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.
Some babies are born with a hole between the right and left atria. These babies have an increased number of red blood cells. What is the reason for...
In the lungs, oxygen and carbon dioxide pass through cell membranes by diffusion. Which row is correct?
Which describes how substances in cigarette smoke increase the risk of developing atherosclerosis? 1 Carbon monoxide damages the endothelium of the...
Which flow diagram correctly describes the effect of tar entering the lungs?
Which could directly reduce the surface area available for gas exchange in human lungs? 1 emphysema 2 lung cancer 3 smoking
The malarial parasite, Plasmodium, infects red blood cells and breaks down haemoglobin. Free haem groups are toxic to Plasmodium and the parasite c...
During a primary immune response, the following events occur. 1 Some B-lymphocytes form plasma cells. 2 B-lymphocytes with the specific cell surfac...
Which statement concerning the defence in the body against infectious disease is not correct?
An antiserum to a snake toxin can be obtained by injecting the toxin into a horse. The antiserum is made from blood plasma taken from the horse a f...
The flow of nutrients in an ecosystem is shown in the diagram. [Figure 38.1] Which letter represents decomposers?
An insect eats only the leaves of grass. This insect is eaten by carnivorous beetles. Which ecological terms are described in this information abou...
A gardener has a waterlogged garden showing poor growth. He decides to drain it in an attempt to reduce the numbers of some harmful bacteria. Which...
What is the diameter of a typical plant cell?
A specimen is viewed under a microscope using green light with a wavelength of 510 nm. If the same specimen is viewed under the same conditions, bu...
What is the function of plasmodesmata in plant cells?
Which size of ribosome is found in both chloroplasts and mitochondria?
Which function is correct for the description of the cell structure?
Ribosomes consist of two subunits, each containing rRNA. An analysis of all the 70S ribosomes from a single cell of the bacterium, Escherichia coli...
Which type of bond holds together an α-helix or β-pleated sheet of a protein?
What describes only the quaternary structure of haemoglobin? 1 α-helix 2 a dipeptide 3 a globular structure 4 the specific order of amino acids 5 f...
The statements are about the properties of water. 1 ability to form hydrogen bonds with other molecules 2 less dense when frozen 3 able to hold a l...
Which bonds hold together the structure of cellulose? 1 glycosidic 2 hydrogen 3 ionic
Which bonds are found in glycogen?
Solutions of biological molecules are tested for sugars. The table shows the colours of the solutions after testing. Which may contain non-reducing...
Which levels of protein structure are always involved when competitive and non-competitive inhibitors bind to enzymes?
Which statements are true about the optimum temperature of all enzymes? 1 It is the temperature at which the enzymes work best. 2 It is the highest...
Which description of cell surface membrane permeability is correct?
The diagram represents a cell surface membrane. Three pathways through the membrane are shown. Which process is represented by each arrow?
Which set of factors will produce the most fluid cell surface membrane?
The protein p53 is produced in a cell in response to DNA damage. A scientist exposed three groups of cells, X, Y and Z, to different conditions. In...
Which row is correct?
What is needed to transcribe DNA?
In a ribosome, which bond holds together two adjacent amino acids?
The diagram shows part of a DNA molecule. How many hydrogen bonds are involved in holding these strands of DNA together?
Which features of these cells make them suitable for their function?
What is the sequence of events in the translocation of sucrose?
Where does water evaporate from during transpiration?
Which changes to the water potential and the volume of liquid in the phloem occur when amino acids are taken out of a sink in a phloem sieve tube?
Which reaction takes place in a capillary in the lungs?
Which structure is correctly identified?
Resting muscle has a lower respiration rate than active muscle. The graph shows oxygen dissociation curves for haemoglobin at carbon dioxide concen...
What does not help to maximise uptake of oxygen as blood flows through capillaries in the lungs?
What correctly describes the role of elastic fibres in the lungs?
The diagram represents a section through the wall of a bronchus (not to scale). In a person with chronic obstructive pulmonary disease (COPD), what...
The symptoms of two diseases are listed. Which row identifies diseases 1 and 2?
The graph shows the fall in cases of tuberculosis (TB) in a country between 1910 and 2000. Which factors could have contributed to the fall over th...
Which row is correct for cholera?
Which action is taken by a B-lymphocyte activated by an antigen?
The synthesis of specific antibodies in response to vaccination is an example of which type of immunity?
At which stage of a food chain in a tropical grassland is the energy transfer least efficient?