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.
Which statements about peptide bond formation are correct? 1 The bond formation occurs between a carbon of one amino acid and a nitrogen of the nex...
The diagram shows naturally occurring D-glucose and a form of glucose that can be synthesised in the laboratory, known as L-glucose. [Diagram of D-...
Tests for biological molecules were carried out on three solutions. Each solution contained only one type of biological molecule. The observations ...
Which row describes the expected effect on Vmax and Km when a competitive reversible inhibitor is added to an enzyme-catalysed reaction? [Table wit...
The graph shows the effect of substrate concentration on the rates of reaction of three enzymes, X, Y, and Z. [Graph showing rate of reaction vs su...
Which row correctly identifies the weak and strong bonds in the tertiary and quaternary structure of a typical protein? [Table with columns 'disulf...
Which row correctly describes haemoglobin? [Table with four columns describing aspects of haemoglobin]
Which process always takes place without the involvement of energy from ATP?
The diagram shows the entry of molecule X into a cell. [Diagram of molecule X entering a cell] Which row shows a property of molecule X and the eff...
The electron micrograph shows some human blood cells. [Electron micrograph of human blood cells with one cell labelled X] Which row correctly shows...
A red indicator solution was mixed with agar and the resulting solid was cut into small cylindrical blocks. The blocks were placed in an acid which...
Which metabolic processes will be very active in a cell that has just completed cytokinesis? 1 ATP formation 2 DNA replication 3 protein synthesis
The diagram shows a typical mitotic cell cycle and the point in the cell cycle that has been reached by each of four cells, V, W, X and Y. [Diagram...
The graph shows the mean length of the spindle fibres during mitosis. [Graph showing mean length of spindle fibres over time, with regions A, B, C,...
The mRNA codons ACU, ACC, ACA and ACG all code for the same amino acid, threonine. Which anticodons could specify an amino acid other than threonin...
Which bond formation does DNA polymerase catalyse?
In eukaryotes, the RNA molecules formed during transcription are modified by the removal of non-coding sequences. This is followed by the joining t...
Which row correctly identifies sinks for sucrose transported by mass flow in plants? [Table with columns 'root storage organ', 'growing leaf bud', ...
The diagram shows a transverse section through a transport tissue in a plant. [Diagram of transverse section through a transport tissue with cells ...
Which statement correctly describes the movement of solutes in the symplast pathway?
Which statement helps to explain why water molecules are forced to move through xylem vessel elements as a consequence of transpiration?
The diagram shows the internal structure of the mammalian heart. [Diagram of mammalian heart with locations A, B, C, D labelled] Which letter ident...
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.