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 St. Lawrence river in Canada has been identified as an area with very high biodiversity. (b) The St. Lawrence river is rich in species of aquat...
Fig. 3.1 shows a red squirrel, Sciurus vulgaris. This species is native to the British Isles, meaning it has lived there for at least 10000 years. ...
Explain the importance of the myelin sheath in the transmission of action potentials.
Galactosaemia is a rare genetic disease in which the build-up of the monosaccharide galactose can result in an enlarged liver, kidney failure and b...
Fig. 8.1 is a diagram summarising the role of the nervous and endocrine systems in the control of blood glucose concentration. hypothalamus neurone...
The enzyme urease catalyses the breakdown of urea into carbonate ions and ammonium ions as shown in Fig. 1.1. urease urea + water --[urease]--> car...
Barley is often grown in soils that are high in salt (sodium chloride). Researchers tested the salt tolerance of two varieties of barley, X and Y, ...
The enzyme lactase hydrolyses the disaccharide lactose to glucose and galactose. This enzyme is produced in the small intestine of mammals and by s...
In some countries crops are irrigated using water containing salt (sodium chloride). This makes the soil saline (salty) which means it contains suf...
What is the diameter of a typical prokaryote, such as Streptococcus?
A specimen of plant tissue is first observed under a microscope using red light with a wavelength of 650 nm. The same specimen is then observed und...
Which structures are present in a Vibrio cholerae cell?
The removal of a plant cell wall by enzyme digestion leaves an intact membrane-bound structure called a protoplast. Which statement explains why pr...
Which statements are correct for a green plant? 1 ATP is produced by mitochondria. 2 ATP is produced by chloroplasts. 3 ATP forms part of the DNA.
Which processes occur in eukaryotes and prokaryotes? 1 hydrolysis 2 mitosis 3 transcription 4 translation
A sample of a solution was tested for reducing sugar and the result was negative. Another sample of the same solution was then tested for non-reduc...
Which row correctly identifies three polysaccharides
Which diagram shows where a peptide bond would be formed?
Which statements about collagen molecules are correct? 1 Both types of secondary structure occur within the molecules. 2 Large numbers of hydrogen ...
The protein glutenin gives bread dough its elasticity. The diagram represents a polypeptide of glutenin. What describes the structure of glutenin?
Which diagram correctly shows hydrogen bonding between water molecules? The symbol δ indicates the partial charge on an atom in the water molecule.
Aspirin inhibits an enzyme by reacting with an amino acid that forms an essential part of the 3D structure of the enzyme. Part of the aspirin molec...
The table shows the Michaelis-Menten constant, K_m, for three enzymes. Which interpretation of the information is correct?
The diagram is a drawing from an electron micrograph of a typical animal cell. How many layers of phospholipids will a molecule of oxygen cross to ...
How could water molecules cross the cell surface membrane of animal cells? 1 carrier proteins 2 channel proteins 3 cholesterol molecules
The diagram shows a xylem vessel in a root and four adjacent parenchyma cells. As water moves up the xylem vessel, it is replaced by water from cel...
Agar cubes can be used to demonstrate the effect of changing surface area to volume ratio on diffusion. Three different agar cubes made using a dil...
The photomicrograph shows cells in different stages of mitosis. Which statements are correct? 1 Cell T shows metaphase. 2 DNA replication occurs in...
Which changes in a group of mammalian cells, dividing by mitosis, would be necessary for the formation of a tumour? 1 Mitosis is no longer inhibite...
Which row shows some of the events during a mitotic cycle in the correct time sequence?
What is the maximum number of hydrogen bonds in a length of DNA containing 700 base pairs?
What is the common component of the three molecules RNA, DNA, and ATP?
Photomicrographs of a dicotyledonous plant root, stem and leaf are shown. Which row is correct for the labels 1 to 5 on the photomicrographs?
Which features apply to phloem sieve tube elements and to xylem vessel elements? 1 no cytoplasm 2 no end walls 3 no nucleus
Which statement correctly describes an event in the process of mass flow in phloem sieve tube elements?
The diagram shows a potato tuber at different stages. 1 dormant tuber (not growing) 2 sprouting roots and shoots 3 growing roots and shoots 4 makin...
What describes the role of the atrio-ventricular node of the heart?
The diagram shows pressure changes during the cardiac cycle. Which arrow indicates ventricular systole?
Which process can be carried out by a mature red blood cell?
Haemoglobin can bind to carbon dioxide, carbon monoxide and oxygen. Which statement about the binding sites of haemoglobin is correct?
Which tissues are present in a bronchus?
Cigarette smoke contains tar. Which statements describe the effect of tar on the respiratory system? 1 Tar causes goblet cells to increase the secr...
Symptoms of chronic obstructive pulmonary disease (COPD) include a cough, breathlessness and chest infections. Some of the changes in the lungs tha...
Which statements about infectious diseases are correct? 1 Cholera has a vaccine available and is caused by a bacterial pathogen of the Vibrio group...
The antibiotic tetracycline binds to the small subunit of bacterial ribosomes, stopping protein synthesis. Bacteria have become resistant to tetrac...
The graph shows how the body reacts following exposure to an antigen for the first and second time. What is the direct cause of the increase in ant...
Why has it proved difficult to develop an effective vaccine against malaria?
Fig. 1.1 shows the human gas exchange system. [Figure 1.1]
Fig. 2.1 shows the disaccharide lactose, which is found in milk. [Figure 2.1]
(a) Fig. 3.1 is a transmission electron micrograph showing two adjacent cells in a leaf. [Figure 3.1]