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.
A patient with kidney failure can be given a kidney transplant. In a kidney transplant, a healthy kidney is taken from another person and put into ...
The diagram shows the simplified structure of an antibody. [Figure 40.1] Which statement is correct?
Scientists measured the concentration of sodium ions and potassium ions in the red blood cells and in the blood plasma of a group of people. The re...
Fig. 2.1 is a transmission electron micrograph showing a section of a specialised epithelial cell found in the lining of the stomach. This cell pro...
Plants have specialised cells for the efficient transport of assimilates. (a) Table 3.1 shows some of the features of two different types of cell f...
Some people who are infected with HIV develop HIV/AIDS. (a) Fig. 4.1 shows the number of people that have been newly infected with HIV (new infecti...
Fig. 5.1 is a photomicrograph of a transverse section of a bronchus in the lungs. [Fig. 5.1]
State the name of the phase of the mitotic cell cycle during which DNA replication occurs.
During interphase and mitosis of the cell cycle, the chromosomes within a cell go through a number of changes. Each chromosome is composed of DNA c...
Keratin is the structural protein in feathers of birds. Keratin polypeptides are composed of a high proportion of cysteine amino acids, which have ...
The liver receives blood from the hepatic artery and from the hepatic portal vein. The hepatic portal vein transports blood from the digestive syst...
The alveoli of the lungs are the main gas exchange surface in humans.
Tuberculosis (TB) is an infectious disease caused by a bacterium. In the majority of people, only the lungs are affected. In most cases, the transm...
Water that is absorbed from the soil solution by the roots of a plant enters xylem vessels and is transported to the leaves and buds. Fig. 6.1 show...
You will investigate the effect of temperature on the production of carbon dioxide gas by yeast cells. Yeast cells contain enzymes that break down ...
Yeast cells contain enzymes that hydrolyse sucrose into reducing sugars, as shown in Fig. 1.1. enzymes in yeast cells sucrose → reducing sugars F...
Some organisms carry out respiration in anaerobic conditions when oxygen is not available or when there is a low concentration of oxygen. In yeast ...
Yeasts are unicellular organisms from the kingdom Fungi. Saccharomyces cerevisiae is one species of yeast that can carry out either asexual reprodu...
Research suggests that selective breeding began about 10000 years ago. Selective breeding has been important in satisfying the global demand for food.
A marker gene can be used when a gene of interest is introduced into a plant by genetic engineering.
The fruit fly, Drosophila melanogaster, has autosomal genes for body colour and wing shape. Gene B/b is involved in the production of body colour:...
When blood glucose concentration decreases, glucagon is released by the pancreas into the blood and is transported to the cells.
There are many mitochondria located in the presynaptic knobs of neuromuscular junctions and in the sarcomeres of muscle fibres of striated muscle. ...
Non-cyclic photophosphorylation occurs in the light-dependent stage of photosynthesis. Outline the main features of non-cyclic photophosphorylation.
Antidiuretic hormone (ADH) is involved in the maintenance of a constant blood water potential. A student drank 0.5 dm³ of water and the concentrati...
The passage outlines one method of estimating the size of an animal population. Complete the passage by using the most appropriate scientific terms...
Fruits in the diet can be a source of vitamins, such as vitamin C and vitamin A, which are important in maintaining good health. Vitamin A is a gro...
Trypsin is a protease enzyme. A student compared the activity of trypsin from two different species: the Atlantic salmon, Salmo salar, and the dome...
Rocky shore ecosystems are found in some coastal regions. These ecosystems are inhabited by many different species of algae and animals. Twice each...
Abscisic acid (ABA) is a plant hormone that influences the growth and development of plants. Salicylic acid (SA) is a plant hormone that interacts ...
A light microscope is used to observe two structures that are 200nm apart on the slide. What is the actual distance between the two structures when...
A cell is shown in the micrograph. Which statement explains how it is possible to identify the type of microscope used to produce the micrograph?
Which statement supports the fact that mature plant cells contain organelles that carry out the same role as lysosomes?
Which cell structures may contain cisternae?
The diagram shows some cell structures of one type of cell. Which labelled cell structures are present in typical eukaryotic cells and typical bact...
The diagram shows part of a collagen fibril made of collagen triple helices. The collagen triple helices are linked to each other by one type of bo...
The table shows some information about the polypeptides that make up haemoglobin. α-globin: total number of amino acid residues in polypeptide chai...
Which feature of glycogen distinguishes it from starch?
The diagram shows a biological molecule. Which molecules would be produced if this biological molecule was hydrolysed?
A mixture of glucose and starch solutions was placed in a length of dialysis (Visking) tubing and the tubing sealed. The tubing was then placed in ...
The initial rate of a reaction catalysed by an enzyme was measured at various substrate concentrations. Which graph shows the effect of a low conce...
Gout is a type of arthritis in which small uric acid crystals form inside and around the joints. It causes sudden attacks of severe pain and swelli...
Phospholipids are formed in a similar way to triglycerides. A sample contained six phospholipid molecules. • The molecular weight of a phosphate io...
Which statements about phospholipids in cell surface membranes are correct? 1 Fatty acid tails allow most ions to pass through the membrane. 2 Hydr...
In an experiment, pieces of onion epidermis are put into three different concentrations of sucrose solutions, P, Q and R. The pieces of onion are l...
The electron micrograph shows rod-shaped bacteria. The actual length of the bacterium is 2.0 µm and the diameter is 0.5 µm. Assume that the bacteri...
Chickens have 78 chromosomes in the nucleus of a body cell. How many DNA molecules are there in a chicken body cell at the start of prophase of mit...
The photomicrograph shows cells undergoing mitosis. Which statement describes what will happen next in cell X?
Which processes occur in bone marrow cells that are in a mitotic cell cycle? 1 Phosphate groups bind to ADP molecules to form ATP. 2 Bonds form bet...
A polypeptide molecule contains the amino acid sequence: glycine - leucine – lysine – valine. The table shows DNA triplets for these amino acids. g...