Cambridge & Pearson Edexcel Past Paper Questions
Browse 35,704 questions from Cambridge O-Level & A-Level and Pearson Edexcel IGCSE & IAL exams. Click any question to practice.
Many factors affect the rate of cellular respiration.
Sweet peas are garden plants that vary in height. • Tall sweet peas grow to 200 cm in height. • Dwarf sweet peas grow to 30 cm in height. • Tall sw...
(a) Glycolysis is a biochemical pathway that occurs in the cytoplasm of cells. In glycolysis, a molecule of glucose is metabolised to two molecule...
(a) In sexual reproduction, meiosis occurs to produce haploid gametes from a diploid cell.
(a) The sea blush, Plectritis congesta, is a flowering plant that grows on the west coast of North America. Individual sea blush plants produce fr...
Genetic technology uses many different enzymes and techniques. (a) Restriction endonucleases are used in genetic modification. These enzymes occur...
(a) Warfarin is a poison used to kill rats. Some rats are resistant to warfarin and can survive the effects of the poison. Warfarin resistance is d...
(a) Fig. 6.1 is a photomicrograph of a section through a Bowman's capsule and a glomerulus. [Figure 6.1]
(a) A striated muscle cell (muscle fibre) will contract when stimulated by a motor neurone at a neuromuscular junction. Air temperature can affect...
(a) In plants such as rice, Oryza sativa, rubisco has a low rate of activity, which in turn affects the rate of photosynthesis. The cereal crop sor...
(a) The passage outlines the endocrine system. Complete the passage by using the most appropriate scientific terms. The endocrine system consists...
(a) Many zoos around the world are involved in captive breeding programmes for endangered species.
The Krebs cycle was named after the biochemist Sir Hans Krebs, who worked out the sequence in 1937. Fig. 1.1 is an outline of the Krebs cycle. acet...
Humans use antibiotics to treat bacterial infections. The increased use of antibiotics has led to an increase in the number of strains of bacteria ...
Gene expression in a cell is controlled. When a gene is expressed (switched on), the gene is transcribed. When a gene is not expressed (switched of...
One cause of the genetic disease severe combined immunodeficiency (SCID) is a mutation in the ADA gene. This mutation results in a deficiency of th...
A freshwater fish species, Oryzias latipes, has individuals with four body colour patterns, as shown in Table 5.1. phenotype red white red with bla...
(a) Fig. 6.1 shows part of the Bowman's capsule of a kidney nephron. lumen of capillary lumen of Bowman's capsule Name structures A, B and C. A B C...
(a) Sarcomeres are the functioning units of the myofibrils of the muscle fibres (muscle cells) of striated muscle. The arrival of an action potenti...
(a) Fig. 8.1 is a diagram of a chloroplast. K L M Fig. 8.1 Using the letters K–N, complete Table 8.1. Each letter may be used once, more than once,...
(a) Dopamine is a neurotransmitter released in some synapses in the brain. The release and action of dopamine is similar to that of acetylcholine. ...
(a) The moose, Alces alces, is a large member of the deer family. It lives in temperate forests in North America and northern Europe, where snow is...
Catalase is an enzyme that is found in many plant cells and animal cells. Catalase breaks down hydrogen peroxide, which is a waste product from cel...
Sea trout, Salmo trutta, are found in rivers and coastal seawaters in many regions of the world. Sea trout lay their eggs in rivers and the young f...
Polyphenol oxidase is an enzyme involved in the browning of fruit. Fig. 1.1 shows browning of the skin of bananas. [Figure 1.1] A student extracted...
Air pollution due to motor vehicles is an environmental issue that needs constant monitoring. Lichens consist of protoctists and fungi living in cl...
Hydrogencarbonate indicator is a water-soluble solution that can act as a source of carbon dioxide for aquatic photosynthetic organisms. The soluti...
Lichens consist of protoctists and fungi living in close association. Both types of organism benefit from this association. Lichens are found in a ...
A prokaryotic cell which is 1 µm in diameter is magnified 50000 times in an electron micrograph. What is the diameter of the cell in the electron m...
The diagram shows a plant cell with some labelled structures. [Diagram] Which labelled structures are bound by a double membrane?
Which size of ribosome is found in mitochondria and typical prokaryotic cells?
Which row about typical prokaryotic cells and typical animal cells is correct? [Table with columns 'lysosomes present for the break down of old org...
Which row is correct for the structures present in typical plant cells and typical animal cells? [Table with columns 'cell structure', 'plant cell'...
Which row is correct for cellulose? [Table with columns 'rotation of alternate monomers by 180°', 'shape of molecule', 'hydrogen bonds between mole...
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 nex...
The diagram shows naturally occurring D-glucose and a form of glucose that can be synthesised in the laboratory, known as L-glucose. [Diagram of D-...
Tests for biological molecules were carried out on three solutions. Each solution contained only one type of biological molecule. The observations ...
Which row describes the expected effect on Vmax and Km when a competitive reversible inhibitor is added to an enzyme-catalysed reaction? [Table wit...
The graph shows the effect of substrate concentration on the rates of reaction of three enzymes, X, Y, and Z. [Graph showing rate of reaction vs su...
Which row correctly identifies the weak and strong bonds in the tertiary and quaternary structure of a typical protein? [Table with columns 'disulf...
Which row correctly describes haemoglobin? [Table with four columns describing aspects of haemoglobin]
Which process always takes place without the involvement of energy from ATP?
The diagram shows the entry of molecule X into a cell. [Diagram of molecule X entering a cell] Which row shows a property of molecule X and the eff...
The electron micrograph shows some human blood cells. [Electron micrograph of human blood cells with one cell labelled X] Which row correctly shows...
A red indicator solution was mixed with agar and the resulting solid was cut into small cylindrical blocks. The blocks were placed in an acid which...
Which metabolic processes will be very active in a cell that has just completed cytokinesis? 1 ATP formation 2 DNA replication 3 protein synthesis
The diagram shows a typical mitotic cell cycle and the point in the cell cycle that has been reached by each of four cells, V, W, X and Y. [Diagram...
The graph shows the mean length of the spindle fibres during mitosis. [Graph showing mean length of spindle fibres over time, with regions A, B, C,...
The mRNA codons ACU, ACC, ACA and ACG all code for the same amino acid, threonine. Which anticodons could specify an amino acid other than threonin...
Which bond formation does DNA polymerase catalyse?