
- June 2024, AS Paper 1, Q10 (1 mark): The diagram shows a triglyceride molecule found in sunflower oil. O O O O O O Which option describes the structure of this triglyceride molecule? A Contains pho
- 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 2024, AS Paper 2, Q6(b) (2 marks): Which statements about biological molecules are true and which are false? Tick (✓) one box in each row. Statement True False Breaking one ester bond in a trigly
- June 2023, Paper 1, Q1 (1 mark): Which description of biological molecules is correct? A DNA and RNA are both polymers of nucleotides. B Hydrolysis of sucrose produces fructose and β-glucose. C
- June 2023, Paper 1, Q2 (1 mark): Which statement about lipids is correct? A Phospholipids are formed by esterification of glycerol with three molecules of fatty acid. B Phospholipids containing
- 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, Paper 2, Q10 (1 mark): Which of the molecules contains the highest proportion of 1-6 glycosidic bonds? A Amylopectin B Amylose C Cellulose D Glycogen Your answer [1]
- June 2023, Paper 2, Q11 (1 mark): Which of the molecules is not used for energy storage? A Amylopectin B Amylose C Cellulose D Glycogen Your answer [1]
- June 2023, Paper 2, Q21(c)(i) (3 marks): Write on the diagram to show the complete structure of alpha glucose. [3]
- June 2023, Paper 2, Q21(c)(ii) (2 marks): Explain how the structure of glucose allows it to move from the plant to the bacterium. [2]
- June 2023, Paper 3, Q2(a)(i) (1 mark): Most vitamins are colourless. Suggest one method for visualising the vitamins in TLC. [1]
- June 2023, Paper 3, Q2(a)(ii) (2 marks): The results of the TLC are shown in the chromatogram in Fig. 2.1. Fig. 2.1 Solvent front Vitamin B6 Vitamin B1 Vitamin B2 Vitamin C Origin Use Fig. 2.1 to calcu
- June 2023, AS Paper 1, Q11 (1 mark): Which statement is a correct description of polymers? A A polymer is broken down by condensation reactions. B A polymer is formed when two monomers bond togethe
- 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, Q13 (1 mark): Which description of the structure of a glucose molecule is correct? A It contains 5 OH groups and has a C:O ratio of 1:1. B It contains 6 OH groups and has a C
- June 2023, AS Paper 1, Q14 (1 mark): Which description of the structure of cellulose is correct? A Alternate α-glucose monomers rotate 180° B Branched polymer forms from β-glucose monomers C Hydrog
- 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 1, Q23(b)(i) (2 marks): Use the chromatogram to calculate the Rf value of valine. Rf = [2]
- June 2023, AS Paper 1, Q23(b)(ii) (1 mark): Serine and leucine have different R groups. With reference to the chromatogram, suggest what can be concluded about the chemical properties of the R groups in s
- June 2023, AS Paper 1, Q28(b) (4 marks): Starch and glycogen are polysaccharides. Starch is present in plant cells, and glycogen is present in animal cells. Glucose is a monosaccharide present in both
- June 2023, AS Paper 2, Q3(a)(i) (1 mark): The above test would not detect the presence of protein in the sample. State the change that needs to be made to this test to enable protein to be detected. [1]
- June 2023, AS Paper 2, Q3(a)(ii) (2 marks): Sodium hydroxide is a white solid ionic compound which is highly soluble in water. It consists of anions and cations. Complete the table below. State the chemic
- June 2023, AS Paper 2, Q3(b) (6 marks): (b)* The students were provided with another sample of an unknown liquid. They carried out chemical tests on this sample to determine what biological molecules
- June 2023, AS Paper 2, Q3(c)(i) (3 marks): The students were then asked to carry out an experiment to determine the glucose concentration of another test solution using a colorimeter. Describe how the st
- June 2023, AS Paper 2, Q3(c)(ii) (2 marks): The students plotted their results, shown in the graph. 80 70 60 50 40 Absorption (%) 30 20 10 0 0 0.001 0.002 0.003 0.004 0.005 0.006 Glucose concentration (mm
- 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 1, Q1 (1 mark): Which statement describes the properties or functions of cholesterol? A It increases the fluidity of the phospholipid bilayer at high temperatures. B It is an u
- June 2022, Paper 1, Q2 (1 mark): Which statement describes triglycerides? A They are broken down by condensation reactions. B They are polymers of glycerol and fatty acids. C They contain ester
