GCE A/L Bio Systems Technology flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Bio systems technology

Application of engineering and biological principles to living systems or their components to produce useful products, processes and services across health, agriculture and industry.

Biosafety level 2

Containment level for moderate-risk agents causing human disease; requires restricted access, autoclave on site, biological safety cabinet for aerosol-generating work and trained staff.

Autoclave principle

Moist heat under pressure at 121 degrees Celsius and 15 psi for 15 to 20 minutes denatures microbial proteins and destroys spores, including resistant bacterial endospores.

Fluid mosaic model

Description of the plasma membrane as a phospholipid bilayer with embedded integral proteins, peripheral proteins and cholesterol, giving a dynamic and selectively permeable structure.

Osmosis

Net movement of water across a selectively permeable membrane from a region of lower solute concentration to higher solute concentration until equilibrium is reached.

Apoptosis

Programmed cell death controlled by caspases, producing cell shrinkage, membrane blebbing and apoptotic bodies without inflammation, unlike necrotic cell death.

Resolution formula

d equals 0.61 times wavelength divided by numerical aperture; smaller d means better resolution, achieved by shorter wavelength and higher numerical aperture.

Beer-Lambert law

Absorbance equals molar extinction coefficient times path length times concentration; used in spectrophotometry to quantify solutes such as nucleic acids and bacterial cells.

SDS-PAGE

Electrophoresis of proteins denatured by sodium dodecyl sulfate, which confers uniform negative charge so separation depends mainly on molecular mass.

Bacterial growth curve

Plot of cell number against time showing lag, exponential, stationary and death phases, reflecting nutrient depletion and accumulation of toxic metabolic products.

Chemostat

Continuous culture device maintaining steady exponential growth by feeding fresh medium at a set dilution rate while removing culture at the same rate.

Selective medium

Culture medium containing agents that suppress unwanted microorganisms while allowing the target organism to grow, such as antibiotics or specific salts.

Murashige and Skoog medium

Widely used plant tissue culture medium providing macroelements, microelements, iron-EDTA, vitamins, sucrose and agar for callus and shoot regeneration.

Totipotency

Capacity of a plant cell to dedifferentiate and regenerate a complete fertile plant under suitable culture conditions, the basis of micropropagation.

Michaelis constant Km

Substrate concentration at which reaction velocity is half the maximum; a low Km indicates high enzyme affinity for the substrate.

Competitive inhibition

Inhibitor resembles substrate and binds the active site reversibly, raising apparent Km while maximum velocity remains unchanged at saturating substrate.

Immobilised enzyme

Enzyme fixed to a solid support by adsorption, covalent binding, entrapment or cross-linking, allowing reuse and continuous operation in bioreactors.

Fed-batch fermentation

Culture in which nutrients are added incrementally without removal of broth, avoiding substrate inhibition and prolonging production of secondary metabolites.

Mendel segregation law

Two alleles of a gene separate during gamete formation so each gamete carries one allele, producing predictable offspring ratios in crosses.

Hardy-Weinberg equilibrium

Allele and genotype frequencies remain constant in a large randomly mating population without mutation, migration, selection or genetic drift.

Polymerase chain reaction

In vitro amplification of DNA using denaturation, primer annealing and extension cycles with a thermostable polymerase, doubling target copies each cycle.

Restriction endonuclease

Enzyme recognising a specific palindromic DNA sequence and cutting it, often producing sticky ends used in cloning and gene mapping.

CRISPR-Cas9

Genome editing system in which a guide RNA directs Cas9 nuclease to a target sequence to create a double-strand break repaired by cellular mechanisms.

Monoclonal antibody

Uniform antibody secreted by a hybridoma clone, binding a single specific epitope and used in diagnostics, research and targeted therapy.

ELISA

Immunoassay using an enzyme-linked antibody that converts substrate to a coloured product, enabling sensitive detection of antigens or antibodies.

Biofertiliser

Preparation of living microorganisms such as Rhizobium or mycorrhizae that improves plant nutrient uptake and soil fertility when applied to crops or seeds.

HACCP

Hazard analysis critical control point system identifying biological, chemical and physical hazards and setting control limits at critical points in food production.

Activated sludge process

Aerobic secondary wastewater treatment in which microorganisms oxidise organic matter in an aerated tank, followed by sedimentation of the sludge.

Biogas composition

Gas from anaerobic digestion containing roughly 50 to 70 percent methane and 30 to 50 percent carbon dioxide, used as a renewable fuel.

Biological oxygen demand

Mass of dissolved oxygen consumed by microorganisms oxidising organic matter in a water sample, usually measured over five days at 20 degrees Celsius.

Informed consent

Voluntary agreement by a competent person after full disclosure of purpose, procedures, risks, benefits and right to withdraw from research or treatment.

Three Rs principle

Ethical framework for animal research requiring replacement of animals where possible, reduction in numbers used and refinement of procedures to minimise suffering.