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 diagram shows a section of a strand of DNA. Which type of bond is labelled X?
Which row correctly describes cytosine?
During the production of protein molecules, only one strand from the DNA double helix is used. Which name is given to the DNA strand that is used t...
The diagram shows a longitudinal section of a phloem sieve tube with a companion cell. Where are the mitochondria located for the release of energy...
The diagram shows a phloem sieve tube element and a companion cell that are involved in translocation of sucrose. Which process correctly describes...
Which types of molecules are cotransported into companion cells?
The diagram shows a section through the human heart. Which label is correct?
The graph shows how the volume of the left ventricle changes during one cardiac cycle. Which point on the graph represents the start of atrial syst...
Which row is correct for an artery?
Which row shows the features of the gas exchange surface that increase diffusion of carbon dioxide and oxygen?
The electron micrograph shows some of the airways in the gaseous exchange system of an insect and the respiring body cells that surround them. Whic...
Which row is correct for the wall of the trachea and the wall of the bronchus?
A bacterial pathogen produces a protein that acts as a toxin. This toxin is harmful to humans. Scientists are developing monoclonal antibodies that...
Which statements are correct for penicillin? 1 It is harmful to prokaryotic cells. 2 It disrupts cell wall synthesis. 3 It becomes less effective w...
Which row is correct for the control or prevention methods for each disease?
Peptidoglycan is stained purple by the chemical crystal violet. Which cells would stain purple in the presence of crystal violet?
Animal cells, plant cells and prokaryotic cells have similarities and differences in their structure. Table 1.1 lists five organelles found in cel...
In the mammalian circulatory system, red blood cells travel through different types of blood vessel as they pass from the heart to respiring tissue...
Fig. 3.1 is a photomicrograph of a transverse section through a region of the wall of the bronchus in the gas exchange system. [Figure 3.1]
Fig. 4.1 shows the structure of sucrose, a disaccharide produced by plant cells. [Figure 4.1]
Trypsin is an enzyme which catalyses the hydrolysis of casein, a protein found in milk. Milk that contains casein has a cloudy, white appearance. ...
Fig. 6.1 shows a plant cell in a stage of mitosis. [Figure 6.1]
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 fru...
People who become infected with human immunodeficiency virus (HIV) are at risk of developing HIV/AIDs, particularly if antiretroviral therapy (ART)...
During transcription, base pairing occurs between nucleotides. Fig. 3.1 is a diagram to show complementary base pairing between a DNA nucleotide an...
Adult stem cells are undifferentiated cells that are found in most animal tissues. Adult stem cells can divide by mitosis throughout their lifespan...
Malaria is an infectious disease caused by the protoctist, Plasmodium. As part of its lifecycle, Plasmodium infects human red blood cells. Research...
The transport of water from the soil solution to the xylem of roots occurs by the apoplast and symplast pathways. Mineral ions can be transported d...
Fig. 1.1 shows the structure of the human gas exchange system. [Figure 1.1]
Stem cells are found throughout the human body. Lgr5+ stem cells are found in the lining of the small intestine. Fig. 2.1 is a flow chart showing s...
The five bases found in nucleic acids are described as nitrogenous organic compounds. There are two types of base. Fig. 3.1 shows the structure of ...
Biofuels contain alcohols that are produced by the fermentation of sugars derived from crop waste. This waste contains cellulose and other organic ...
T-lymphocytes are produced in bone marrow and mature in the thymus gland. When mature, T-lymphocytes leave the thymus gland to travel throughout th...
A student constructed a table to compare the structural features of a plant cell, a prokaryotic cell and a virus. Complete Table 6.1. [Table 6.1]
Milk is sometimes contaminated with substances such as starch. You will determine the concentration of starch in a sample of contaminated milk, usi...
J1 is a slide of a stained transverse section through a leaf.
Plant cells produce the enzyme catalase that catalyses the hydrolysis (breakdown) of hydrogen peroxide into water and oxygen, as shown in Fig. 1.1....
Different species of animal have neurones with different characteristics.
The leaves of many plants have stomata that show a regular daily rhythm of opening and closing over a period of 24 hours.
During aerobic respiration, cells respire substrates such as glucose to produce ATP. Some events that occur during aerobic respiration are: • The ...
The leaves of Mimosa pudica plants are made of a number of structures known as pinnae. The pinnae fold when the leaf is touched. This closes the le...
Lunularia cruciata is a primitive plant. Its body consists of a flattened sheet of photosynthetic tissue called a thallus. Fig. 5.1 shows L. crucia...
The mammalian kidney is responsible for: : the excretion of urea osmoregulation (the homeostatic control of the water potential of the blood).
Spea multiplicata is one of several species of American spadefoot toad. (a) Young spadefoot toads are called tadpoles and live in water in ponds. S...
Scientists use many different techniques in genetic engineering.
Lichens are found growing on trees, walls, rocks and soil. Fig. 9.1 shows a lichen of the genus Usnea. Usnea can tolerate only low concentrations o...
Populations of the moth Biston betularia live in Europe and in North America. The most common phenotype on both continents is a pale wing colour wi...
1 (a) Fig. 1.1 is a diagram of part of a Bowman's capsule and a glomerular capillary. [Figure 1.1]
2 Several different processes can affect allele frequencies in populations.
3 The treatment of many diseases has been improved by the use of genetic technology in medicine.