- June 2022, Paper 1, Q17 (6 marks): 17* The thermal properties of water allow organisms to live in an environment with relatively small changes in temperature. These properties also make water eff
- 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, Q9 (1 mark): Cellulose is the main component of plant cell walls. Which option is not a property of cellulose? A High tensile strength B Inflexible C Insoluble in water D Re
- June 2022, Paper 2, Q10 (1 mark): Glycogen is a large polysaccharide. Which option describes the structure and function of glycogen? A 1–6 glycosidic bonds are more accessible to enzymes than 1–
- 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, Paper 2, Q21(d)(i) (4 marks): A colorimeter can be used, along with biuret reagent, to determine the concentration of protein in a solution. Outline how to use a colorimeter to determine the
- June 2022, Paper 2, Q21(d)(ii) (1 mark): State one alternative method for determining the concentration of protein in a solution. [1]
- June 2022, AS Paper 1, Q4 (1 mark): The table shows the chemical symbols for some inorganic ions involved in biological processes. Ammonium ion Calcium ion Nitrate ion + Ca+ – A NH4 NO2 – Ca2+ – B
- June 2022, AS Paper 1, Q20 (1 mark): An enzyme hydrolyses a phospholipid molecule to release a fatty acid. What is the name of the bond that is broken in this hydrolysis reaction? A Ester B Glycosi
- 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
- June 2022, AS Paper 1, Q25(a)(i) (3 marks): Draw two water molecules and label the bond between the two molecules. [3]
- June 2022, AS Paper 1, Q25(a)(ii) (3 marks): Explain how the properties of water are related to the transport role of water in a stem. [3]
- June 2022, AS Paper 2, Q3(a)(i) (2 marks): Name the type of bond broken by the enzyme lactase and describe what happens when this bond is broken. [2]
- June 2022, AS Paper 2, Q3(b)(i) (1 mark): Describe how the structure of a polyunsaturated triglyceride molecule would differ from the molecule shown in Fig. 3.2. [1]
- June 2022, AS Paper 2, Q3(b)(ii) (3 marks): Hypercholesterolemia is a condition in which an individual has a high blood cholesterol level. Studies were carried out in the USA over several decades, looking
- 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 2021, Paper 3, Q3(a) (2 marks): Callose is formed from β-glucose monomers. The figure below shows a section of callose. OH O CH2OH HO O O carbon 1 CH2OH CH2OH CH2OH CH2OH CH2OH O O O O O HO HO
- November 2021, Paper 3, Q4(a) (2 marks): Some organisms use a disaccharide called trehalose as a respiratory substrate. Trehalose has a similar structure and very similar chemical properties to sucrose
- November 2021, Paper 3, Q5(a) (1 mark): Amylose is formed from the glucose molecules produced in photosynthesis. Table 5.1 shows three statements about amylose, which may be true or false. Complete Ta
- November 2021, AS Paper 1, Q8 (1 mark): The molecule below is the disaccharide sucrose. CH2OH CH2OH O O H H H H OH H H OH O CH2OH HO H OH OH H Which row, A to D, shows the type of reaction that occurs
- November 2021, AS Paper 1, Q9 (1 mark): Sucrase is the enzyme that breaks down sucrose. Which of the bonds, A to D, is broken by sucrase? A alpha glycosidic B beta glycosidic C ester D peptide Your an
- November 2021, AS Paper 1, Q20 (1 mark): A student carried out four tests on samples from a beaker of starch and amylase. Which row, A to D, would show the correct results if the reaction was still hap
- November 2021, AS Paper 2, Q1(a)(i) (1 mark): State one property of glucose that allows it to be easily transported in animals. [1]
- November 2021, AS Paper 2, Q1(a)(ii) (3 marks): Explain how the structure of glycogen differs from that of amylopectin to make it better suited as an energy store in animals. [3]
- November 2021, AS Paper 2, Q1(a)(iii) (1 mark): Fig. 1.1 shows the molecular structure of beta glucose. CH2OH O H OH H OH H HO H H OH Fig. 1.1 Describe how the structure of alpha glucose would be different fr
- November 2021, AS Paper 2, Q1(b) (1 mark): Fig. 1.2 shows the start of the ring structure of ribose. Complete the diagram to show the position of the carbon atoms. There is no need to include the –H and
