Biological molecules — AS & A Level Biology (9700) questions by topic

The iodine test and the Benedict's test were carried out on samples of a starch solution. Amylase was added to another sample of the starch solution and incubated for 10 minutes.…

Which row about α-glucose and β-glucose molecules is correct? carbon atom on which the OH position is different cellulose contains both molecules --- --- --- A 1 no B 1 yes C 4 no…

Which molecules are monosaccharides? 1 ribose 2 glucose 3 deoxyribose 4 sucrose A 1, 2 and 3 B 1, 2 and 4 C 1, 3 and 4 D 2, 3 and 4

Many animals use triglycerides for long-term energy storage. Which statements are correct additional functions of triglycerides? 1 They provide buoyancy in some marine animals. 2…

The diagrams show three different bonds. Bond 1: —NH····O— (hydrogen bond between NH and O) Bond 2: —C(=O)—N—H (peptide bond) Bond 3: —CH₂—S—S—CH₂— (disulfide bond) Which bonds…

What describes the quaternary structure of a collagen molecule? A polypeptides that form an α-helix, which are held together by covalent bonds B polypeptides that form a double…

The diagram shows the structure of the enzyme amylase. Which level of protein structure results in the folding of amylase into its globular shape? A primary B secondary C tertiary…

Which statement explains why large volumes of water maintain a constant temperature when the air temperature increases? A The latent heat of vaporisation of water is high. B The…

A sample of a solution of sucrose tested for reducing sugars remains blue, but when another sample of the same solution is tested for non-reducing sugars the solution turns red.…

Which molecules contain at least two double bonds? A Venn diagram shows three overlapping circles labelled 'saturated triglyceride', 'collagen', and 'haemoglobin'. Regions A, B,…

Amylose, amylopectin and glycogen are all polysaccharides. Enzyme X removes one maltose molecule at a time from the ends of a polysaccharide molecule by hydrolysis of…

Which property of water enables sweating to be an efficient means of losing heat from the body? A The latent heat of vaporisation of water is high. B The specific heat capacity of…

Which bonds are found in the levels of structure of a protein molecule? primary structure secondary structure quaternary structure --- --- --- --- A covalent bond hydrogen bond…

The diagram shows the structure of a virus. What do labels 1 and 2 identify? 1 = capsid; 2 = phospholipid envelope A 1 = capsid; 2 = phospholipid envelope B 1 = phospholipid…

Which statement about macromolecules is correct? A Cellulose is a branched polymer of glucose monomers. B DNA is composed of two polymers of nucleotide monomers. C Glycogen is an…

Sucrose is heated with dilute acid. Which statement describes what happens? A Sucrose is oxidised to form glucose and galactose. B Sucrose is hydrolysed to form two glucose…

A student classifies three polymers P, Q and R. P = glycogen, Q = amylopectin, R = energy storage polymer Which row is correct? A P = amylose, Q = glycogen, R = cellulose B P =…

A carboxyl group is released on hydrolysis of which molecules? 1 phospholipids 2 proteins A 1 only B 1 and 2 C 2 only D neither 1 nor 2

Which bonds are found in the secondary structure (1) and tertiary structure (2) of a protein? A 1 = hydrogen bonds only; 2 = hydrogen, ionic and disulfide bonds B 1 = hydrogen…

Which two amino acids have no overall charge at pH 7? A aspartate and glutamate B alanine and glycine C lysine and arginine D aspartate and lysine

Which property of water allows it to undergo only small temperature changes when heat energy is added or removed? A high latent heat of vaporisation B high specific heat capacity…

An enzyme has histidine on its surface and proline inside. Which statement correctly explains this arrangement? A Histidine is hydrophobic and proline is hydrophilic. B Histidine…

Boiled diastase is added to a starch solution. What would be observed when iodine solution and Benedict's reagent are added? A iodine = blue-black; Benedict's = blue B iodine =…

Which substance is required for sucrose hydrolysis? A amylase B maltase C hydrochloric acid D sodium hydroxide

A Venn diagram has three overlapping circles: unsaturated fatty acid, collagen, haemoglobin. A molecule with at least two carbon-carbon double bonds would be in which region? A…

Which statement about globular proteins is correct? A They are insoluble in water. B They all have quaternary structure. C They can change shape using energy from ATP. D They all…

Which diagram correctly shows a hydrogen bond between two water molecules? A [diagram showing H-bond between H of one molecule and O of another] B [diagram showing H-bond between…

A detergent disrupts hydrogen bonds in water. What effect would this have on the specific heat capacity and latent heat of vaporisation of water? A both decrease B specific heat…

Amylose and the triglyceride stearin are macromolecules. Explain why amylose and stearin are macromolecules, but only amylose is a polymer.

