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.
Which molecules contain at least three double bonds? [Figure 12.1]
Which diagram correctly shows hydrogen bonding between two water molecules? [Figure 13.1]
Which statement describes an example of an extracellular enzyme?
Which row is correct for enzymes that catalyse reactions using the lock-and-key hypothesis?
A scientist investigated the rate of breakdown of hydrogen peroxide. Four experiments were carried out using different mixtures. • substrate only •...
What happens to the surface area to volume ratio of a cube when the length of each side is doubled?
Which events are part of the mitotic cell cycle? 1 interphase 2 telophase 3 cytokinesis
The estimated total number of red blood cells in the human body is 2.5 × 10¹³. It is estimated that, each day, 2.5 × 10¹¹ red blood cells are remov...
DNA polymerase catalyses condensation reactions between molecules during semi-conservative replication of DNA. What is joined by DNA polymerase?
Two polynucleotide strands make up a DNA molecule. Which description is correct?
The PDx1 protein is found in a wide range of animal species where it is regarded as essential for normal metabolism. In sand rats, the gene coding ...
Different tissues in a plant were supplied with a radioactively labelled substance to identify which tissues were actively synthesising mRNA. Which...
Which row correctly matches the structure and function of phloem sieve tube elements?
Which feature of xylem vessel elements helps adhesion during transpiration?
Mass flow is the bulk movement of materials from one place to another. How many of the vessels listed carry fluids by mass flow? • artery • phloem ...
Cellulose, lignin and suberin are components of various plant cell walls. Descriptions of these cell wall components are listed. 1 a component of t...
The arrows show the direction of water movement across a plant root, from water in the soil to the xylem. [Figure 29.1] Which arrows show water mov...
Which row correctly identifies sources and sinks of sugars?
The photomicrograph shows a section through a tissue with an artery. [Figure 31.1] Which row correctly shows the type of artery and whether the blo...
Heart surgery may cause a decrease in the transmission of impulses in the Purkyne tissue to the right side of the heart. What is a possible effect ...
The diagram shows a network of blood vessels that supply blood to muscle tissue in the human body. [Figure 33.1] What is a correct comparison betwe...
Scientists have shown that the oxygen dissociation curves for haemoglobin of smaller mammals are to the right of those of larger mammals. What does...
What is an effect of an increased concentration of carbon dioxide in the blood?
Two of the requirements of an efficient gas exchange system are a large surface area and a short diffusion distance. Which row correctly describes ...
What defines infectious diseases?
A hurricane destroys a large town on an island. People move away from the town and set up tents, where sanitation is poor. Which disease is most li...
Which statement correctly explains why viruses are unaffected by penicillin?
Which processes characterise the mode of action of phagocytes? 1 antibody production 2 receptor binding 3 endocytosis 4 exocytosis 5 hydrolysis
Table 1.1 lists cell structures that can be found in eukaryotic cells or prokaryotic cells. Some of these cell structures can be found in both type...
Cysteine is an amino acid containing sulfur. Fig. 2.1 shows the structure of the molecule formed by joining two cysteine molecules together. SH H-O...
Fig. 3.1 is a diagram of an area of phloem tissue from a transverse section through the stem of a squash plant, Cucurbita pepo. X Y companion cell ...
Tuberculosis (TB), influenza and polio are examples of infectious diseases.
Pneumonia is a severe lung disease that can interfere with gas exchange. A person with pneumonia can be connected to an ECMO machine. This machine ...
Collagen is the most common structural protein in vertebrates. Collagen provides the skin with flexibility and strength.
(a) You will investigate the effect of different temperatures on the permeability of the cell surface membrane of beetroot cells. Beetroot is a ve...
P1 is a slide of a stained transverse section through a plant root.
Fig. 1.1 is a drawing of a longitudinal section (LS) of a human kidney. [Figure 1.1]
Interferon-alpha (IFN-α) can be produced as a recombinant human protein to treat some types of cancer. The gene IFNA2 codes for IFN-α. One method o...
Salmon can be genetically modified (GM) to produce increased quantities of growth hormone, which is a protein. GM salmon modified in this way have ...
Array comparative genome hybridisation (aCGH) is a technique involving the use of a microarray to analyse a genome or sections of a genome.
Meiosis is described as a reduction division because the number of chromosomes in the daughter cells is reduced by half.
(a) Fig. 6.1 is a diagram of a section through a mitochondrion. [Figure 6.1]
(a) Fig. 7.1 is a diagram representing a synapse between a chemoreceptor cell from a human taste bud and a dendrite of a sensory neurone. [Figure 7.1]
Describe the functions of the internal membranes of the chloroplast in photosynthesis.
(a) Fig. 9.1 is a diagram of a relaxed sarcomere in striated muscle. [Figure 9.1]
The passage in Fig. 10.1 is about biodiversity. Complete the passage by using the most appropriate scientific terms. Biodiversity within an area ca...
Potatoes are underground organs made by the potato plant, Solanum tuberosum. Fig. 1.1 shows a potato plant. [Figure 1.1] Potatoes contain high quan...
Rice, Oryza sativa, is an important food crop. Rice plants are wind pollinated. Pollen containing the male gamete is transferred by the wind to fem...
A student used a light microscope to observe a blood smear on a microscope slide. An eyepiece graticule was used to measure the diameter of a white...
Which statement explains why it is necessary to use an electron microscope to see the cristae of a mitochondrion?