Edexcel GCSE Biology Key Terms

A specialised vacuole located at the front tip of a sperm cell that contains digestive enzymes to break down the egg's protective layers.

The minimum energy required for a reaction to occur; enzymes lower this to speed up reactions.

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

The movement of particles from a region of lower concentration to a region of higher concentration (against a concentration gradient) using energy from respiration.

The chemical process in cells that uses oxygen to break down glucose, releasing energy in the form of ATP.

A carbohydrase enzyme that breaks down starch into the simple sugar maltose.

The ability of a bacterium to survive exposure to antibiotics, often conferred by genes carried on plasmid DNA.

Adenosine triphosphate; the specific energy-carrying molecule produced by respiration and used for cellular processes like active transport.

A blue chemical reagent used to test for reducing sugars, which changes colour when heated with a positive sample.

A type of asexual reproduction used by bacteria where the cell divides into two identical daughter cells after replicating its DNA.

Substances produced by living organisms that increase the rate of specific chemical reactions without being consumed or permanently changed.

A scientific representation that records exactly what is observed under a microscope, using specific conventions like clear continuous lines and no shading.

A mixture of potassium hydroxide and copper (II) sulfate that turns from blue to purple in the presence of proteins.

A chemical test used to identify the presence of proteins by detecting peptide bonds.

A highly accurate, sealed piece of equipment used to measure the energy content of food by burning it in pure oxygen to ensure complete combustion with minimal heat loss.

The process of splitting large, insoluble molecules into smaller, soluble molecules for absorption into the bloodstream.

A solution used to maintain a constant, specific pH throughout an experiment by resisting changes in acidity or alkalinity.

Special liquids used in experiments to maintain a specific, constant pH level.

The experimental process of measuring the amount of energy contained in a substance (food) by burning it and measuring the temperature increase of a known volume of water.

A specialized protein in the cell membrane that uses energy to change shape and move specific substances across the membrane against their gradient.

A partially permeable barrier that controls the movement of substances into and out of the cell.

A liquid solution of water, dissolved sugars, mineral ions, and salts found inside the permanent vacuole of a plant cell.

A complex carbohydrate that makes up the plant cell wall, providing it with high tensile strength.

A rigid outer layer that provides structural support; made of cellulose in plants and peptidoglycan in bacteria.

The internal forces (specifically hydrogen and ionic bonds) that hold the 3D structure of an enzyme together.

The energy stored in the chemical bonds of organic molecules, such as carbohydrates, lipids, and proteins, found in food.

A green pigment found in chloroplasts that absorbs light energy for photosynthesis.

Sub-cellular structures in plant and algal cells that contain chlorophyll and are the site of photosynthesis.

A single, long, circular loop of DNA found free-floating in the cytoplasm of bacteria, carrying essential genetic information.

Linear structures made of DNA, found in the nucleus of eukaryotic cells, which carry genetic information.