Fig. 3.1 shows the structure of galactose. Describe one difference between the structure of galactose shown in Fig. 3.1 and the structure of glucose.

Bees are insects that produce venom as a means of self-defence. Melittin is a polypeptide present in the venom of bees. Lysine is one of the amino acids present in melittin. Fig.…

The human pancreas synthesises and secretes a number of different digestive enzymes. These enzymes have their effect in the small intestine. Pancreatic lipase acts by breaking the…

What is the maximum number of hydrogen bonds that can form between a single water molecule and other water molecules?

The diagrams show the structure of four amino acids in aqueous solution: glycine (R group is H, with COO- and N+H3 groups); lysine (R group is a -CH2-CH2-CH2-CH2-N+H3 chain, with…

The table shows the number of carbon atoms and the number of carbon-carbon double bonds in molecules of three triglycerides and the fatty acids they contain. The information is…

Collagen molecules are made up of three polypeptide chains interacting together. The individual polypeptide chains consist of a regular pattern of amino acids. Almost every third…

The masses of the parts of haemoglobin are shown in the table: alpha-globin chain 15126 Da; beta-globin chain 15868 Da; haem group 617 Da. A haemoglobin molecule contains two…

Which row is correct for cellulose? The columns are 'rotation of alternate monomers by 180 degrees', 'shape of molecule' and 'hydrogen bonds between molecules'. (key: tick =…

Which statements about peptide bond formation are correct? (1) The bond formation occurs between a carbon of one amino acid and a nitrogen of the next amino acid after the amino…

Tests for biological molecules were carried out on three solutions. Each solution contained only one type of biological molecule. The observations were: solution 1 - Benedict's…

Which row correctly identifies the weak and strong bonds in the tertiary and quaternary structure of a typical protein? The columns are the bond types: disulfide, hydrogen,…

Which row correctly describes haemoglobin? Each row gives four statements about haemoglobin structure and function.

Which statements describe features of cellulose that adapt it for its function in plant cells? 1 Three cellulose molecules coil around each other to form a triple helix structure.…

Which structure shows alpha-glucose? The question shows four ring (pyranose) structural formulae of glucose, labelled A, B, C and D. Options A and B are drawn in the standard…

What cannot occur as a result of a condensation reaction? A breaking of a glycosidic bond B formation of a disaccharide C joining together of two amino acids D production of a…

Which fact about the quaternary structure of proteins is correct? A consists of four polypeptides B depends on the presence of metal ions C depends on the primary structure of the…

Which properties of water are dependent on hydrogen bonding between water molecules? The table uses a key: a tick means the property is dependent on hydrogen bonding, a cross…

Water is the main component of blood. Explain how the properties of water make it suitable as the main component of blood.

In the mesophyll tissue of leaves, products of photosynthesis can be used to synthesise organic compounds, such as the polysaccharide cellulose and some amino acids. A source of…

Collagen is a fibrous protein that is found in many tissues in animals. Describe the structure of a collagen molecule and the structure of a collagen fibre.

A naturally occurring polysaccharide synthesised in a plant is a branched chain of alpha-glucose. The straight parts of the molecule are linked by alpha-1,6 glycosidic bonds with…

The diagram shows a triglyceride. The triglyceride has three fatty acid chains esterified to glycerol: the top chain is a fully saturated chain with no carbon-carbon double bonds,…

The diagram shows how the alternating nature of beta-glucose monomers along a chain allows hydrogen bonds to form between consecutive monomers within a single cellulose molecule.…

Two solutions, 1 and 2, each contained a mix of two different biological molecules. One solution contained starch and sucrose, and the other contained glucose and protein. The two…

The diagrams show parts of three pairs of amino acids within a protein. The pairs are labelled X, Y and Z. Pair X shows two groups, each a carbon bonded to two H atoms and an -O-H…

The diagram shows part of a collagen fibril made of collagen triple helices. The collagen triple helices are linked to each other by one type of bond. This bond is labelled as X…

The table shows some information about the polypeptides that make up haemoglobin. For alpha-globin: total number of amino acid residues in the polypeptide chain = 141, position of…

Which feature of glycogen distinguishes it from starch?

