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.
When an organ is transplanted from one person to another, rejection of the non-self organ must be avoided. At the same time, the immune system of t...
Fig. 1.1 is a transmission electron micrograph of a cell from the root of thale cress, Arabidopsis thaliana. [Figure 1.1]
Sucrose is a disaccharide. Fig. 2.1 shows how sucrose is broken down in a reaction with hydrochloric acid. [Figure 2.1]
Researchers isolated a sucrase enzyme from the bacterium Bacillus subtilis. They immobilised the enzyme in alginate beads. The researchers investig...
Fig. 4.1 is a ribbon model of a molecule of haemoglobin. [Figure 4.1]
The toxins released by some pathogenic bacteria can be altered chemically so that they are harmless. These harmless toxins are called toxoids. Toxo...
Water absorbed by plant roots travels by different pathways from root hairs to the xylem. Fig. 6.1 shows these pathways in the root of Ranunculus a...
Fig. 1.1 is a drawing of a photomicrograph of a spongy mesophyll cell from a leaf. [Figure 1.1]
In 1953, James Watson and Francis Crick published details about the structure of DNA. They used experimental results from other scientists to help ...
Bacteria may be classified according to differences in cell wall structure. The differences are shown by using the Gram stain. • A Gram-positive ba...
Fig. 4.1 is a photomicrograph showing some cells in interphase and some cells in stages of mitosis. [Figure 4.1]
When tobacco smoke is inhaled, chemicals such as nicotine and carbon monoxide enter the circulatory system through the gas exchange system. Tar bui...
Enzyme inhibitors and monoclonal antibodies can be used in the treatment of disease.
Fig. 1.1 is a photomicrograph of root tip meristem. Different stages of the cell cycle are visible. Some cells are in the same stage of the cell cy...
Adipose tissue, which is composed of cells known as adipocytes, stores large quantities of triglycerides and functions as an energy storage tissue....
Nerium oleander is a xerophytic plant. A photomicrograph of a section through the leaf of N. oleander is shown in Fig. 3.1. [Figure 3.1]
Oxygen enters the blood stream from the alveoli in the lungs and carbon dioxide leaves the bloodstream to enter the alveoli. Most of the oxygen is ...
The fig tree, Ficus carica, and the papaya tree, Carica papaya, produce a milky-looking fluid known as latex. The latex is released when plant tiss...
(a) Fig. 6.1 is a list of infectious diseases. Each of the statements A to D describes a feature that applies to one or more of these diseases. [Fi...
Milk contains proteins which are used to make cheese. During cheese making, bacteria are added to the milk. The bacteria change the pH of the milk ...
J1 is a slide of a stained transverse section through a plant leaf. You are not expected to be familiar with this specimen. (a) The specimen on J1 ...
You are required to investigate the effect of concentration of hydrochloric acid (independent variable) on the rate of diffusion. The investigation...
M1 is a slide of a stained transverse section through a plant leaf. You are not expected to be familiar with this specimen. Use a sharp pencil for ...
Fruit growers need to know the concentration of sugars, such as sucrose, in the fruit so that it can be picked at the best time. As the fruit matur...
K1 is a slide of a stained transverse section through a plant stem. You are not expected to be familiar with this specimen.
The Sumatran orangutan, Pongo abelii, is found only on the island of Sumatra, Indonesia. Fig. 1.1 shows a Sumatran orangutan. [Figure 1.1] (a) The ...
Scientists have found very little evolutionary change in populations of two Australian songbirds, the zebra finch, Taeniopygia guttata castanotis, ...
3 (a) The lac operon is a section of DNA present in the genome of the bacterium Escherichia coli. The structural genes of the operon are only fully...
4 Domestic goats, Capra hircus, show a wide range of coat patterns and colours. One gene involved in coat colour and pattern has multiple alleles. ...
5 (a) Pigs are farm animals used for livestock in some parts of the world. The first genetically modified (transgenic) pigs were produced in 1985. ...
6 (a) Fig. 6.1 shows a transmission electron micrograph of a section through a mitochondrion. [Figure 6.1] Fig. 6.1 Table 6.1 sho...
7 (a) Fig. 7.1 outlines the process of non-cyclic photophosphorylation in the chloroplast of a leaf mesophyll cell. [Figure 7.1]
8 (a) In mammals, the nervous system and the endocrine system coordinate responses to the changes in internal and external environments.
The Sumatran tiger lives on the island of Sumatra, Indonesia. Fig. 1.1 shows a Sumatran tiger.
In the sweet pea plant, Lathyrus odoratus, one gene codes for flower colour and one gene codes for pollen grain shape. Flower colour is either purp...
Within a population, the variation for one characteristic is usually the result of genetic and environmental causes.
Adult Drosophila fruit flies feed on yeasts on the surface of ripe fruits. Female flies lay their eggs inside the fruit and the larvae feed inside ...
A severe reduction of blood flow to the brain causes cells to die. This is called a stroke. The after-effects of a stroke can range from recovery t...
Fig. 6.1 is an outline diagram showing two stages of aerobic respiration. [Fig. 6.1]
Fig. 7.1 shows part of a section through the leaf of a C4 plant such as maize. The letters A, B and C show three types of cell found in the leaf. [...
Describe how an action potential arriving at a presynaptic neurone can result in the release of acetylcholine into the synaptic cleft.
Outline the characteristic features of organisms in the domain Archaea.
Describe the process of selective reabsorption and explain how the cells of the proximal convoluted tubule are adapted to carry out selective reabs...
The Sulawesi macaque, Macaca nigra, is found on the large island of Sulawesi in Indonesia. The Sulawesi macaque is also found on other smaller isla...
In the fruit fly, Drosophila melanogaster, eye colour and wing shape are controlled by genes. • E/e are alleles of a gene involved in eye colour. ...
Meiosis is described as reduction division. Explain why meiosis is necessary in the life cycle of a sexually reproducing organism.
A study was carried out to investigate natural selection in the plant evening primrose, Oenothera biennis. Physiological changes associated with r...
People with Alzheimer's disease (AD) lose their ability to form new memories. One form of Alzheimer's disease, called familial Alzheimer's disease,...
Fig. 6.1 is a diagram of part of a mitochondrion showing some of the events occurring in oxidative phosphorylation. [Figure 6.1]
Fig. 7.1 is a transmission electron micrograph of part of a chloroplast of a leaf cell from maize. [Figure 7.1] Table 7.1 shows some substrates a...