Cambridge Past Paper Questions
Browse 23,045questions from 25 years of O-Level & A-Level exams. Click any question to practice.
The diagram shows pressure changes in the left side of the heart during the cardiac cycle. [Graph showing pressure changes in the left side of the ...
Which components of blood are present in tissue fluid? [Table with columns 'phagocytes', 'some proteins', 'sodium ions'] key: ✓ = present x = not p...
In the lungs, movement of dissolved carbon dioxide out of the capillaries occurs in one of two ways: • by diffusion through the endothelial cells o...
What maintains the steep concentration gradients needed for successful gas exchange in the lungs? 1 Air flow in the alveoli is in the opposite dire...
Where is cartilage tissue always found in the human gas exchange system?
Scientists compared the density of goblet cells in the lungs and the density of mucus in the lungs of three groups of people: • people who do not s...
Which disease does *Mycobacterium bovis* cause?
An antibiotic inhibits the formation of cross-links between the molecules that form cell walls in bacteria. Which statements explain why bacteria a...
Scientists investigated the effect of increasing concentrations of an antibiotic on the development of antibiotic resistance in bacteria. The scien...
What is the correct sequence of events in a primary immune response?
Which statement about the properties of the antigen-binding sites in different antibody molecules is correct?
The diagram shows a stage in monoclonal antibody production. [Diagram showing 'X' + 'cancer cells' -> 'hybridoma cells'] What is represented by X?
Fig. 1.1 is a diagram showing part of a cell surface membrane of an animal cell. [Figure 1.1] Fig. 1.2 is a drawing of a transmission electron micr...
Fig. 2.1 is a diagram of the circulation in a mammal. [Figure 2.1] Fig. 2.2 is a transmission electron micrograph of a cross-section of an arteriol...
A class of students was studying the features of some human pathogens. One of the students constructed a flow chart to identify four different huma...
Fig. 4.1 is a scanning electron micrograph showing the tissue that lines the bronchi in the gas exchange system. Fig. 4.2 is a transmission electro...
The pressure of water vapour inside and outside leaves can be measured. The difference between these pressures is known as the leaf vapour pressure...
Antibodies are produced by plasma cells. Fig. 6.1 shows antigens bound to antigen-binding sites of an antibody molecule. [Figure 6.1] It is estimat...
Smooth muscle is a tissue composed of smooth muscle cells. The cells contain cytoplasm packed with proteins that are involved in contraction and re...
Alveolar macrophages are cells of the immune system that remain in the alveolar region of the gas exchange system. The macrophages protect against ...
Lysozyme is an antibacterial enzyme that was discovered in 1921 by Alexander Fleming, the scientist who discovered penicillin. Lysozyme catalyses t...
In the mesophyll tissue of leaves, products of photosynthesis can be used to synthesise organic compounds, such as the polysaccharide cellulose and...
During interphase of the cell cycle, individual chromosomes cannot be seen within the nucleus. The genetic material is termed chromatin during this...
Some people who are infected with HIV have HIV/AIDS.
The Zika virus is a pathogen that can infect human cells.
Collagen is a fibrous protein that is found in many tissues in animals.
Arteries, capillaries and veins are three types of blood vessel.
Lignin and suberin are polymers that are present in plant tissues.
Cyclin-dependent kinases (CDKs) are enzymes that regulate the cell cycle.
DNA and RNA are polynucleotides.
Plasmolysis may be seen in onion cells that have been put into a sodium chloride solution. Plasmolysis occurs when water moves out of the cells and...
Many plants store starch in their roots. The amount of starch present in roots can vary with the seasons. In the summer months, when plants are act...
Some fruits contain protease enzymes. These enzymes can denature the proteins in milk, causing the milk to clot. You will investigate the effect of...
K1 is a slide of a stained transverse section through a plant leaf.
Yeast cells contain enzymes that catalyse the breakdown of sugars, such as glucose and sucrose, to produce ethanol and carbon dioxide. As the sugar...
L1 is a slide of a stained transverse section through a plant stem.
Oxygen is needed for aerobic respiration in cells. In eukaryotic cells, the mitochondrion is the organelle used for aerobic respiration.
Coordination in humans involves two main systems: the nervous system and the endocrine system. Paracrine cell signalling is a third way in which co...
Stomata in leaves respond to changes in environmental conditions by opening and closing. This regulates carbon dioxide uptake and water loss.
White-clawed crayfish, Austropotamobius pallipes, live in rivers and lakes in Europe. In the 1850s, the North American signal crayfish, Pacifastacu...
Photosynthesis is the energy transfer process that occurs in chloroplasts. Fig. 5.1 shows some biochemical events that occur in a chloroplast durin...
Many different genes are involved in the production of pigments in mammals. One example is the TYR gene.
It has been hypothesised that the mutation rate of an animal species may affect how fast animals of that species age and how long they live (lifesp...
Bears are several species of mammal in the family Ursidae. Climate change and loss of habitats due to human activity have reduced the size of some ...
The harlequin ladybird, Harmonia axyridis, is an insect that shows discontinuous variation in colour pattern and continuous variation in body size.
Humans detect the sweet taste of sucrose sugar using chemoreceptor cells in taste buds on the tongue. The red admiral butterfly, Vanessa atalanta, ...
Osmoregulation is the control of the water potential of body fluids such as blood.
Variation exists in populations of a species and this may provide the opportunity for evolution to occur.
The tortoise beetle, Chelymorpha alternans, is an insect found in Panama that has several different colour patterns. [Figure 3.1] Researchers have ...
Genes have a role in determining the overall phenotype of an organism.