The diagram shows a biological molecule. The molecule is drawn as a glycerol backbone (three carbons each shown with hydrogens) with three long hydrocarbon fatty acid chains…

Which molecules are globular proteins? 1 amylase; 2 haemoglobin; 3 DNA polymerase.

Phospholipids are formed in a similar way to triglycerides. A sample contained six phospholipid molecules. The molecular weight of a phosphate ion is 95 g/mol. The molecular…

The diagram shows a triglyceride. The triglyceride has a glycerol backbone with three fatty acid chains: the top two chains are fully saturated hydrocarbon chains with no…

Which description lists all the components of a human haemoglobin molecule?

HIV-1 protease is an enzyme produced by the HIV virus. Two identical chains of 99 amino acids form the enzyme. In each chain, amino acids 25, 26 and 27 in the sequence form part…

Which statements are correct reasons for how animals cool down in hot environments using latent heat of vaporisation of water? 1 Some animals lie down and roll in wet soil. 2 Fish…

Which statements could be used to describe enzyme molecules and antibody molecules? 1 Hydrogen bonds stabilise the structure of the protein and are important for it to function…

Which row is correct for parts of a phospholipid molecule? Row can be saturated or unsaturated can also be found in a triglyceride --- --- --- A head tail B tail head C head head…

Fig. 4.1 shows the structure of sucrose, a disaccharide produced by plant cells (an alpha-glucose ring joined to a fructose ring by an oxygen bridge). Name the covalent bond that…

The olive plant, Olea europaea, is grown in many parts of the world. The fruits of the plant (olives) and the oil that can be obtained from the fruits (olive oil) provide food for…

Cysteine is an amino acid containing sulfur. Fig. 2.1 shows the structure of the molecule formed by joining two cysteine molecules together (a dipeptide), with each cysteine…

Collagen is the most common structural protein in vertebrates. Collagen provides the skin with flexibility and strength. Explain how the structure of a collagen fibre provides the…

What is present in all viruses, all prokaryotes and all eukaryotes? A ribose B deoxyribose C cytosine D thymine

The table shows some steps that can be made in carrying out the Benedict's test. The steps are: standardise volume of Benedict's solution and volume of test solution; boil with…

The diagrams show three examples of different bonds: bond 1 is shown between an N-H group and an O=C group (a dashed line); bond 2 is shown between a C(=O) group and an N-H group;…

Insulin is a globular protein involved in cell signalling. It is transported in the blood plasma from the cells that synthesise it to its target cells. A molecule of insulin…

Which statement correctly explains why blood plasma can be maintained at a stable temperature? A It has a low specific heat capacity. B It has a high specific heat capacity. C It…

Which polymers are present in all viruses and all prokaryotes? 1 polynucleotides; 2 polypeptides; 3 polysaccharides. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Which set of steps is the best method for conducting the emulsion test for lipids? A Add 2 cm3 of water to the sample. Pour the water into a test-tube containing 2 cm3 of ethanol.…

A student was provided with a solution of carbohydrate. They removed two samples and performed tests on each. Sample one was tested directly with Benedict's test, and the…

The Venn diagram shows three overlapping circles for sucrose, collagen and haemoglobin. Region C is the overlap of sucrose and collagen; region A is the overlap of sucrose and…

What describes cellulose? A a branched chain of 1-4 alpha-glucose B a branched chain of 1-4 beta-glucose C an unreactive linear chain of 1-4 alpha-glucose D an unreactive linear…

Which part of the structure of haemoglobin carries oxygen? A four polypeptide chains B haem groups C hydrogen bonds D hydrophilic R groups

What is the maximum number of hydrogen bonds that can form between two single water molecules? A 1 B 2 C 3 D 4

Which polymers are present in all viruses, all prokaryotes and all eukaryotes? 1 polynucleotides; 2 polypeptides; 3 polysaccharides. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2…

How many of the listed structures typically contain genetic material that has telomeres? The structures listed are: bacterial cell; chloroplast; mitochondrion; nucleus. A 1 B 2 C…

Steps 1, 2, 3 and 4 are used to test for a non-reducing sugar. 1 Put 5 cm3 of solution into a test-tube. 2 Add a few drops of acid. 3 Neutralise with alkali. 4 Add 6 cm3 of…

