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 table shows the results used to draw an oxygen dissociation curve for adult haemoglobin. partial pressure of oxygen /kPa: 1, 2, 3, 4, 5, 6, 7 ...
The graph shows the oxygen dissociation curves for adult haemoglobin at two carbon dioxide concentrations. [Graph showing two oxygen dissociation ...
Which substances can combine with adult haemoglobin and reduce the oxygen-carrying capacity of the blood? 1 carbon dioxide 2 carbon monoxide 3 hyd...
How many times must a molecule of carbon monoxide pass through a cell surface membrane as it diffuses from an air space in an alveolus, through a c...
The heart rate of a person at rest was recorded at intervals over two 15-minute periods. During the first five minutes of the second 15-minute per...
Emphysema is a type of chronic obstructive pulmonary disease (COPD). A person with emphysema has difficulties in breathing out. Why does emphysema...
Which factors contribute to outbreaks of measles after natural disasters? 1 contamination of drinking water with untreated sewage 2 lack of effect...
There are two main classes of antibiotics, broad spectrum and narrow spectrum. Broad spectrum antibiotics affect a wide range of bacteria, while n...
People with the autoimmune disease myasthenia gravis can have a treatment to relieve the symptoms. In this treatment, one of the components of thei...
Why are spleen cells fused with myeloma cells during monoclonal antibody production?
Fig. 1.1 is an image of a transverse section through the trachea of the gas exchange system. [Figure 1.1]
Starch molecules are the main storage molecules in many types of cereal grain, such as the grain of the barley plant.
T-helper lymphocytes and Leydig cells are two types of mammalian cells. The main role of T-helper lymphocytes and Leydig cells is to synthesise and...
Using a light microscope at a magnification of ×400, it is possible to identify different types of blood cell in prepared slides of mammalian blood.
Each meristem cell in a leaf bud is able to grow and divide by mitosis to produce two daughter cells that are genetically identical to each other a...
In March 2019, a tropical cyclone in the south-west Indian Ocean caused widespread flooding in a number of countries. The flooding and the damage c...
P1 is a slide of a stained transverse section through a plant stem.
The European eel, Anguilla anguilla, is a fish. The sizes of eel populations tend to remain relatively stable despite eels producing large numbers ...
The grey wolf, Canis lupus, is a large predator. During the 20th century, the grey wolf in south-west Europe was hunted almost to extinction.
Vitamin A deficiency is a widespread public health problem. One source of vitamin A is carotene in the diet. Carotene can be converted to vitamin A...
Red algae are multicellular photosynthetic protoctists that contain phycoerythrin. Phycoerythrin is a photosynthetic pigment.
Many processes and actions in plants and animals are due to the movement of ions. Table 5.1 lists several ions, the direction of movement of each i...
Dogs have an exceptionally good sense of smell. They can detect molecules in the air with a concentration of one part per trillion (10¹²).
Fig. 7.1 shows two chromosomes in one stage of meiosis. The letters G to M represent the dominant alleles of seven genes and the letters g to m rep...
Fig. 8.1 shows a transmission electron micrograph of a mitochondrion. [Figure 8.1]
Compare the characteristic features of the domains Eukarya and Bacteria.
Explain what is meant by bioinformatics and outline the role of bioinformatics following the sequencing of genomes of humans and parasites.
Students at a college often took a shortcut between the library and the tennis courts across an area of open land. The area of open land was covere...
Indigo carmine is a water-soluble indicator. When oxygen is bubbled through a solution of this indicator, the colour changes from colourless to blu...
Which cell organelles are clearly visible when viewed with a light microscope at high power (×400)? [Figure 1.1]
Microvilli and root hairs are characteristic structures of some cell types. Which row identifies some features of a microvillus and a root hair? [F...
The photomicrograph is of a plant cell. The cell is 25 µm in width from X to Y. What is the magnification of the photomicrograph? [Figure 3.1]
Which eukaryotic cell structures all contain nucleic acids?
Which statements about viruses are correct? 1 They contain DNA or RNA. 2 They use host cells to synthesise virus proteins. 3 They can have a protec...
What are features of prokaryote cells, chloroplasts and mitochondria? [Figure 6.1]
A student used Benedict's solution to test a sample known to contain carbohydrate. At the end of the test the solution was blue. Which carbohydrate...
Which row matches each molecule to a type of bond that is present? [Figure 9.1]
Which row shows features of a carbohydrate polymer found inside animal cells? [Figure 10.1]
The statements describe the structure of a polysaccharide found in the cell walls of certain plants. 1 The polysaccharide is composed of two differ...
The general formula for a saturated fatty acid is CnH2nO2. Which of these fatty acids are unsaturated? 1 C10H19COOH 2 C15H31COOH 3 C17H31COOH 4 C18...
What enables triglycerides to perform their functions in living organisms? 1 Triglycerides have hydrophobic and hydrophilic regions. 2 Triglyceride...
The diagrams show three examples of different bonds. Which bonds can hold the quaternary structure of proteins together? [Figure 14.1]
Which row correctly describes the primary structure, secondary structure, tertiary structure and quaternary structure of some proteins? [Figure 15.1]
Which relationships could be investigated using a colorimeter? 1 the effect of light intensity on the rate at which a solution of a light-sensitive...
Which transport mechanism does not require a concentration gradient to be present in order to take place?
High concentrations of ethanol disrupt cell membrane structure by denaturing proteins and increasing the separation of adjacent phospholipid molecu...
In an investigation, a plant cell was placed in pure water. The initial rate at which water molecules entered the cell, R, was greater than the ini...
The protein p53 is produced in a cell in response to DNA damage. This protein stops the cell cycle for a short time just before the DNA is replicat...
Some parts of a typical human chromosome are more numerous than others. Which parts are listed in order from the most numerous to the least numerous?
Which row correctly describes a stage of mitosis? [Figure 22.1]