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 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...
When they remain at high altitudes the red blood cell count of humans increases. Why does this occur? 1 to increase the Bohr effect 2 to increase t...
Which comparisons of blood, tissue fluid and lymph are correct? 1 Blood has a higher concentration of proteins than tissue fluid because the larger...
The photomicrograph shows a section through lung tissue. [Photomicrograph of lung tissue] Which structures are present in this photomicrograph? [Ta...
An athlete who smokes just before a race may not be able to run at their maximum speed because less oxygen is carried by the blood. Which explanati...
Some of the requirements of an efficient gas exchange system are a large surface area and a short diffusion distance. What is correct about how alv...
The diagram shows three types of cell found in the human gas exchange system. [Diagrams of three cell types labeled X, Y, Z] Apart from causing can...
Some common antibiotics are listed. The action of each antibiotic is described. 1 rifampicin – inhibits RNA polymerase 2 streptomycin – inhibits 70...
What could cause an outbreak of malaria in a country after it had been eliminated? 1 mosquitoes become resistant to insecticides 2 migration of pop...
Which disease is caused by a bacterium and can be spread by airborne droplets?
Smallpox has been eradicated, but malaria and cholera have not. Which statements correctly explain this? 1 Cholera pathogens in the intestines are ...
When a person is given a vaccination immunity to certain pathogens develops. Which of the effects of vaccination are correct? 1 production of antib...
What is the first response by the immune system to a pathogen?
Answer all the questions. (a) Each of the statements A to D describes a structure found in eukaryotic cells. Identify the structure that is describ...
Phosphatases are enzymes that catalyse the removal of phosphate groups from organic compounds. Some students investigated the effect of substrate c...
Fig. 3.1 is a diagram that shows the structure of an antibody molecule. [Figure 3.1]
(a) Fig. 4.1 shows part of a DNA molecule. [Figure 4.1] Use Fig. 4.1 to explain how the structure of mRNA differs from the structure of DNA. (b) Fi...
Sugar molecules enter cells through transport proteins. (a) Explain why transport proteins are required for the movement of sugar molecules, such a...
Cholera bacteria release the toxin, choleragen, when they are in the intestine. (a) (i) Name the bacterium that is the pathogen of cholera. (ii) De...
In multicellular organisms, the structure of different cell types is adapted to their function. Within these cells there are a number of different ...
Lipase is an enzyme with many commercial uses. Some species of bacteria are of great interest as they produce large quantities of lipase.
Malaria is a disease caused by the protoctist, Plasmodium. The organism has a very complex life cycle as it has two hosts, a human and a mosquito. ...
Meristematic tissue is found in the growing regions of plants, such as root tips.
Some pathogens can enter the human body through the gas exchange system.
As a result of transcription and translation, a polypeptide chain is produced. Proteins with quaternary structure contain two or more polypeptide c...
Mammals have a closed double circulation system.
Fig. 2.1 is a transmission electron micrograph of a cell from a leaf. [Figure 2.1]
Name the causative organism of tuberculosis (TB).
Complete Table 4.1 by using a tick (✔) to indicate which statements apply to each of the molecules. Use a cross (x) for statements that do not appl...
Describe the process of DNA replication.
In the space below, draw a diagram to show a hydrogen bond between two water molecules.
J1 is a slide of a stained transverse section through a plant stem. You are not expected to be familiar with this specimen.
M1 is a slide of a stained transverse section through a plant stem. You are not expected to be familiar with this specimen.
When a person eats food containing starch, the enzyme amylase is released to hydrolyse (break down) the starch into reducing sugar. As the food pas...
K1 is a slide of a stained transverse section through a plant root. You are not expected to be familiar with this specimen. You are required to: • ...