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.
4 Genetic crosses can be used to investigate patterns of inheritance.
5 Phenotypic variation exists in natural populations. There are many causes of variation. Natural selection determines which phenotypes are advanta...
6 (a) DCPIP is an indicator and can be used to determine the rate of respiration of organisms such as yeast. [Figure 6.1]
7 (a) Paper chromatography is a technique that can be used to separate and identify different chloroplast pigments.
8 (a) Fig. 8.1 is a diagram of a motor neurone. [Figure 8.1]
9 The red ruffed lemur, Varecia rubra, is a mammal found only in the rainforests of the Masoala region in north east Madagascar. Fig. 9.1 shows a r...
10 (a) Blood glucose concentration is maintained around a set point by homeostasis.
Different species of animal have neurones with different characteristics. (a) Fig. 1.1 is a diagram of a motor neurone of a rat and a motor neurone...
The mammalian kidney is responsible for: • the excretion of urea • osmoregulation (the homeostatic control of the water potential of the blood).
Scientists use many different techniques in genetic engineering. (a) Sometimes the gene for genetic engineering cannot be extracted from the donor ...
Algae are a diverse group of photosynthetic eukaryotes in the kingdom Protoctista. Rhodomonas salina and Skeletonema costatum are two species of al...
A group of ecologists investigated the biodiversity of two peat bog ecosystems, A and B. Peat bogs are wetland ecosystems that often contain rare s...
In the light-dependent stage of photosynthesis, electrons and hydrogen ions are accepted by the coenzyme NADP, which becomes reduced. DCPIP is a dy...
The two-spot ladybird, Adalia bipunctata, is a species of small, flying beetle that is found in northern Europe and other parts of the world. The w...
A student observed some cells using a microscope with an eyepiece graticule. [Figure showing cells and eyepiece graticule scale] They then replaced...
Which structures will be present in a cell that causes cholera? 1 circular DNA 2 cytoplasmic DNA 3 70S ribosomes
Which organelles have a partially permeable membrane? 1 Golgi apparatus 2 lysosome 3 mitochondrion 4 ribosome
Mouse cells were grown in a dish containing a growth medium. Radioactively labelled amino acids were added to the growth medium. The table shows th...
The electron micrograph shows a section through a cell. [Electron micrograph of a cell] What would be present in this type of cell?
A student carried out four tests for biological molecules. The observations are shown in the table. [Table with columns 'test' and 'observations' a...
The diagram shows some relationships between features of carbohydrates. [Venn diagram showing α-glucose, 1,4 bonds, highly branched and regions 1, ...
The diagram shows a triglyceride molecule. [Diagram of a triglyceride molecule] Which statement is correct for the structure and function of this t...
Enzyme P has been found in a tropical grass. • The enzyme catalyses the hydrolysis of the fungal polysaccharide, chitin, into amino sugars. • It al...
Which bonds between amino acids hold the shape of the secondary structure and also the tertiary structure of proteins?
Resilin is a protein found in the wings of insects. It is an elastic, fibrous protein and scientists have suggested that it may have an important r...
Collagen is a protein that helps to strengthen and increase the elasticity and hydration of the skin. Aging can lead to dry skin and the formation ...
What is the effect of an enzyme in an enzyme-catalysed reaction?
How is the Michaelis–Menten constant (Kₘ) used?
Some students investigated the effect of pH on the rate of starch digestion by amylase at 20 °C. • They added 2 cm³ of a 1% amylase solution and 1 ...
Which statements are correct for a non-competitive inhibitor of enzyme action? 1 Increasing the concentration of the enzyme's substrate will reduce...
What can increase the fluidity of the cell surface membrane at low temperatures? 1 double bonds between carbon atoms in the fatty acid chains 2 cho...
Which statements about the proteins and glycoproteins in cell surface membranes are correct? 1 They can allow cells to bond together to form tissue...
In an experiment, four different-sized cubes of colourless agar were placed into a blue dye. The time taken for each cube to turn blue was recorded...
The stalk of a dandelion flower is a hollow tube called a scape. Pieces of the scape are cut as shown by the dotted lines and placed in sucrose sol...
Telomeres prevent the loss of genes during DNA replication. Which row correctly shows cell types that contain telomeres?
Which events listed are part of mitosis? 1 interphase 2 prophase 3 cytokinesis
The photomicrograph shows 17 cells in different stages of the mitotic cell cycle. [Photomicrograph of cells in different mitotic stages, with cell ...
The flow diagram shows some of the stages in the replication of a lagging strand of DNA. [Flow diagram: 'The DNA double helix begins to unwind.' ->...
In a gene, the 20 common amino acids are each coded for by three bases in adjacent nucleotides. Why is there a difference between the number of ami...
How is a primary transcript modified to form mRNA?
The diagram shows protein synthesis in a prokaryote. [Diagram of protein synthesis in a prokaryote showing DNA, cell wall, X, Y, tRNA 1, tRNA 2, mR...
The photomicrographs show sections of two organs of a plant. [Two photomicrographs (A and B) of plant organ sections] Which letter identifies a cel...
Which row correctly describes the pressure in the xylem and the water potential in the root hair cells used in the transport of water in a transpir...
Which row correctly identifies the definitions for each of the key terms used in transpiration?
Which combination of features is characteristic of a phloem sieve tube element immediately after it is loaded from a source?
Which blood vessel carries blood with the lowest pressure?
The photomicrograph shows cells found in mammalian blood. [Photomicrograph of mammalian blood cells, with one cell labelled P] What is cell P?
The diagram shows the Bohr shift in actively respiring cells. [Graph showing percentage saturation of haemoglobin with oxygen against partial press...
The bar chart shows the mean thickness of the walls of the main chambers in a mammalian heart. [Bar chart showing mean wall thickness /mm for heart...
The diagram shows parts of the gas exchange system in humans and the associated cells or structures. [Boxes with labels: alveolus, bronchiole, bron...