- November 2020, Paper 2, Q10 (1 mark): Which of the following reactions, A to D, describes the conversion of a polymer to a monomer? esterification fatty acids and glycerol → triglyceride A condensat
- November 2020, Paper 2, Q20(b)(i) (3 marks): In plants the glucose produced by photosynthesis is changed into starch for storage. Glucose and starch are both carbohydrates. ()Ctamplete the table below to s
- November 2020, Paper 2, Q20(b)(ii) (1 mark): Carbohydrates contain only the elements carbon, hydrogen and oxygen. Polypeptides contain carbon, hydrogen, oxygen and nitrogen. Name one other element present
- November 2020, Paper 3, Q3(b) (2 marks): The solution in which the seedlings were grown contained various dissolved ions. The table below lists two of the functions of these ions in the seedlings. Comp
- November 2020, AS Paper 1, Q15 (1 mark): Which of the rows, A to D, contains the correct elements that are found in proteins? carbon hydrogen oxygen phosphorus nitrogen sulphur A 3 3 3 B 3 3 3 3 3 C 3
- November 2020, AS Paper 1, Q16 (1 mark): Oleic acid is a monounsaturated fatty acid found in vegetable oil. Which of the following, A to D, is the correct structure for oleic acid? A HO O B HO O C HO O
- November 2020, AS Paper 1, Q18 (1 mark): Human pancreatic lipase breaks the bonds between fatty acids and glycerol. What name is given to this reaction? A condensation B esterification C hydration D hy
- 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 1, Q22(b) (3 marks): Outline the method of chromatography that will separate the main amino acids in collagen. [3]
- November 2020, AS Paper 1, Q22(c)(i) (2 marks): Calculate Rf values for the two highest concentration amino acids. Rf value 1 = Rf value 2 = [2]
- November 2020, AS Paper 1, Q22(c)(ii) (2 marks): The table shows the Rf values of a range of amino acids. amino acid Rf value glutamine 0.13 glycine 0.27 isoleucine 0.72 leucine 0.73 methionine 0.55 phenylalan
- 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
- November 2020, AS Paper 2, Q2(c)(ii) (2 marks): The process of esterification leads to the formation of ester bonds during the production of triglycerides. Describe what is meant by the term esterification. [
- 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, Q17(c)(i) (1 mark): Name a type of food molecule that the student will not be able to detect using these chemical tests. [1]
- June 2019, Paper 1, Q17(c)(ii) (2 marks): The table below is a summary of some of the student’s findings. Complete the table by writing in the missing observations and conclusions. Tube Observation Conc
- June 2019, Paper 1, Q17(c)(iii) (1 mark): The student then used a colorimeter to measure the absorbance of the contents of Tube 2. Explain how the use of a colorimeter could improve the student’s conclu
- 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, Paper 2, Q16(d) (3 marks): Water has many properties that are essential for living organisms. Explain how properties relating to the density of water contribute to the survival of organis
- June 2019, Paper 2, Q21(a)(i) (2 marks): Calculate the number of phospholipid molecules in the outer surface of the lipoprotein shown in Fig. 21. Assume that the pattern of proteins and phospholipids s
- June 2019, Paper 2, Q21(a)(ii) (1 mark): Lipoproteins with fewer phospholipids and more protein in the outer layer are known as high density lipoproteins. Lipoproteins with a larger number of phospholi
- June 2019, Paper 2, Q21(b) (6 marks): Complete the passage by choosing the most appropriate word from the list. bile carbon hydrogen insoluble nitrogen oxygen permeability production solid soluble s
- June 2019, Paper 2, Q21(c) (2 marks): Triglycerides are a type of lipid molecule that can be broken down during hydrolysis reactions. Using the structure of triglyceride molecules as an example, exp
- June 2019, AS Paper 1, Q5 (1 mark): The structure of a biological molecule is shown below. CH2OH O OH H H H H OH OH Which of the following options, A to D, correctly describes the molecule? A hexo
- 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, Q22(a) (3 marks): Table 22 is a list of practical apparatus used in biological investigations. Each piece of apparatus has been assigned a letter. Letter Apparatus A calorimeter
- June 2019, AS Paper 1, Q22(b)(i) (1 mark): Describe how a colorimeter is calibrated. [1]
