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.
The photomicrographs show cells in various stages of the cell cycle. [Figure 16.1] Which cells contain twice as many DNA molecules as a cell from t...
A group of chemicals used to treat cancer prevents the formation of the spindle during mitosis. Which phase of mitosis is the first to be affected?
Mitosis is an important process for organisms. Which features of mitosis are important for single-celled organisms? 1 asexual reproduction 2 growth...
Which statements about complementary base pairing are correct? 1 Cytosine forms three hydrogen bonds with guanine. 2 Purines and pyrimidines are di...
Bacteria were grown in a medium containing 15N. After several generations, all of the DNA contained 15N. Some of these bacteria were transferred to...
Which statements about tRNA are correct? 1 It contains base pairing. 2 It contains hydrogen bonds. 3 It contains uracil. 4 It is single stranded.
The diagram shows the nucleotide sequence of a small section of a gene which is transcribed. TTCTTCCCGTTC The table shows the amino acids coded for...
The graph shows the diameter of a tree trunk at different times. [Figure 23.1] Which statement is correct?
Some plant species can take up toxic heavy metal ions that are dissolved in water in the soil. These ions accumulate in the aerial parts of the pla...
The diagram shows the results of an experiment on transpiration using two different leaves. Each leaf was left on a balance in daylight in a closed...
Which statement about the transport of sucrose is correct?
Which of the tissue types below are present in the walls of all blood vessels? 1 collagen 2 elastic 3 endothelial 4 smooth muscle
Which components of blood are present in tissue fluid?
The graph shows changes in percentage saturation of haemoglobin with oxygen in the blood of a human and of another animal. The partial pressure of ...
Which statements about the formation of haemoglobinic acid are correct? 1 It can only occur with the dissociation of oxygen from haemoglobin. 2 It ...
The photograph shows a type of blood cell. [Figure 31.1] Which statements about these cells are correct? 1 Oxygen diffuses through the phospholipid...
A student was asked to describe the differences between four microscope slides of sections taken from different parts of the gas exchange system. s...
Which components of the human gas exchange system help to reduce the effects of carcinogens in tar?
What is correct about the affinity between haemoglobin and the gases carbon dioxide, carbon monoxide and oxygen?
The table shows the names of five pathogens. [Figure 35.1] Which row matches the pathogens with the diseases they cause?
Which disease exhibits all the following features? • It can be transmitted by animals to other animals, including humans. • One mode of transmissio...
The proportion of the local population who have malaria in area R is higher than the proportion in area S. Which factor causes this difference?
Which statement describes how passive natural immunity is obtained?
What describes a non-specific immune response?
What explains why monoclonal antibodies can be used to target cancer cells?
Which organelles are enclosed in a single phospholipid bilayer and contain hydrolytic enzymes?
The DNA of prokaryotes is naked and circular. Which statement describes how the DNA of eukaryotes differs from that of prokaryotes?
The recently discovered Pandoravirus measures 1000 nm in diameter. The Mimivirus has a diameter of 400 nm. What can be detected using a light micro...
What are found in chloroplasts and mitochondria? 1 DNA 2 70S ribosomes 3 mRNA
Boiling the bones and teeth from dead animals can be used to produce a type of glue. The glue is formed from the collagen fibres present in bones a...
What describes the primary structure of a protein?
The diagrams show four monosaccharides with the formula C6H12O6. Which diagram shows α-glucose? [Diagrams of four monosaccharides labeled A, B, C, D]
Complete digestion of polysaccharides requires all the glycosidic bonds between the monomers to be broken. Amylase only breaks α-1,4 glycosidic bon...
The diagram shows the results of tests on four solutions containing biological molecules. Which shows the solution that contains only starch and pr...
The enzyme invertase catalyses the breakdown of sucrose to glucose and fructose. Three different enzyme inhibitors of invertase X, Y and Z were inv...
The following statements are about enzymes. 1 Folding of an enzyme molecule causes the formation of the active site. 2 The shape of the active site...
How is the Michaelis-Menten constant (Km) used?
Proteins in the cell surface membranes of human cells and mouse cells were labelled with fluorescent dyes. The human cells were labelled with a red...
The diagram shows a plant cell. [Diagram of a plant cell] The plant cell is put into a solution with a water potential less negative than the cell ...
The diagram shows the fluid mosaic model of membrane structure. [Diagram of fluid mosaic model with components labeled 1, 2, 3, 4] Which molecules ...
The photomicrograph shows a stage of mitosis. [Photomicrograph of a cell in metaphase] What would be correct for the next stage in mitosis? [Table ...
The diagram shows part of the organisation of a DNA molecule and the associated histones. [Diagram of DNA packaging with labels P, Q, R] Which stat...
The bacterium Escherichia coli divides once every 50 minutes at 36 °C. E. coli were grown on a medium containing only heavy nitrogen, 15N, until al...
Electron micrographs may show large numbers of ribosomes forming chains along mRNA molecules. What is the advantage of this arrangement, compared t...
Which row is correct for adenine? [Table with columns 'has a single ring structure', 'is a purine', 'joins to its complementary base with 3 hydroge...
The graph shows the loss of mass in a potted plant due to transpiration. [Graph showing mass/g vs. time/minutes with a point X] What could have occ...
Which row is correct for a phloem sieve tube element? [Table with columns 'cell surface membrane', 'cytoplasm', 'nucleus', '80S ribosomes' and rows...
An aphid, such as a greenfly, uses a tubular mouthpart called a stylet to feed on nutrients in the plant. It inserts the stylet through the surface...
Which statement correctly describes transport pathways in dicotyledonous plants?
The graph shows pressure changes during a cardiac cycle. [Graph showing pressure/kPa vs. time/s with curves labeled W, X, Y, Z] Which row correctly...