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 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?
A farmer grows a different crop in a field each year for three years. In the fourth year he grows a leguminous crop, such as clover, and then ploug...
Of the prey consumed by the lion, into which box does the largest amount of energy flow?
A student was presented with a photomicrograph of a cell organelle. The magnification of the photomicrograph is known. Which calculation of the act...
Which statements about both mitochondria and chloroplasts are correct? 1 They contain 80S ribosomes. 2 They contain circular DNA molecules. 3 They ...
A scientist carried out an experiment to separate the organelles in an animal cell by mass. The scientist mixed the cells with a buffer solution wh...
Which row shows the monomer and type of bond that form the polymer?
Which biological molecules always contain the element nitrogen?
Which statement about the quaternary structure of proteins is correct?
Which set of statements correctly describes haemoglobin?
The diagrams show different types of bond found in biological molecules. [Figure 9.1] Which bonds are found in proteins with a tertiary structure?
In two investigations, the rate of an enzyme-catalysed reaction was measured in the presence of either a competitive inhibitor or a non-competitive...
Two enzymes, X and Y, were used in an experiment. Enzyme X was from bacteria that live in rivers and lakes at temperatures from 5°C to 20 °C. Enzym...
What is a function of the cholesterol in a cell surface membrane?
Which roles of the cell surface membrane are a result of the properties of the phospholipids? 1 to allow cytokinesis to occur in mitotic cell divis...
Which statements about active transport are always correct? 1 It does not require a membrane. 2 It occurs against the concentration gradient. 3 It ...
There is a high concentration of molecule X outside the cell which enters the cell by facilitated diffusion. The results of measuring the concentra...