AQA GCSE Biology Cell Biology Definitions PDF

Definitions and Concepts for AQA Biology GCSE Topic 1: Cell Biology Definitions in ​bold ​are for higher tier only Definitions marked by ‘*’ are for separate sciences only Active transport: ​The movement of substances f...

Definitions and Concepts for AQA Biology GCSE Topic 1: Cell Biology Definitions in ​bold ​are for higher tier only Definitions marked by ‘*’ are for separate sciences only Active transport: ​The movement of substances from a more dilute solution to a more concentrated solution (against a concentration gradient) with the use of energy from respiration. Adult stem cell: ​A type of stem cell that can form many types of cells. Agar jelly: ​A substance placed in petri dishes which is used to culture microorganisms on. Cell differentiation: ​The process where a cell becomes specialised to its function. Cell membrane: ​A partially permeable barrier that surrounds the cell. Cell wall: ​An outer layer made of cellulose that strengthens plant cells. Chloroplast: ​An organelle which is the site of photosynthesis. Chromosomes: ​DNA structures that are found in the nucleus which are made up of genes. Concentration gradient: ​The difference in concentration between two areas. Diffusion: ​The spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.✢ Embryonic stem cell: ​A type of stem cell that can differentiate into most types of human cells. Eukaryotic cell: ​A type of cell found in plants and animals that contains a nucleus. Magnification: ​How much bigger an image appears compared to the original object. Meristematic cells: ​A type of stem cell that can differentiate into any type of plant cell. Mitochondria:​ An organelle which is the site of respiration. www.pmt.education Mitosis: ​A type of cell division which produces two genetically identical daughter cells from one parent cell. Nucleus: ​An organelle found in most eukaryotic cells that contains the genetic material of the cell and controls the activities of the cell. Organelle: ​A specialised structure found inside a cell. Osmosis: ​The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane. Plasmid: ​Loops of DNA found in the cytoplasm of prokaryotic cells. Prokaryotic cell: ​A type of cell found in bacteria that does not contain a nucleus. Resolution: ​The ability to distinguish two different points in a specimen. Specialised cells: ​Cells that are adapted to perform a specific function​. Stem cell: ​An undifferentiated cell that can divide to produce many specialised cells of the same type. Surface area: ​The amount of contact an object has with its environment. Surface area to volume ratio (SA:V): ​The size of the object compared with the amount of area where it contacts its environment. The cell cycle: ​A series of stages preparing the cell for division. Therapeutic cloning: ​Producing an embryo that has the same genes as a patient. Vacuole: ​An organelle that stores cell sap. Definitions denoted with a ‘✢’ taken from: ​AQA GCSE Biology Specification, 8461, Version 1.0 2.1, April 2016 www.pmt.education