Cambridge Past Paper Questions
Browse 23,045questions from 25 years of O-Level & A-Level exams. Click any question to practice.
The graph shows the energy levels involved in an enzyme-catalysed reaction. Substrate molecules X and Y combine to give product Z. Which arrow show...
Which roles of the cell surface membrane result from the properties of the phospholipids? 1 to allow cytokinesis to occur in mitotic cell division ...
Which factors can be changed to affect the rate of facilitated diffusion across a cell surface membrane? 1 the surface area of the membrane 2 the c...
The diagram shows an experiment using a model cell to investigate the movement of substances. [Figure 16.1] Which statements are correct? 1 There i...
Human chromosomes have different parts. Some parts are more numerous than others. Which parts are listed in order from most numerous to least numer...
The diagram represents the cell cycle of a human cell. During the cell cycle the number of chromatids changes. [Figure 18.1] Which row is correct f...
A single skin cell was isolated and transferred to growth medium in a sterile Petri dish. The Petri dish was incubated for 16 days. During this tim...
A short piece of DNA, 18 base pairs long, was analysed to find the number of nucleotide bases in each of the polynucleotide strands. Some of the re...
The diagram shows a strand of DNA and mRNA during transcription. [Figure 21.1] Which row correctly identifies 1, 2 and 3?
Two students were discussing the involvement of DNA and RNA in transcription and translation. • Student 1 always stated correct facts. • Student 2 ...
Which descriptions of the adaptations of xylem vessel elements to their function are correct? 1 They have pits between vessels allowing water to pa...
The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause the diame...
A student wanted to find out the rate of transpiration using a potometer as shown. [Figure 25.1] The student was told to work out a value for trans...
In plants, assimilates such as sucrose are loaded from source cells into sieve tube elements. The assimilates are then transported from source to s...
The sinoatrial node initiates the cardiac cycle. What is the correct order in which the chambers of the heart contract?
The graph shows pressure changes in different parts of the heart during a mammalian cardiac cycle. W, X, Y and Z indicate when a valve opens or clo...
What is the main reaction occurring in blood capillaries at the gas exchange surface in a human lung?
Which reactions take place in blood that is passing through active tissues? 1 HbO₈ ⇌ Hb + 4O₂ 2 HbO₈ + H⁺ → HHb + 4O₂ 3 HCO₃⁻ + H⁺ → H₂CO₃ 4 H₂O + ...
Which row shows the tissues that are present in the wall of the trachea and in the wall of the bronchus? [Figure 32.1]
In some cases where a person has lung disease, the partial pressure of oxygen in the pulmonary veins is less than the partial pressure of oxygen in...
How many times must a molecule of carbon dioxide pass through a cell surface membrane as it diffuses from the plasma, through a cell in the capilla...
Which disease is spread by a vector?
Which statement explains why a one-dose vaccination programme for measles has not yet eliminated the disease?
What has contributed to the increase in antibiotic resistance in bacteria? 1 increased use of vaccines for animal diseases 2 mutations in bacterial...
Which statements correctly describe lymphocytes? 1 Each B-lymphocyte has the ability to make several types of antibody molecules. 2 Some B-lymphocy...
A country introduced a measles vaccination during a measles epidemic. Later, it was realised that vaccinated children were more likely to survive c...
Fig. 1.1 is a transmission electron micrograph of cells from duckweed, Spirodela oligorrhiza. [Figure 1.1]
Fig. 2.1 shows three molecules of water. [Figure 2.1] The human enzyme, salivary amylase, is composed of one polypeptide. Fig. 2.2 represents the s...
Visking tubing can be used to investigate the properties of cell membranes. A student carried out an experiment to investigate osmosis using Viskin...
The induced-fit hypothesis and the lock-and-key hypothesis are used to describe the mode of action of enzymes. Radish plants contain the enzyme per...
Much success was made in reducing the number of cases of malaria between 2000 and 2015.
Lysosomes are cell structures that contain enzymes known as acid hydrolases. Fig. 6.1 shows some processes that occur in animal cells. [Figure 6.1]
(a) Fig. 1.1 is a photomicrograph of a region of eukaryotic tissue. Some of the cells are in stages of mitosis. E F Fig. 1.1
Sugars are transported within phloem sieve tubes from a source, such as a mature leaf, to a young leaf, which acts as a sink. The young leaf also n...
In mammals, some cell signalling molecules are steroid (lipid) hormones. These hormones are transported in the bloodstream to reach capillary netwo...
A person who is exposed to tobacco smoke is at greater risk of lung cancer and chronic obstructive pulmonary disease (COPD). Many people with COPD...
Fig. 5.1 is a transmission electron micrograph showing parts of two plant cells. The function of the middle lamella is cell-to-cell adhesion. The m...
The diseases myasthenia gravis (MG) and HIV/AIDS both involve disorders of the immune system.
The Golgi body, rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER) form part of the internal membrane system of a cell. The m...
Smallpox, measles and HIV/AIDS are infectious diseases caused by different viruses. These different viruses share some structural features.
HIV protease is an enzyme composed of two identical polypeptide chains. Each polypeptide chain is 99 amino acids long. During translation, the amin...
Phloem sap is transported within phloem sieve tubes.
Fig. 5.1 shows four types of cell that can be seen in a prepared slide of blood taken from a mammal. [Figure 5.1]
The best time to obtain a clear image of chromosomes during a mitotic cell cycle is during the metaphase stage. Fig. 6.1 is a scanning electron mic...
J1 is a slide of a stained transverse section through a plant leaf.
Some biological molecules produce a colour change when tested with a specific reagent. You will investigate which biological molecules are present ...
L1 is a slide of a stained transverse section through a plant leaf. (a) Set up the microscope so that you can observe the section on L1. Use a shar...
Photosynthesis is a complex process involving the transfer of light energy into chemical energy. The rate of photosynthesis is affected by many env...
All organisms respire to release energy from energy-rich molecules such as glucose. Some factory workers in the early 20th century were exposed to ...
In 2014, scientists published a phylogenetic (evolutionary) tree diagram showing how and when different groups of insects developed from ancestral ...