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.
Fig. 6.1 shows photomicrographs of individual cells from the root tip of an onion, Allium sp., at different times in the mitotic cell cycle. [Figur...
Different types of respiratory substrate can have different energy values and therefore release different quantities of energy when they are respir...
The orca, Orcinus orca, has the largest distribution of all aquatic mammals and is found in nearly all seas and oceans. Orca are social mammals tha...
Gentamicin is an antibiotic used to treat severe bacterial infections in children. (a) Some children have a genetic mutation in the gene MT-RNR1. I...
The HFE gene codes for the HFE protein, which has a role in the regulation of iron absorption by the body. Iron is an essential mineral that can be...
[Figure 5.1] shows a photomicrograph of a single plant cell in a stage of meiosis. Describe the stage of meiosis shown in Fig. 5.1.
[Figure 6.1] outlines part of the control mechanism that regulates blood glucose concentration.
The Sumatran tiger, Panthera tigris sumatrae, is classified as critically endangered on the International Union for Conservation of Nature (IUCN) R...
(a) In the link reaction, a two-carbon acetyl group is produced from pyruvate. The acetyl group is transferred to coenzyme A to form acetyl coenzym...
The chloroplasts of leaves of tobacco plants, Nicotiana sp., contain chlorophyll a and chlorophyll b. (a) Describe the role of chlorophyll b in pho...
(a) Fig. 10.1 shows chemoreceptor cells in a taste bud. Two of the chemoreceptor cells have formed synapses with sensory neurone dendrites. [Figure...
Sand dunes are important ecosystems that are found in many regions of the world. Sand dune ecosystems can be damaged by natural events, such as ext...
Nagarahole National Park in southern India is a forest ecosystem that is important for the conservation of large mammals such as the Asian elephant...
Type 1 diabetes is a disease that occurs when the pancreas stops producing insulin. Type 1 diabetes occurs most commonly in children and is often t...
The diagram shows a section through a type of epithelium. [Figure 1.1] Where is this type of epithelium found in the respiratory system?
Which statement is an example of epidemiological evidence linking smoking to lung cancer?
Which feature of haemoglobin makes it a globular protein?
Which processes allow movement into and out of a cell? 1 active transport 2 diffusion 3 facilitated diffusion 4 osmosis
Some plant and animal cells were placed in different solutions and the results are shown. [Figure 5.1] Which cells were placed in which solution?
The diagrams represent the cross section of the stem, root and leaf of a non-woody dicotyledonous plant. In each section the distribution of the ti...
What occurs in the sieve tube elements of a photosynthesising leaf and an actively growing root?
Some soil-borne fungi cause wilting in crop plants by growing within the xylem vessels. Which process will be directly affected by these fungi?
The diagram shows part of the nitrogen cycle. [Figure 9.1] Which sequence of numbers correctly shows the roles of different types of microorganism ...
Two species of animal are found in the same area of forest and grassland. In the spring and summer they eat the same plant food. However, in the au...
The diagram shows a tropical ocean food chain with 10% efficiency of energy transfer between trophic levels. phytoplankton → herbivorous zooplankto...
The diagram below is drawn from an electron micrograph of an animal cell. [Figure 12.1] Which represents the same cell, seen under a light (optical...
The diagram shows a stage micrometer, with divisions 0.1 mm apart, viewed through an eyepiece containing a graticule. [Figure 13.1] What is the are...
Which observations suggest that a cell is eukaryotic?
Which structures are found in both animal and plant cells? 1 centriole 2 lysosome 3 nucleolus 4 vacuole
Which structures are measured using these units?
When making measurements in experiments, which methods have parallax errors? 1 using a calibrated eyepiece graticule to measure length 2 using a me...
Membranes within and at the surface of cells have different roles. The diagram allows the identification of the various organelles within the cell,...
The diagram shows chromosomes at metaphase of mitosis. [Figure 19.1] What are the diploid and haploid numbers for this species?
DNA is said to replicate in a semi-conservative way. Results of Meselson and Stahl's experiments gave overwhelming support to this theory. They use...
What occurs in anaphase of mitosis?
In a DNA molecule, the base sequence AGT codes for the amino acid serine. What is the base sequence of the anti-codon on the tRNA to which serine b...
What is the minimum number of base substitutions required to change the nucleotide sequence of the HbA (normal) allele to the HbS (sickle cell) all...
An enzyme is completely denatured at 50 °C. A fixed concentration of this enzyme is added to a fixed concentration of its substrate. The time taken...
The enzyme lysozyme secreted from tear glands forms deposits on contact lenses. Which ingredient would be effective in a contact lens cleaner for r...
A student tested four samples of food, A, B, C and D, for the presence of • lipids • protein • reducing sugars • starch One of the food samples, mi...
Which diagram represents part of the ring form of a molecule of β-glucose?
Which statement describes how the molecular structure of starch is suited to its function?
Which feature distinguishes starch from glycogen?
How many fatty acid residues are normally present in a phospholipid molecule?
As a frozen lake warms after a cold winter, mineral nutrients are brought to the surface. Which properties of water contribute to this process? 1 I...
What would be the result of analysing part of a DNA molecule?
What are the causative agents of cholera, malaria and TB?
What is a difference between T-lymphocytes and B-lymphocytes in the immune system?
In an investigation into the immune response, a volunteer was exposed to two different antigens, X and Y. The relative antibody concentration in th...
40% of the world's population live in an area where malaria is a threat to health. In recent years there have been many more cases in Africa. What ...