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 photomicrograph shows the wall of a bronchus as seen with a light microscope. [Photomicrograph of the wall of a bronchus with labels X, Y, Z] W...
Which factors affect the global pattern of distribution of malaria? 1 the disease is mainly restricted to tropical and subtropical environments 2 t...
Which molecule could be a self antigen?
The diagram shows an antibody molecule with some parts labelled. [Diagram of an antibody molecule with parts P, W, V, U, R, S, T labelled] Which ro...
Fig. 1.1 shows a diagram of the fluid mosaic model of the structure of the cell surface membrane.
Haemoglobin is a globular protein containing haem groups. Explain how the presence of haem groups allows the haemoglobin molecule to transport oxygen.
The lock-and-key hypothesis and the induced-fit hypothesis are used to describe the interaction of enzymes and their substrates. Describe one simil...
Fig. 4.1 is a photomicrograph of a copepod. These animals are found living in sea water and in fresh water environments.
Fig. 5.1 is a photomicrograph of a longitudinal section through part of the stem of a plant.
Alveolar macrophages are phagocytes found in the human gas exchange system. They produce hydrolytic enzymes, such as lysozyme, to digest pathogens ...
The wall of the small intestine is highly folded to form villi. Between the villi are infoldings known as crypts of Lieberkühn. Fig. 1.1 is a diagr...
Cholera is an infectious intestinal disease caused by a bacterial pathogen.
The gene LCT codes for the enzyme lactase. In babies, lactase synthesis is necessary for digesting lactose, the sugar found in milk. Another gene, ...
Bacteria can be classified according to the type of cell wall they have. Gram-negative bacteria have a cell wall with an outer layer known as the o...
A plant that is described as a mesophyte has evolved to grow in conditions that do not normally experience water stress (low availability of water)...
In the pulmonary circulation of a mammal, deoxygenated blood becomes oxygenated when red blood cells pass through alveolar capillaries and haemoglo...
Many substances can move through cell surface membranes between the cytoplasm of animal cells and the extracellular environment. (a) A student made...
Collagen is a fibrous protein found in many tissues in animals. Fig. 2.1 shows the composition of a collagen fibre.
(a) Describe the induced-fit hypothesis of enzyme action. (b) Many marine organisms can become attached to hard surfaces such as rocks or the surfa...
(a) Fig. 4.1 shows a phosphorylated nucleotide which is one of the monomers that is used to synthesise DNA during replication. (b) Fig. 4.2 shows a...
Inhibitors are substances that prevent biological processes in a variety of different ways. Table 5.1 shows some antibiotics, their modes of action...
(a) A student studied the structure of a mammalian heart. The student took a photograph of the left side of a dissected heart as shown in Fig. 6.1....
The bacterium Streptococcus pneumoniae is commonly found in the throat. S. pneumoniae produces hydrogen peroxide as it grows. A sample can be taken...
Dialysis tubing is a partially permeable membrane. Glucose molecules can diffuse through the dialysis tubing. You are required to investigate the d...
K1 is a slide of a stained transverse section through a root.
Guinea pigs, Cavia porcellus, vary in the length and colour of their fur. Fig. 1.1 shows a guinea pig with short black fur. [Figure 1.1] Two genes ...
Exserohilum turcicum is a fungal pathogen. The growth of the mycelium of the fungus damages the leaves of maize plants, Zea mays. Leaf damage reduc...
Plants have several different photosynthetic pigments in their chloroplasts. (a) A student separated and identified the chloroplast pigments presen...
The wolf, Canis lupus, lives in North America. Wolves may have a grey or a black coat colour. The colour of an individual wolf depends on the DNA i...
The endocrine system and the nervous system both coordinate responses in mammals. (a) Complete Table 5.1 to show the features of three cell-signall...
The distribution of the large blue butterfly, Phengaris arion, extends across Europe and Asia. It is assessed by the International Union for Conser...
In aerobic respiration, most ATP is produced by oxidative phosphorylation. (a) Outline the features of ATP that make it suitable as the universal e...
LibertyLink® soybean is a genetically modified crop. It was first grown in 1996 and used in food products from 1998. It has been grown in 6 countri...
(a) Fig. 9.1 shows a longitudinal section of a human kidney. [Figure 9.1] Name the regions of the kidney labelled X and Y in Fig. 9.1. X Y (b) A bi...
Explain the relationship between genes, proteins and phenotype, with reference to two examples of genetic diseases in humans.
Rice, Oryza sativa, is a crop plant that has adapted to grow in flooded fields. Fig. 1.1 outlines the effects on rice plants of growing in flooded ...
Explain the terms gene, genotype and phenotype. gene genotype phenotype
The lac operon is present in the genome of the bacterium Escherichia coli. When glucose is not available, the presence of lactose in the extracellu...
The evolution of antibiotic resistance in bacteria has occurred as a result of natural selection.
Metachromatic leukodystrophy (MLD) is a genetic disease that affects the nervous system. MLD is caused by mutations in the ARSA gene located on chr...
Phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB) are enzymes involved in the regulation of blood glucose concentration. Fig. 6.1 shows a...
The Venus fly trap, Dionaea muscipula, is a plant that can capture insects. Each leaf of a Venus fly trap is modified to form 2 lobes. Fig. 7.1 sho...
Palm oil is the most widely used vegetable oil. It is obtained from the African oil palm, Elaeis guineensis. Oil palms are the highest yielding veg...
Fig. 9.1 shows an absorption spectrum for chlorophyll a and the corresponding action spectrum for a species of plant. Explain what is meant by an a...
Nerve impulses can be transmitted along a myelinated motor neurone to a neuromuscular junction at fast speeds of up to 100ms⁻¹. Outline how a trans...
The endocrine system and the nervous system both coordinate responses in mammals.
In aerobic respiration, most ATP is produced by oxidative phosphorylation.
Fig. 9.1 shows a longitudinal section of a human kidney.
Juglone is a chemical produced by plants in the genus Juglans, which includes different species of walnut tree. Fig. 1.1 shows a black walnut tree....
Compounds containing nitrite ions (NO₂⁻) are present in many foods eaten by humans. Scientists tested the effect of different concentrations of nit...