- June 2019, AS Paper 1, Q22(b)(ii) (1 mark): Why is it important to calibrate a colorimeter? [1]
- 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 2019, AS Paper 1, Q25(b)(ii) (2 marks): Lysozyme is also known as a glycoside hydrolase. Suggest the type of chemical bond that lysozyme breaks and name the molecule other than the substrate that is n
- June 2019, AS Paper 2, Q1(a)(ii) (4 marks): Separate samples of the sap were tested for the presence of glucose, starch and sucrose. Using Table 1, complete the following passage, using the most appropria
- June 2019, AS Paper 2, Q1(b)(i) (1 mark): Explain why starch is not transported in the sap. [1]
- June 2018, Paper 1, Q2 (1 mark): The following are a series of organic molecules and the chemical processes that occur to convert them into different molecules. Which of the rows, A to D, is co
- June 2018, Paper 1, Q3 (1 mark): The following table describes the approximate percentage mass of different chemical elements in organic polymers. N C O H P Polymer (%) (%) (%) (%) (%) A nuclei
- June 2018, Paper 1, Q18(b) (3 marks): Plant cell walls are made of cellulose. Cellulose is a polymer of β-glucose. Give three properties of cellulose that make it suitable as the basis of plant cell
- June 2018, Paper 1, Q19(b) (4 marks): Chitin is a polysaccharide found in insects. It is used to form the hard outer casing of their bodies. Fig. 19.2 shows the chemical structure of chitin. CH2OH C
- June 2018, Paper 2, Q4 (1 mark): Which of the following processes involves the formation of ester bonds? 1 synthesis of polynucleotides 2 synthesis of triglycerides 3 synthesis of polypeptides
- 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, Paper 2, Q6 (1 mark): Lipids are a diverse group of chemicals that are neither polar nor charged and hence are insoluble in water. The ___(1)___ nature of the heads of phospholipids
- June 2018, Paper 2, Q22(a) (1 mark): Compound W shows some structural similarities with fatty acids. State one structural difference between compound W and a saturated fatty acid. [1]
- June 2018, Paper 3, Q2(b) (3 marks): Glucose and other carbohydrates are present in respiring cells. The concentrations of carbohydrate molecules vary between tissues. A student conducted tests on
- June 2018, AS Paper 1, Q4 (1 mark): The image below shows isomaltulose, a disaccharide formed from α-glucose and fructose. CH2OH O H H H OH H O HO H O OH H OH H H OH H CH2OH OH H Name the bond tha
- June 2018, AS Paper 1, Q11 (1 mark): The hydroxyl (-OH) group of carbohydrates is polar and makes the molecule soluble in water. The greater the number of free hydroxyl groups as a proportion of th
- June 2018, AS Paper 1, Q19 (1 mark): The table below shows four biological molecules and their component elements. Which of the rows, A to D, correctly identifies the elements in each molecule? suc
- June 2018, AS Paper 1, Q21(b) (2 marks): Outline the properties of water which make it an ideal habitat for an amphibian. [2]
- June 2018, AS Paper 1, Q22(a) (1 mark): On Fig. 22 circle an ester bond. [Answer on Fig. 22] [1]
- June 2018, AS Paper 1, Q22(b) (1 mark): Sunflower oil is used to make biodiesel, which contains methyl esters. The fatty acids in the triglyceride molecule are reacted with methanol in a process calle
- June 2018, AS Paper 1, Q22(c)(i) (3 marks): Name three other functions of triglycerides in living organisms. 1 2 3 [3]
- June 2018, AS Paper 1, Q22(c)(ii) (2 marks): Table 22 shows the melting points of some of the methyl esters made from the transesterification of sunflower oil fatty acids. Methyl ester Formula Melting poin
- 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 2018, AS Paper 2, Q1(c)(i) (4 marks): Describe four ways you would refine the method used by the students. For each change you suggest, give a reason why this would improve the results of the experi
- June 2018, AS Paper 2, Q1(c)(ii) (2 marks): Table 1 shows the Rf values of some amino acids. Name of amino acid Rf value Alanine 0.31 Cysteine 0.40 Glutamine 0.13 Phenylalanine 0.59 Table 1 Using the info
- June 2018, AS Paper 2, Q4(a)(i) (2 marks): Ions have a number of important roles in living organisms. Complete the table below by identifying the ion that plays each of the roles. Choose from the followi
- June 2017, Paper 1, Q18(c)(i) (2 marks): Soluble mineral ions are present in soil. –) ions. Explain why water molecules can form hydrogen bonds with nitrate (NO3 [2]
