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.
When organisms reproduce, they pass on their alleles to the next generation. There are many factors that can affect how allele frequencies change o...
Rice, Oryza sativa, is an important grain crop. A rice grain is a seed and can have a structure known as an awn, which projects from the tip of the...
Sexual reproduction in plants and animals involves: the formation of gametes as a result of meiosis the process of fertilisation.
A number of diseases in humans can be treated using recombinant human proteins. These are produced by recombinant DNA technology.
Guard cells are located in the epidermis of the leaves of most plants. When environmental conditions change, this causes changes in guard cells tha...
An axon membrane is described as being at its resting potential when an action potential is not occurring.
A lichen describes a mutually beneficial association of a fungus with an organism termed a photobiont. An example of a photobiont is the green alga...
The biodiversity of an area can be assessed using a variety of sampling methods.
The grey seal, Halichoerus grypus, is an aquatic mammal that lives in the North Atlantic Ocean. It feeds on fish, which it hunts at depths of up to...
Fig. 1.1 is a diagram of part of a liver cell. [Figure 1.1]
Natural selection and selective breeding (artificial selection) are processes that result in changes in the gene pool of a population. Natural sele...
An operon is a section of DNA found in prokaryotes.
The Grand Canyon is located in Arizona, USA. It is estimated to have formed over five million years ago as the Colorado River began to create a dee...
Recombinant DNA technology is used to make recombinant human proteins. Two of the available methods to obtain the gene of interest are: • cutting t...
The kidneys have a role in excretion and in osmoregulation. Excretion is the removal of the waste products of metabolism or the removal of substanc...
A chloroplast is composed of many structures, each with a different function. Several chloroplast structures are listed. stroma lamellae thylakoid ...
The Boelen's python, Simalia boeleni, is a non-venomous snake found only on the island of Papua New Guinea. Fig. 8.1 shows a Boelen's python. [Figu...
Most carnivorous mammals need to move to hunt their prey.
The golden poison dart frog, Phyllobates terribilis, lives in the Colombian rainforest ecosystem. Fig. 10.1 shows golden poison dart frogs. [Figure...
Pepsin is an enzyme that is present in gastric juice. Gastric juice is secreted into the stomach of humans and many other animals. Pepsin catalyses...
Golden orb weaver spiders, Nephila pilipes, are found in East Asia, South-east Asia and Australia. They are active in the day and at night. Golden ...
Phosphatases are enzymes that catalyse the removal of phosphate from other molecules, releasing inorganic phosphate (P₁). A phosphatase can be extr...
Sponges are immobile, aquatic animals that live on rocks and sediment at the bottom of salt water environments. [Figure 2.1] Fig. 2.1 shows an ex...
Drosophila melanogaster is a species of fruit fly. [Figure 1.1] shows a female fruit fly and a male fruit fly. A typical fruit fly is 3 mm in lengt...
Echidnas are mammals that live in Australia and New Guinea. [Figure 2.1] shows an echidna. Scientists analysed the milk produced by female echidnas...
Which cell structure can be seen only with an electron microscope?
Which is a feature of all prokaryotic cells?
A lymphocyte has a diameter of 1 × 10¯² millimetres (mm). What is the diameter in nanometres (nm)?
Which plan diagram of a transverse section of a leaf correctly shows the position of xylem and phloem as well as the fact that the palisade mesophy...
The photomicrograph of a cell has a 2 cm scale line labelled 5 µm. [Photomicrograph of a cell with a 5 µm scale line] What is the magnification of ...
What is a function of the smooth endoplasmic reticulum?
Which combination of bond types correctly shows the weak and strong bonds that hold a molecule of protein in shape?
Which statement is true for cellulose, but not true for protein?
The diagram shows a triglyceride molecule that has been partially hydrolysed. [Diagram of a partially hydrolysed triglyceride molecule] What will b...
The diagram shows a tripeptide molecule. [Diagram of a tripeptide molecule with points 1, 2, 3, 4 indicated] At which two points will hydrolysis oc...
Which combination of procedures would not be used in a food test?
HIV-1 protease is an enzyme produced by the HIV virus. Two identical chains of 99 amino acids form the enzyme. In each chain, amino acids 25, 26 an...
Which features of collagen result in it having high tensile strength? 1 covalent bonds form between adjacent molecules 2 each three-stranded molecu...
The diagram shows a red blood cell and the concentrations of ions, in mmol dm⁻³ in and in the cell. [Diagram of a red blood cell showing ion concen...
Diagrams 1 and 2 show how the transverse section through a leaf changes when one solution W to a different solution Y. [Diagram 1 showing a cell in...
In an experiment, 5 cm³ of 1% salivary amylase are added to 100 cm³ of different concentrations of starch. Which graph shows the results of plottin...
Cystic fibrosis is a disease where Cl¯ ions are unable to be transported into cells. Which structure in the cell surface membrane is faulty? [Diagr...
Cancer cells divide out of control, forming tumours. Which statement describes the difference between a cancer cell and a normal cell?
Which statement describes a cell that is capable of reproduction and belonging to a haploid organism?
During which stage of the mitotic cell cycle is DNA replicated?
The following statements describe events that take place during DNA replication and transcription. Which statement is not correct?
Which diagram shows the semi-conservative replication of a section of a molecule of?
What is the sequence of events in the translocation of assimilates?
Which description states some of the features of xylem vessels?
The diagram shows the changes in pressure potential (Ψp), solute potential (Ψs) and water potential (Ψ) when a plasmolysed plant cell is placed in ...