GCE A/L Bio Systems Technology key terms

A set of working practices that keep cultures and sterile materials free from contaminating microorganisms, including flaming loops, working near a flame, and never opening a sterile container unnecessarily.

A sealed pressure vessel that sterilises equipment and media using saturated steam above atmospheric pressure, typically reaching 121 degrees Celsius for 15 to 20 minutes to kill endospores.

A ventilated enclosure with filtered airflow that protects the worker, the sample, or both from aerosols and contamination, classified by levels such as Class I, II and III.

A cell lacking a membrane-bound nucleus and membrane-bound organelles, with genetic material held in a nucleoid region, as found in bacteria and archaea.

A cell whose DNA is enclosed within a nuclear envelope and which contains membrane-bound organelles such as mitochondria, endoplasmic reticulum and Golgi apparatus.

A specialised structure inside a eukaryotic cell, often membrane-bound, that performs a distinct function such as energy release, protein synthesis or waste breakdown.

A double-membraned organelle in eukaryotic cells where aerobic respiration and oxidative phosphorylation occur, generating most of the cell's ATP supply.

The smallest distance between two points at which they can still be distinguished as separate objects, determined mainly by the wavelength of light and the numerical aperture of the lens.

The factor by which an image is enlarged compared with the actual specimen, calculated by multiplying the objective lens power by the eyepiece power.

A dimensionless number describing a lens's ability to gather light, derived from the refractive index of the medium and the angle of light acceptance; higher values give better resolution.

A transparent oil with a refractive index close to glass that is placed between the specimen slide and objective lens to increase numerical aperture and improve resolution at high power.

A differential staining method that divides bacteria into Gram-positive and Gram-negative groups according to whether their thick peptidoglycan wall retains the crystal violet-iodine complex after alcohol decolourisation.

A population of microorganisms derived from a single species or strain, grown in the absence of other organisms, so that its properties can be studied reliably.

A technique in which an inoculating loop is drawn across an agar surface in successive sectors to dilute the sample and yield separated colonies, each arising from one cell.

A measure of viable microbial numbers, counting visible colonies that each develop from one cell or a clump of cells, expressed per millilitre or per gram of sample.

A stepwise dilution of a sample in a fixed ratio to produce a range of concentrations, often used to obtain countable colony numbers or to prepare standards for assays.

An undifferentiated mass of dividing plant cells produced on a nutrient medium containing auxin and cytokinin, used as starting material for regeneration or cell suspension cultures.

A small piece of living tissue or organ removed from a donor plant or animal and placed on a culture medium to initiate growth in vitro.

The development of embryos from somatic cells, bypassing fertilisation, so that complete plantlets can be regenerated from cultured tissue such as callus.

The rapid clonal multiplication of plants in vitro from small explants under sterile conditions, producing many genetically identical plantlets from one parent.

The transfer of cells or tissue to fresh nutrient medium to maintain growth, relieve nutrient depletion and dilute toxic metabolic products that accumulate over time.

A biological catalyst, usually a globular protein, that speeds up a specific reaction by lowering activation energy without being consumed in the process.

The region of an enzyme where substrate molecules bind and the chemical reaction is catalysed, with a shape and chemistry complementary to the substrate.

Loss of an enzyme's three-dimensional shape and activity caused by heat, extremes of pH or chemicals that break the bonds maintaining the protein's structure.

A reversible reduction in enzyme activity in which a molecule resembling the substrate binds the active site and competes with the true substrate, an effect relieved by raising substrate concentration.

A metabolic process in which microorganisms convert organic substrates, often sugars, into products such as ethanol, organic acids or gases, used industrially in bioreactors.

An enzyme attached to or entrapped within a solid support so that it can be reused and easily separated from product, improving stability and process economics.

A controlled vessel in which living cells or enzymes carry out a desired reaction, with monitored temperature, pH, aeration and mixing to optimise yield.

One of two or more alternative versions of a gene at the same locus on a chromosome, which may differ in DNA sequence and produce different traits.

The particular combination of alleles present in an organism for a given gene or set of genes, which interacts with the environment to produce the observable phenotype.

A bacterial enzyme that cuts DNA at a specific recognition sequence, producing fragments with sticky or blunt ends used in cloning and DNA analysis.

A small, circular extrachromosomal DNA molecule that replicates independently in bacteria and is widely used as a vector to carry inserted genes into host cells.

The joining of two DNA molecules by forming phosphodiester bonds between their ends, typically catalysed by DNA ligase after restriction digestion.

An in vitro technique that copies a target DNA sequence through repeated cycles of denaturation, primer annealing and extension, giving exponential amplification.

A method that separates charged molecules such as DNA fragments by size as they migrate through a gel under an electric field.

Any molecule, often foreign, that can be specifically recognised and bound by an antibody or T-cell receptor and can provoke an immune response.

An antibody produced by a single clone of cells, identical in specificity and binding to one epitope, widely used in diagnostics and therapy.

An enzyme-linked immunosorbent assay that detects antigens or antibodies by an enzyme label producing a colour change measured with a plate reader.

A dormant, highly resistant structure formed inside certain bacteria, particularly Bacillus and Clostridium, that survives heat, desiccation and disinfectants.

Any biological agent or material that poses a risk to human health or the environment, requiring containment, labelling and safe disposal procedures.

Wearable items such as gloves, goggles, masks and lab coats that form a barrier between the worker and hazardous biological or chemical agents.

The voluntary agreement of a person to participate in research or treatment after receiving and understanding full information about risks, benefits and alternatives.

The principles and practices used to prevent unintentional exposure to biological agents or their accidental release, organised into containment levels.

The study of moral questions raised by biotechnology, including consent, genetic modification, ownership of biological material, and equitable access to new treatments.

A quality system of management and organisational procedures ensuring that laboratory studies are planned, performed, recorded and reported to consistent, auditable standards.

A written, approved set of step-by-step instructions describing how to perform a routine laboratory task consistently and safely.

The planned and systematic activities, including checks, audits and documentation, that provide confidence that a product or result meets defined quality requirements.