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.
In an investigation to find the water potential of onion tissue, some students used epidermal tissue from the storage leaves of a red onion. The va...
Cancer of the blood, including leukaemia and lymphoma, can be caused by mutations of stem cells in the bone marrow. A long-term study into the eff...
Phloem sap is transported from sources to sinks in phloem sieve tubes. Each sieve tube is constructed from phloem sieve tube elements.
Phosphatidate phosphatase (PAP) enzymes have an important role in lipid metabolism. The reaction catalysed by PAP is shown in Fig. 2.1. phosphatida...
During one cardiac cycle: • blood enters the heart from the lungs and from the rest of the body • blood leaves the heart to be transported to the l...
When a section of lung tissue is viewed using a light microscope, it is possible to identify the trachea, the bronchus, the bronchioles and the alv...
Myasthenia gravis and HIV/AIDS both involve disorders of the immune system.
Fig. 6.1 is a transmission electron micrograph of a plant parenchyma cell. [Figure 6.1]
Yeast cells contain an enzyme, catalase, which catalyses the release of oxygen from the substrate hydrogen peroxide. You will investigate the effec...
Starch grains from different types of plant differ in size and shape. Some starch grains have rings on their surfaces. You will now observe and dra...
Fig. 1.1 represents part of the wall of a proximal convoluted tubule (pct) in a kidney nephron. not to scale blood capillary cells of pct B A lumen...
Severe combined immunodeficiency (SCID) is a group of life-threatening diseases. SCID is caused by mutations that prevent the normal function of th...
Flowers of the common morning-glory plant, Ipomoea purpurea, can have several different phenotypes. An example of these flowers is shown in Fig. 3....
The rainbow trout, Oncorhynchus mykiss, is a fish that is bred in commercial fish farms. Rainbow trout that have a blue-silver colour are sold at a...
To identify the function of a gene, scientists can insert (add) a copy of the gene into a plasmid to create recombinant DNA. The plasmid is then tr...
The sea otter, Enhydra lutris, is a marine mammal that lives on the coasts of the North Pacific ocean. Fig. 6.1 shows a sea otter. [Figure 6.1] Tab...
Fig. 7.1 outlines some of the events in the process of photosynthesis in a chloroplast. water site 1 light dependent stage B C A site 2 D light ind...
Farmers can use insecticides to remove parasites from their sheep. Some of these insecticides act as inhibitors of the enzyme acetylcholinesterase.
Seaweeds are photosynthetic multicellular organisms found on the coast of many parts of the world. There are green, brown and red seaweeds. During ...
Parkinson's disease occurs when nerve cells in part of the brain die, resulting in less secretion of a neurotransmitter called dopamine. Dopamine i...
The photomicrograph shows onion cells. [Photomicrograph of onion cells with label Y] The actual length of the onion cell labelled Y is 350 µm. W...
Which row correctly shows the presence of a cell structure in typical plant cells and in typical prokaryotic cells?
Which letter identifies cell structures where semi-conservative replication of DNA occurs? [Venn diagram showing chloroplasts, mitochondria, nucle...
Which parts of a cell contain ribosomes? 1 chloroplast 2 mitochondrion 3 Golgi body 4 cytoplasm
Which range of cell diameters is typical for prokaryotic cells?
Which row shows a combination of molecules that could be found together in a single isolated virus?
A student carried out four biochemical tests on a sample of food. test: emulsion, observation: cloudy test: Benedict's, observation: yellow test: ...
Which diagram represents a molecule of α-glucose?
Which statements about glycosidic bonds are correct? 1 Condensation between glucose and fructose uses water and forms sucrose. 2 Glycogen contains...
A triglyceride has ......1..... bonds formed by joining fatty acids to .2....... Which row correctly completes this sentence?
The diagram shows a phospholipid molecule divided into three regions, X, Y and Z. R, in region X, represents a range of possible chemical groups. ...
Which statement about collagen is correct?
Catechol is a chemical found in a number of fruits. Catechol can be oxidised to a quinone by the enzyme catechol oxidase. Catechol oxidase is inhi...
Which statements about the fluid mosaic model of a membrane are correct? 1 The movement of phospholipids in the membrane is reduced if the fatty a...
Diagram 1 and diagram 2 show how the transverse section through a leaf changes when the leaf is moved from solution X to solution Y. [Diagram 1 an...
Which features must always be present for water to move between two solutions by osmosis? 1 carrier proteins 2 cell surface membrane 3 selectively...
When living pancreatic cells were placed in a solution of a red stain called neutral red, the cytoplasm became red. The cells were then removed fro...
DNA molecules in a eukaryotic cell must be packaged compactly because their combined length is much greater than the diameter of the nucleus. Whic...
Which statements about mitosis are correct? 1 Mitosis results in genetically identical cells. 2 Mitosis is involved in asexual reproduction. 3 Mit...
A human chromosome is made up of different parts. Some parts of a typical human chromosome are more numerous than others. Which parts are listed i...
A piece of double-stranded DNA containing 12 × 10³ nucleotides is transcribed and translated to produce a single polypeptide. What is the maximum ...
Which statements about complementary base pairing are correct? 1 Cytosine forms two hydrogen bonds with guanine. 2 Purines and pyrimidines are dif...
What are the products when a DNA molecule replicates?
Which descriptions apply to phloem sieve tube elements and to xylem vessel elements? 1 no cytoplasm 2 no end walls 3 no nucleus
Some of the parts of a plant root involved in water transport are listed. 1 Casparian strip 2 cell walls of cortex cells 3 endodermal cells 4 epid...
What is an example of a mass flow system in a plant?
The diameter of a tree trunk usually decreases slightly during the day. Which changes in environmental factors during the day could cause the diam...
Which statement about the role of co-transporter proteins in the movement of sucrose is correct?
Which row correctly describes the heart during atrial systole?
The diagram shows a capillary, some tissue cells and a lymph vessel. [Diagram showing capillary, tissue cells, lymph vessel and arrows labeled 1, ...