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. 5.1 shows a cat displaying the recessive phenotype for two unlinked genes. • H/h controls hair length. The allele for short hair is dominant t...
Structures and compounds involved in respiration in anaerobic conditions include: A – pyruvate B - reduced NAD C - ethanol D - carbon dioxide E - c...
Two methods of estimating the water potential of plant tissue are described. Method 1: Pieces of tissue are left in sucrose solutions of different...
Biodiversity is important in maintaining the stability of an ecosystem. Biodiversity can be reduced by the introduction of new species to an ecosys...
Some students observed a flowering plant and noticed that the flower was supported by a long stalk. To investigate how the stalk supported the flow...
Water hyacinth, Eichhornia crassipes, is a plant that grows on the surface of waterways such as rivers and lakes and is an alien species in many pa...
Two methods of estimating the water potential of plant tissue are described. Method 1: Pieces of tissue are left in sucrose solutions of different ...
A scale bar on an electron micrograph is 2 cm long and represents an actual length of 1 µm. What is the magnification of the electron micrograph?
The eyepiece of a microscope is fitted with an eyepiece graticule and a stage micrometer scale is placed on the microscope. Which statements about ...
Which cell structures are required for the formation of lysosomes and the hydrolytic enzymes that they contain? mitochondria [Figure showing a Venn...
Which cell structures contain rRNA? 1 chloroplast 2 mitochondrion 3 nucleus 4 smooth endoplasmic reticulum
The single-celled organism Thiomargarita namibiensis measures 700 µm in diameter and is enclosed in a cell wall. The genetic material of T. namibie...
A student carried out four tests on a sample of biological molecules. [Table showing test and observation: emulsion cloudy, Benedict's yellow, biur...
Which general formula is correct for monosaccharides such as fructose?
Which statements can be used to describe the structure of cellulose? 1 a polymer of glucose monomers linked by β-1,4 glycosidic bonds 2 a polysacch...
Complete hydrolysis of polysaccharides requires all the glycosidic bonds between the monomers to be broken. Enzyme X only breaks α-1,4 glycosidic b...
Which molecules contain at least two double bonds?
The diagram shows an amino acid. [Figure showing a generic amino acid structure] Which group is changed to produce different amino acids?
Which row is correct about the structure of proteins? [Table describing primary, secondary, tertiary, and quaternary protein structures]
Which graph correctly shows possible changes in energy levels as a chemical reaction progresses with or without an enzyme? [Four graphs (A, B, C, D...
The graph shows the relationship between the concentration of substrate and the rate of an enzyme-catalysed reaction. [Figure showing a graph of ra...
Liver cells contain vesicles that have proteins in their membranes which are specific for the transport of glucose. When these cells need to take u...
A student set up an experiment to investigate diffusion. A block of agar, 1.0 cm × 1.0 cm × 1.0 cm, was stained uniformly with a water-soluble blue...
Which description is correct?
During metaphase, a scientist stains the chromosomes of a diploid animal cell with fluorescent dye to allow the telomeres to be observed. This cell...
The photomicrographs show cells in various stages of the cell cycle. [Figure showing four photomicrographs labeled 1, 2, 3, 4, depicting cell cycle...
Uncontrolled cell division can result in the formation of a tumour. Which part of the cell cycle would take less time during the formation of a tum...
A piece of a DNA molecule contains 84 base pairs. The table shows the number of adenine and cytosine bases in one or both of the DNA strands in thi...
The mRNA sequences of the three stop codons are shown. UAA UAG UGA Which mutation in the template (transcribed) strand of a DNA sequence that codes...
Which features of companion cells are essential to their function? 1 They are connected to the sieve tube elements by plasmodesmata. 2 They have a ...
Which statements about water movement in plants are correct? 1 Water can pass through cellulose cell walls. 2 Water cannot pass through lignified c...
Which sequence of events could lead to mass flow in a phloem sieve tube? 1 Sucrose moves into a sieve tube element. 2 Protons (H+) and sucrose mole...
What will happen as a result of the blood pressure in the right ventricle becoming higher than the blood pressure in the right atrium?
Which statements are correct? 1 Compared with blood, tissue fluid has less protein and no red blood cells. 2 Lymph may contain lipids, carbon dioxi...
What explains how the maximum volume of oxygen is taken up as blood passes through the capillaries of the lungs?
The image shown is a photomicrograph of a transverse section of part of the gas exchange system. [Figure showing a photomicrograph] What describes ...
When a person suffers an asthma attack, the tubes of the gas exchange system narrow and extra mucus is produced. Which changes occur during an asth...
Which flow diagram correctly describes the effect of tar entering the lungs? [Four flow diagrams (A, B, C, D) describing a sequence of events]
Which control measures would reduce the transmission of tuberculosis (TB)? [Table with boiling water before drinking it, antibiotics, vaccination]
Comorbidity is where an individual has two or more diseases or medical conditions at the same time. Some medical conditions are particularly likely...
Which conditions are infectious and result in a high white blood cell count? 1 leukaemia 2 myasthenia gravis 3 TB
Which cell type causes the secondary immune response to be much faster than the primary immune response?
Fig. 1.1 is a transmission electron micrograph of cells from the leaf of a plant. [Figure 1.1]
Fig. 2.1 is a transmission electron micrograph of a transverse section through a blood capillary that is surrounded by actively respiring cells. [F...
Cholera is an infectious disease caused by the bacterial pathogen Vibrio cholerae. (a) Describe how V. cholerae is transmitted from an infected per...
Fig. 4.1 is a drawing made by a student of a plant cell, showing one of the stages of mitosis. [Figure 4.1]
A student investigated the effects of air movement on the rate of transpiration by using a potometer.
Fig. 6.1 is a diagram of sections through the heart showing two stages of the cardiac cycle, A and B. [Figure 6.1]
There are two types of cell, prokaryotic and eukaryotic. Bacterial cells are prokaryotic and plant cells are eukaryotic.
The high blood pressure at the arterial end of a capillary network results in some components of blood leaving the capillaries and forming tissue f...