Which features contribute to the function of a cellulose molecule? 1 Long chains of glucose molecules coil into a helix. 2 Many hydrogen bonds form between adjacent chains. 3 It…

What correctly describes triglycerides? A non-polar molecules that are soluble in ethanol B non-polar molecules that are soluble in water C polar molecules that are soluble in…

Cocoa butter contains three different triglycerides made from the fatty acids oleic acid (O), palmitic acid (P) and stearic acid (S). The three triglycerides found in cocoa butter…

The Venn diagram shows three overlapping circles for unsaturated triglyceride, haemoglobin and collagen. Region C is the overlap of unsaturated triglyceride and haemoglobin;…

The diagram shows the amino acid glutamic acid, with the structure H-C bonded to a COOH group, an NH2 group, and a side chain CH2-CH2-COOH. What is the R group for glutamic acid?…

The diagram shows three interactions that hold protein molecules in shape. Interaction 1 is shown between an N-H group and an O=C group (a dashed line); interaction 2 is shown…

Glycogen and cellulose are polymers. Fig. 2.1 shows small, representative regions of a glycogen molecule and a cellulose molecule. The glycogen region is drawn as a branched chain…

Food crops such as barley and wheat contain gluten. Gluten contains two proteins, glutenin and gliadin. Table 4.1 contains descriptions of the structures of glutenin and gliadin.…

Polysaccharides, such as glycogen, are composed of thousands of monomers. Oligosaccharides are carbohydrates that contain three to ten monomers in their chain. Nystose is one…

Grapes are fruit that contain high concentrations of soluble sugars such as sucrose, fructose and glucose. The proportions of these sugars change as the grapes mature. You will…

When milk is dropped into a test-tube containing copper sulfate solution, the drop of milk sinks to the bottom of the test-tube. The speed at which the drop of milk sinks will…

Milk is a source of protein and reducing sugars. Different types of milk contain different concentrations of protein. The concentration of protein in milk can be measured using…

Until recently, the typical viruses known to science were 20-150 nm in size. In 2003, the Mimivirus was discovered with a size of approximately 680 nm. In 2013, the Pandoravirus…

What is present in all viruses? A uracil B ribose C thymine D guanine

The test for non-reducing sugars requires a second Benedict's test to be carried out. Which set of steps is the correct method for carrying out the non-reducing sugar test before…

Which molecules would be found in an oil (liquid) more than in a fat (solid)? Four triglyceride structures are shown. Molecule 1 has three saturated fatty acid chains (CH2)16-CH3.…

Which row about the bonding found in the primary, secondary, tertiary and quaternary structure of proteins is correct? primary secondary tertiary quaternary --- --- --- --- --- A…

Which bonds are present in all viruses? 1 phosphodiester 2 peptide 3 covalent A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

A student carried out the Benedict's test on four different concentrations of glucose solution and then recorded the time taken for the first appearance of a colour change (the…

Which statements about amylopectin and glycogen are correct? 1 Amylopectin and glycogen contain 1-4 glycosidic bonds. 2 Amylopectin contains beta-glucose. 3 Glycogen contains more…

How many statements about fatty acids are correct? - Fatty acids are either saturated or unsaturated. - Fatty acids always have at least two double bonds. - Long chains of fatty…

The diagram represents an amino acid: an H2N group, a central carbon bonded to an H and a variable side chain R, and a carboxyl COOH group. R represents a variable side chain.…

Which bonds are present in all viruses? 1 covalent 2 ester 3 phosphodiester A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

The diagram shows the structure of a monomer (alpha-glucose). Which molecules contain this monomer? The Venn diagram has three overlapping circles labelled amylopectin, glycogen…

A triglyceride consists of glycerol and three different fatty acids: linoleic acid (L), oleic acid (O) and palmitic acid (P). The diagram shows one possible arrangement of the…

Which statement about phospholipid molecules is correct? A They contain one saturated fatty acid and two unsaturated fatty acids. B They contain three phosphodiester bonds. C They…

Hydrogen bonding explains many of the properties of water, including the high latent heat of vaporisation and high specific heat capacity. For which processes in plants is…

Which feature of cellulose molecules contributes to the function of plant cell walls? A Adjacent cellulose molecules are linked by glycosidic bonds. B Branched chains of β-glucose…

Keratin is the structural protein in feathers of birds. Keratin polypeptides are composed of a high proportion of cysteine amino acids, which have sulfur-containing R groups.…