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.
During sperm formation in mammals, part of the structure of each chromosome is replaced with proteins called protamines. This replacement allows th...
The diagram shows the mitotic cell cycle. During which phase do chromosomes condense and become visible? [Figure 21.1]
Which statements correctly describe features of stem cells that are essential for their role in cell replacement and tissue repair? 1 After mitosis...
Which statements are correct for all nucleotides? 1 The nitrogen-containing base is always attached to carbon atom 1 of the pentose. 2 The phosphat...
How many phosphodiester bonds are present in a circular DNA molecule of 2700 base pairs?
Which statements about complementary base pairing are correct? 1 Purines and pyrimidines are different sizes. 2 Complementary base pairing occurs d...
During the mitotic cell cycle, the chromosomal DNA is replicated. The specific points in DNA molecules where replication is occurring are known as ...
Which molecule has its synthesis directly controlled by DNA?
Which statement correctly describes the association between a companion cell and its sieve tube cell?
A maize seedling was grown in soil that contained lanthanum ions labelled with a chemical that fluoresces under ultraviolet light. The diagram repr...
Which description of adhesion and cohesion is correct?
Which conditions are needed to allow the mass flow of sucrose in phloem sieve tubes?
One type of congenital heart defect is where the left and right atria are not completely separated. This is called an atrial septal defect (ASD). A...
Which property of water, related to its role in blood and tissue fluid, is correctly described?
Which statement about tissue fluid formation is correct?
Oxyhaemoglobin, carbaminohaemoglobin, haemoglobinic acid and carbonic anhydrase are found inside red blood cells. How many of these substances will...
Which of these structures typically contain cartilage and cilia? 1 bronchi 2 bronchioles 3 trachea
Which statements about the function of tissues found in the human gas exchange system are correct? 1 Collagen in the bronchi prevents them collapsi...
Antibiotic-resistant strains of Mycobacterium tuberculosis are a major problem when treating TB. A new antibiotic, teixobactin, could be very effec...
Monoclonal antibodies are now being used to treat some human diseases. What explains why monoclonal antibodies are suitable for this purpose? 1 The...
Measles is an infectious disease caused by a virus. The graph shows the number of cases of measles each year in a country before and after a vaccin...
Fig. 1.1 is a diagram representing part of the phospholipid bilayer of a cell surface membrane. [Figure 1.1] Identify the part of a phospholipid mo...
Table 2.1 shows descriptions of three types of white blood cell. Complete Table 2.1 by stating the names of these three types of white blood cell. ...
Fig. 3.1 is a photomicrograph showing part of a transverse section through the root of an iris, Iris germanica. Irises are herbaceous monocotyledon...
Table 4.1 shows a sequence of 12 nucleotides in the template strand of a short length of a DNA molecule, the corresponding primary transcript and t...
The pathogen that causes cholera is a prokaryote.
Fig. 6.1 is a simplified diagram representing a section through the human immunodeficiency virus (HIV) particle that causes HIV/AIDS. The diagram s...
Seeds of many plant species contain an enzyme that is used to hydrolyse sucrose into reducing sugars. This enzyme is essential to provide the reduc...
P1 is a slide of a stained transverse section through a plant leaf. (b) Fig. 2.1 is a photomicrograph of a transverse section through a leaf of a d...
Fig. 1.1 is a diagram of a nephron. [Figure 1.1]
The scientist Gregor Mendel investigated differences in the length of the stem in the pea plant, Pisum sativum. In 1866, he published the results o...
Cystic fibrosis is an autosomal recessive genetic disease. People with cystic fibrosis have a homozygous recessive genotype.
Holstein Friesian cattle are a breed of cattle used by dairy farmers in many countries of the world for the high milk yield of their cows. [Figure ...
Complete the following paragraphs using the most appropriate word or words. The theory of evolution describes a process that can lead to the format...
A respirometer is a piece of apparatus that can be used to measure the rate of respiration of living tissue such as germinating peas. A simple resp...
The light-dependent stage of photosynthesis occurs within chloroplasts. In this stage, electrons are emitted from the chlorophyll a molecules and p...
Approximately 2 × 10⁹ people in the world are currently infected with the bacterial disease tuberculosis (TB) caused by Mycobacterium tuberculosis....
An investigation was carried out to study the effect of different intensities of blue light on the percentage germination of barley seeds. Barley s...
Striated muscle is composed of myofibrils. Myofibrils contain several structural proteins including troponin, tropomyosin, actin and myosin.
Onions are vegetables that are harvested from the plant Allium cepa. In many countries, small onions are used to make pickled onions. Pickled onion...
Drosophila melanogaster is a small fruit fly that is often used in research on genetics. Wild fruit flies normally have dark red eyes due to the pr...
In an electron micrograph, the length of a mitochondrion is measured as 17.1cm. The magnification of the electron micrograph is ×38000. What is the...
There is a theory that mitochondria and chloroplasts were originally free-living prokaryotes. It is thought that millions of years ago these free-l...
Which row correctly describes a function of each cell structure?
Which cell components are present in typical prokaryotic cells?
X-ray analysis of fossilised cells found in rocks in central India dating back 1.6 billion years has revealed several features. 1 The cells are up ...
The electron micrograph shows an organelle found in some cells of many multicellular organisms. [Figure 6.1] Which row shows structures that are ex...
What could take place during a hydrolysis reaction? 1 A glycosidic bond is broken. 2 A molecule of water is produced. 3 A sucrose molecule is split...
Hydroxyproline is synthesised by addition of an –OH group to the R-group of the amino acid proline. Hydroxyproline is a major component of collagen...
Plant cell walls are strengthened by cellulose molecules that are arranged in several layers. Within each layer, the cellulose molecules are arrang...