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 row correctly identifies three polysaccharides
Which diagram shows where a peptide bond would be formed?
Which statements about collagen molecules are correct? 1 Both types of secondary structure occur within the molecules. 2 Large numbers of hydrogen ...
The protein glutenin gives bread dough its elasticity. The diagram represents a polypeptide of glutenin. What describes the structure of glutenin?
Which diagram correctly shows hydrogen bonding between water molecules? The symbol δ indicates the partial charge on an atom in the water molecule.
Aspirin inhibits an enzyme by reacting with an amino acid that forms an essential part of the 3D structure of the enzyme. Part of the aspirin molec...
The table shows the Michaelis-Menten constant, K_m, for three enzymes. Which interpretation of the information is correct?
The diagram is a drawing from an electron micrograph of a typical animal cell. How many layers of phospholipids will a molecule of oxygen cross to ...
How could water molecules cross the cell surface membrane of animal cells? 1 carrier proteins 2 channel proteins 3 cholesterol molecules
The diagram shows a xylem vessel in a root and four adjacent parenchyma cells. As water moves up the xylem vessel, it is replaced by water from cel...
Agar cubes can be used to demonstrate the effect of changing surface area to volume ratio on diffusion. Three different agar cubes made using a dil...
The photomicrograph shows cells in different stages of mitosis. Which statements are correct? 1 Cell T shows metaphase. 2 DNA replication occurs in...
Which changes in a group of mammalian cells, dividing by mitosis, would be necessary for the formation of a tumour? 1 Mitosis is no longer inhibite...
Which row shows some of the events during a mitotic cycle in the correct time sequence?
What is the maximum number of hydrogen bonds in a length of DNA containing 700 base pairs?
What is the common component of the three molecules RNA, DNA, and ATP?
Photomicrographs of a dicotyledonous plant root, stem and leaf are shown. Which row is correct for the labels 1 to 5 on the photomicrographs?
Which features apply to phloem sieve tube elements and to xylem vessel elements? 1 no cytoplasm 2 no end walls 3 no nucleus
Which statement correctly describes an event in the process of mass flow in phloem sieve tube elements?
The diagram shows a potato tuber at different stages. 1 dormant tuber (not growing) 2 sprouting roots and shoots 3 growing roots and shoots 4 makin...
What describes the role of the atrio-ventricular node of the heart?
The diagram shows pressure changes during the cardiac cycle. Which arrow indicates ventricular systole?
Which process can be carried out by a mature red blood cell?
Haemoglobin can bind to carbon dioxide, carbon monoxide and oxygen. Which statement about the binding sites of haemoglobin is correct?
Which tissues are present in a bronchus?
Cigarette smoke contains tar. Which statements describe the effect of tar on the respiratory system? 1 Tar causes goblet cells to increase the secr...
Symptoms of chronic obstructive pulmonary disease (COPD) include a cough, breathlessness and chest infections. Some of the changes in the lungs tha...
Which statements about infectious diseases are correct? 1 Cholera has a vaccine available and is caused by a bacterial pathogen of the Vibrio group...
The antibiotic tetracycline binds to the small subunit of bacterial ribosomes, stopping protein synthesis. Bacteria have become resistant to tetrac...
The graph shows how the body reacts following exposure to an antigen for the first and second time. What is the direct cause of the increase in ant...
Why has it proved difficult to develop an effective vaccine against malaria?
Fig. 1.1 shows the human gas exchange system. [Figure 1.1]
Fig. 2.1 shows the disaccharide lactose, which is found in milk. [Figure 2.1]
(a) Fig. 3.1 is a transmission electron micrograph showing two adjacent cells in a leaf. [Figure 3.1]
Fig. 4.1 is a photomicrograph of a cross-section of a tubular structure in the kidney made from epithelial cells. [Figure 4.1]
(a) Fig. 5.1 shows the structure of a prokaryotic cell. [Figure 5.1]
(a) Haemoglobin is a globular protein which is able to transport oxygen and is soluble in water.
Fig. 1.1A is a photomicrograph of healthy lung tissue. Fig. 1.1B is a photomicrograph of lung tissue from a person with emphysema, a chronic obstr...
Woolly foxglove, Digitalis lanata, shown in Fig. 2.1A, and common oleander, Nerium oleander, shown in Fig. 2.1B, are plants grown for the attractiv...
The response of the human body to tissue damage depends on the types of tissues involved. Epithelial tissue, liver tissue and cardiac muscle tissue...
Viruses share common structural features. Some viruses, such as human immunodeficiency virus (HIV), also have an outer envelope as part of their st...
DNA and RNA are nucleic acids.
As a red blood cell matures, cell organelles are lost from the cell. This provides more space for the haemoglobin molecules that have been synthesi...
Aphids are small insects which feed directly on phloem sap. The salivary glands of aphids have secretory cells that make and release a variety of p...
Proteins are macromolecules composed of many amino acids.
(a) Fig. 3.1 is a diagram of a monomer of the nucleic acid, messenger RNA. [Figure 3.1]
Describe the roles of the sinoatrial node (SAN) and the atrioventricular node (AVN) in the initiation and control of the cardiac cycle.
The bacteria that cause tuberculosis (TB) can be found in many parts of the body including the lungs.
(a) As part of a study of the mitotic cell cycle, a student made stained sections of a root tip of onion, Allium cepa, and observed them with a lig...
Plant cells contain enzymes which catalyse some of their metabolic reactions. Some of these enzymes catalyse the release of oxygen from hydrogen pe...