- June 2017, Paper 2, Q2 (1 mark): Which of the statements, A to D, about amylopectin is correct? A it contains 1-4 and 1-6 glycosidic bonds between α-glucose monomers B it is an unbranched chain
- June 2017, Paper 2, Q20(a)(i) (2 marks): State two other structural similarities between lactose and maltose. 1 2 [2]
- June 2017, Paper 2, Q20(a)(ii) (3 marks): Complete the table below to identify differences between the structures of lactose and maltose. The first one has been completed for you. Lactose Maltose one gl
- June 2017, Paper 2, Q20(b)(i) (3 marks): Explain how the structure of galactose allows it to be used as a respiratory substrate. [3]
- June 2017, Paper 2, Q20(c) (4 marks): Lactose is a reducing sugar. Benedict’s reagent can be used to detect the presence of lactose in a solution. A colorimeter can be used to measure the concentrat
- 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, Q1(a)(ii) (1 mark): Students used thin layer chromatography to separate leucine from other amino acids. The chromatogram they produced is shown in Fig. 1.2. Y X leucine origin solv
- June 2017, Paper 3, Q1(a)(iii) (3 marks): Amino acid Z was in the mixture analysed by the students. It is not shown on the chromatogram in Fig. 1.2. Amino acid Z has an Rf value that is 0.20 lower than
- June 2017, Paper 3, Q1(b)(i) (1 mark): State a material that can be used as the stationary phase in thin layer chromatography. [1]
- June 2017, Paper 3, Q1(c) (3 marks): When sequencing DNA, fragments of DNA are separated by electrophoresis. Describe three differences between the process of thin layer chromatography and the form
- 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
- June 2017, AS Paper 1, Q7 (1 mark): Water is known as the universal solvent as it has the ability to dissolve many ionic and covalent compounds due to its polar nature. Which of the 3-carbon compo
- June 2017, AS Paper 1, Q8 (1 mark): Which of the options, A to D, is a correct statement about polysaccharides of glucose? A Cellulose microfibrils are formed by hydrogen bonding between adjacent
- June 2017, AS Paper 1, Q10 (1 mark): A group of students was given a 1% solution of an unknown digestive enzyme. They were also given three tubes containing an identical mixture of foods. The stude
- June 2017, AS Paper 1, Q22(a) (3 marks): Explain why mammals store glycogen instead of glucose. [3]
- June 2017, AS Paper 2, Q6(a)(i) (3 marks): Plot a graph of the mean % absorbance at each glucose concentration. [3]
- June 2017, AS Paper 2, Q6(a)(ii) (2 marks): The students were provided with three different fruit juices labelled A, B and C. The Benedict’s test was carried out on each fruit juice and samples were prepa
- June 2017, AS Paper 2, Q6(b)(i) (4 marks): Describe how you would carry out a controlled experiment to test this hypothesis without using a colorimeter. [4]
- June 2017, AS Paper 2, Q6(b)(ii) (1 mark): Suggest one reason why the results for this experiment might not support the students’ hypothesis. [1]
- June 2017, AS Paper 2, Q6(c)(i) (2 marks): State two ways in which the molecular structure of cholesterol is similar to the molecular structure of glucose. [2]
- June 2017, AS Paper 2, Q6(c)(ii) (1 mark): Glucose is an important biological molecule required by cells for cellular respiration. State the physical property of glucose that allows it to be easily trans
- June 2016, AS Paper 1, Q2 (1 mark): Carbohydrates, such as starch, are made from monosaccharides joined together. Which of the bonds, A to D, joins monosaccharides together? A ester B glycosidic C
- June 2016, AS Paper 1, Q11 (1 mark): A student investigates some solutions, X, Y and Z, using paper chromatography. The results are shown below. solvent front X Y Z Which of the following options,
- June 2016, AS Paper 2, Q3(a)(i) (1 mark): How does the composition of N-acetylglucosamine differ from the composition of a monosaccharide sugar? [1]
- June 2016, AS Paper 2, Q3(a)(ii) (2 marks): Which monosaccharide sugar does N-acetylglucosamine most closely resemble? [2]
- June 2016, AS Paper 2, Q3(a)(iii) (4 marks): Using your knowledge of the formation of structural polysaccharides, describe the formation of the chitin molecule from its monomer and predict its structure. [
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