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.
Yeast cells are unicellular eukaryotes that respond to the presence and absence of different sugars by switching genes on or off. One example of th...
Structures and compounds involved in the light dependent stage of photosynthesis are listed, A to J. A – thylakoid membrane B – starch grain C – c...
Fig. 7.1 shows part of the process of respiration in a mitochondrion. [Figure 7.1] With reference to Fig. 7.1, name: area A process B substance C
Sampling can be used to find the distribution and abundance of species in an area. Students sampled a rocky shore from a high tide area to a low ti...
Chlorella is a green, single-celled protoctist that is photosynthetic. Some students immobilised cells from a culture of this protoctist using the ...
The cotton bollworm, Helicoverpa armigera, is an insect pest of cotton. The adult cotton bollworm is a moth. The adult female moth lays eggs on cot...
Woodlice are small invertebrates that live in cool, damp places under wood and stones. Some students determined the respiration rate of woodlice at...
Cotton bollworms, Helicoverpa spp., are insect pests of cotton. Adult cotton bollworms are moths. The adult female moths lay eggs on cotton plants....
Some students decided to find the respiratory quotient (RQ) of germinating pea seeds. Pea seeds germinate best at temperatures between 13°C to 18°C...
The cotton bollworms, Helicoverpa armigera (old world bollworm) and Pectinophora gossypiella (pink bollworm), are insect pests of cotton. Adult cot...
Which row describes the membranes surrounding each cell structure?
The mean width of mitochondria in an electron micrograph is 6 mm. The magnification of the electron micrograph is ×9600. What is the actual mean wi...
Which sequence shows the correct order of some of the stages in the production and secretion of an enzyme?
Different antibiotics function in different ways. Ideally, the antibiotic kills the bacteria, but does not harm the infected human. One type of ant...
A prokaryotic cell is 5.0 µm in length. A virus particle is 300 nm in length. How many times larger is the prokaryotic cell compared to the virus p...
A student carries out a semi-quantitative test with Benedict’s solution. Which statement about this procedure is correct?
Which row is correct for carbohydrates?
Which shows the correct general formula for glycogen?
Chitin is a structural polysaccharide found in the hard, outer shells of animals such as crabs. Chitin is made of chains of amino sugars that conta...
Four fatty acids and their formulae are listed. caprylic acid CH₃(CH₂)₆COOH lauric acid CH₃(CH₂)₁₀COOH oleic acid CH₃(CH₂)₇CH=CH(CH₂)₇COOH palmitol...
Which molecule contains the smallest number of hydrogen atoms?
The diagram shows sucrose and sucralose. [Figure 12.1] The enzyme sucrase breaks down sucrose but cannot break down sucralose. Four students were a...
The graph shows the energy levels involved in an enzyme-catalysed reaction. Substrate molecules X and Y combine to give product Z. Which arrow show...
Which roles of the cell surface membrane result from the properties of the phospholipids? 1 to allow cytokinesis to occur in mitotic cell division ...
Which factors can be changed to affect the rate of facilitated diffusion across a cell surface membrane? 1 the surface area of the membrane 2 the c...
The diagram shows an experiment using a model cell to investigate the movement of substances. [Figure 16.1] Which statements are correct? 1 There i...
Human chromosomes have different parts. Some parts are more numerous than others. Which parts are listed in order from most numerous to least numer...
The diagram represents the cell cycle of a human cell. During the cell cycle the number of chromatids changes. [Figure 18.1] Which row is correct f...
A single skin cell was isolated and transferred to growth medium in a sterile Petri dish. The Petri dish was incubated for 16 days. During this tim...
A short piece of DNA, 18 base pairs long, was analysed to find the number of nucleotide bases in each of the polynucleotide strands. Some of the re...
The diagram shows a strand of DNA and mRNA during transcription. [Figure 21.1] Which row correctly identifies 1, 2 and 3?
Two students were discussing the involvement of DNA and RNA in transcription and translation. • Student 1 always stated correct facts. • Student 2 ...
Which descriptions of the adaptations of xylem vessel elements to their function are correct? 1 They have pits between vessels allowing water to pa...
The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause the diame...
A student wanted to find out the rate of transpiration using a potometer as shown. [Figure 25.1] The student was told to work out a value for trans...
In plants, assimilates such as sucrose are loaded from source cells into sieve tube elements. The assimilates are then transported from source to s...
The sinoatrial node initiates the cardiac cycle. What is the correct order in which the chambers of the heart contract?
The graph shows pressure changes in different parts of the heart during a mammalian cardiac cycle. W, X, Y and Z indicate when a valve opens or clo...
What is the main reaction occurring in blood capillaries at the gas exchange surface in a human lung?
Which reactions take place in blood that is passing through active tissues? 1 HbO₈ ⇌ Hb + 4O₂ 2 HbO₈ + H⁺ → HHb + 4O₂ 3 HCO₃⁻ + H⁺ → H₂CO₃ 4 H₂O + ...
Which row shows the tissues that are present in the wall of the trachea and in the wall of the bronchus? [Figure 32.1]
In some cases where a person has lung disease, the partial pressure of oxygen in the pulmonary veins is less than the partial pressure of oxygen in...
How many times must a molecule of carbon dioxide pass through a cell surface membrane as it diffuses from the plasma, through a cell in the capilla...
Which disease is spread by a vector?
Which statement explains why a one-dose vaccination programme for measles has not yet eliminated the disease?
What has contributed to the increase in antibiotic resistance in bacteria? 1 increased use of vaccines for animal diseases 2 mutations in bacterial...
Which statements correctly describe lymphocytes? 1 Each B-lymphocyte has the ability to make several types of antibody molecules. 2 Some B-lymphocy...
A country introduced a measles vaccination during a measles epidemic. Later, it was realised that vaccinated children were more likely to survive c...
Fig. 1.1 is a transmission electron micrograph of cells from duckweed, Spirodela oligorrhiza. [Figure 1.1]
Fig. 2.1 shows three molecules of water. [Figure 2.1] The human enzyme, salivary amylase, is composed of one polypeptide. Fig. 2.2 represents the s...