Cambridge & Pearson Edexcel Past Paper Questions

Collagen is a major component of the cartilage found in some of the structures of the human gas exchange system. Cells that synthesise and secrete ...

In most plants, sucrose is the main sugar that is transported from sources to sinks. Fig. 5.1 shows part of one pathway that is used in plant cells...

The mitotic cell cycle in dividing cells is very carefully controlled. Some of the stages have been completed for you. At various points during the...

Water and mineral ions are transported up the stem of a plant to the leaves within xylem vessels. Some water and mineral ions can pass out of xylem...

In 2016, the highest number of cases of malaria and deaths caused by the disease were in sub-Saharan Africa. In many areas of sub-Saharan Africa, m...

Fig. 3.1 is a photomicrograph of a section through two different types of blood vessels, X and Y. [Figure 3.1] Name the two types of blood vessel s...

Saccharomyces cerevisiae is a unicellular fungus that is important in the brewing and baking industries. Fig. 4.1 is a diagram of a transmission el...

Blood cells are formed from tissue stem cells in the bone marrow. These bone marrow stem cells go through a number of mitotic cell cycles to form t...

A student carried out an investigation to estimate the water potential of potato tissue. The main steps in the procedure and in the analysis of res...

Invertase is an enzyme found in honey. Invertase breaks down sucrose into reducing sugars, as shown in Fig. 1.1. sucrose invertase reducing sugars ...

Water moves through xylem vessel elements in plants. The diameter of xylem vessel elements varies between different species of plant. You will meas...

Energy drinks contain a high concentration of carbohydrates, such as glucose, as a source of energy. Glucose is a monosaccharide which can be quick...

In mammals, the hormone ACTH is released from the anterior pituitary gland. ACTH stimulates the cells of the adrenal glands to synthesise the hormo...

The patty pan squash plant, Cucurbita pepo, produces edible fruits that vary in colour. (a) The colour of the fruits is controlled by two genes, A/...

Cats are members of the Felidae family. Two genera of Felidae are Leopardus and Panthera. (a) The genus Leopardus consists of species of wild cats ...

Mitochondrial complex I is a large enzyme complex that forms part of the electron transport chain. The enzyme is composed of many different polypep...

Yeast cells are unicellular eukaryotes. Yeast cells respond to changes in the concentrations of the sugars galactose and glucose by switching on ge...

(a) At the end of glycolysis in mammalian muscle tissue, pyruvate is formed. Pyruvate can be further metabolised along two different pathways, path...

(a) Structures, processes and compounds involved in photosynthesis in C4 plants include: A - carbon dioxide B - phosphorylation C - palisade cells ...

(a) Sampling is used to find out the variety of species in an ecosystem and the size of the population of each species. A study was carried out to ...

Describe how the polymerase chain reaction is used to clone and amplify DNA.

Describe the ultrastructure of a striated muscle fibre.

The enzyme alanine transaminase (ALT) is found in the liver. The function of ALT is to convert the amino acid α-ketoglutarate into another amino ac...

The summer squash plant, Cucurbita pepo, produces edible fruits that vary in shape. [Figure 2.1] shows the fruits of three different varieties of s...

A subspecies is a genetically distinct population within a species that has some phenotypic differences from the rest of the species, but is not ye...

Gene therapy can be used to treat some genetic disorders. An appropriate vector is chosen to carry the normal allele into the target cell. Three ty...

Yeast cells respond to changes in glucose concentration in their environment by using transcription factors to switch off genes. When glucose is pr...

Thyrotoxic myopathy (TM) is a neuromuscular disorder caused by overproduction of the thyroid hormone thyroxine. One of the main symptoms of TM is m...

Define the term respiratory quotient (RQ).

Most organisms are classified according to a taxonomic hierarchy. The hierarchy is shown in [Figure 8.1] but the group names are not in the correct...

The courgette plant, Cucurbita pepo, produces edible fruits that vary in colour and shape. Fruit colour in courgettes is controlled by the gene A/a...

Diabetes insipidus (DI) is a condition in humans that causes a person to have an excessive thirst, which leads to increased drinking. One form of D...

The collared flycatcher, Ficedula albicollis, and the pied flycatcher, F. hypoleuca are two closely related species of bird. DNA analysis has shown...

Lung epithelial cells have a thin layer of watery mucus on their surface. The normal allele of the CFTR gene codes for a transport protein that tra...

Yeast cells are unicellular eukaryotes that respond to the presence and absence of different sugars by switching genes on or off. One example of th...

Structures and compounds involved in the light dependent stage of photosynthesis are listed, A to J. A – thylakoid membrane B – starch grain C – c...

Fig. 7.1 shows part of the process of respiration in a mitochondrion. [Figure 7.1] With reference to Fig. 7.1, name: area A process B substance C

Sampling can be used to find the distribution and abundance of species in an area. Students sampled a rocky shore from a high tide area to a low ti...

Chlorella is a green, single-celled protoctist that is photosynthetic. Some students immobilised cells from a culture of this protoctist using the ...

The cotton bollworm, Helicoverpa armigera, is an insect pest of cotton. The adult cotton bollworm is a moth. The adult female moth lays eggs on cot...

Woodlice are small invertebrates that live in cool, damp places under wood and stones. Some students determined the respiration rate of woodlice at...

Cotton bollworms, Helicoverpa spp., are insect pests of cotton. Adult cotton bollworms are moths. The adult female moths lay eggs on cotton plants....

Some students decided to find the respiratory quotient (RQ) of germinating pea seeds. Pea seeds germinate best at temperatures between 13°C to 18°C...

The cotton bollworms, Helicoverpa armigera (old world bollworm) and Pectinophora gossypiella (pink bollworm), are insect pests of cotton. Adult cot...

Which row describes the membranes surrounding each cell structure?

The mean width of mitochondria in an electron micrograph is 6 mm. The magnification of the electron micrograph is ×9600. What is the actual mean wi...

Which sequence shows the correct order of some of the stages in the production and secretion of an enzyme?

Different antibiotics function in different ways. Ideally, the antibiotic kills the bacteria, but does not harm the infected human. One type of ant...

A prokaryotic cell is 5.0 µm in length. A virus particle is 300 nm in length. How many times larger is the prokaryotic cell compared to the virus p...

A student carries out a semi-quantitative test with Benedict’s solution. Which statement about this procedure is correct?