34 of the Biology glossary’s terms, each with the part of the syllabus where you first meet it.
The first generation of offspring produced by crossing two parents (the P generation).
The second generation of offspring, produced by crossing F1 individuals with each other or by self-pollination of the F1.
The passive movement of particles down a concentration gradient across a membrane through a channel protein (or with a carrier protein), without the use of energy from ATP.
An organism that respires aerobically when oxygen is present and anaerobically when it is absent, so it can survive with or without oxygen, for example yeast.
Flavin adenine dinucleotide: a hydrogen carrier reduced in the Krebs cycle; reduced FAD passes its electrons to the electron transport chain at a later carrier than reduced NAD.
The rejection of a hypothesis or theory when evidence contradicts a prediction made from it; a scientific idea must be testable in a way that could show it to be false.
A molecule with a carboxyl group at one end of a long hydrocarbon chain; fatty acids combine with glycerol to form triglycerides and phospholipids.
Regulation of a metabolic pathway in which the end product inhibits an enzyme of an early step, usually the first, by binding to its allosteric site.
A capillary whose endothelial cells have pores (fenestrations) that allow especially rapid exchange of water and solutes, as in kidney glomeruli, intestinal villi and endocrine glands.
The fusion of a male gamete with a female gamete to form a diploid zygote.
The haemoglobin of the fetus, with two γ chains instead of β chains; it has a higher affinity for oxygen than adult haemoglobin, so it takes up oxygen from maternal blood at the placenta.
An insoluble protein formed from fibrinogen by thrombin; its fibres make a mesh that traps blood cells to form a clot.
A protein with a long, thin, strand-like shape, usually insoluble in water and with a structural function, such as collagen or keratin.
The circular area of a specimen that is visible through the eyepiece at one time; its diameter decreases as the magnification increases.
The fluid formed in Bowman's capsule by ultrafiltration, containing water, glucose, amino acids, ions and urea at about plasma concentrations but no blood cells or plasma proteins.
The survival and reproductive potential of a genotype, measured by the number of offspring individuals with that genotype contribute to the next generation, relative to others.
Describes a plant cell whose contents no longer press against the cell wall because it has lost water, so that it has no turgor pressure; flaccid tissue is soft and limp.
A long whip-like projection from a cell that moves it through liquid; eukaryote flagella have a microtubule core and are usually one or two per cell, while prokaryote flagella are simpler protein fibres.
Bending movement at a joint that decreases the angle between the two bones, such as bending the knee.
The model of membrane structure in which proteins are embedded in or attached to a fluid phospholipid bilayer, with phospholipids and many proteins free to move sideways.
A dye that absorbs light of one wavelength and emits light of a longer wavelength, so that the structures it binds to glow against a dark background in a fluorescence microscope.
A fluid-filled sac in the ovary containing a developing oocyte surrounded by follicle cells, which secrete oestradiol.
A hormone (FSH) secreted by the anterior pituitary that stimulates the development of follicles in the ovary and their secretion of oestradiol.
A sequence of organisms in which each feeds on the one before it, showing the direction of transfer of energy and biomass from producers to consumers.
A network of interconnected food chains showing all the feeding relationships in a community.
The preserved remains or traces of an organism from the past, such as bones, shells, imprints or structures like stromatolites, usually found in sedimentary rock.
A fuel such as coal, oil or natural gas formed over millions of years from the buried remains of organisms in which decomposition was incomplete.
An insertion or deletion of a number of nucleotides that is not a multiple of three, which changes the reading frame so every codon after the mutation is altered.
The branched, unprotected ending of a sensory neuron in a tissue such as the skin, which detects stimuli such as heat, acid and tissue damage and acts as a pain receptor.
An 80S ribosome in the cytosol that is not attached to a membrane; it synthesises proteins for use within the cytoplasm.
A field experiment (FACE) in which CO₂ is released over a plot of vegetation in the open air to raise its CO₂ concentration while other conditions stay natural.
An electron microscopy technique in which a specimen is frozen rapidly and split so that the fracture runs through the centre of membranes, showing the proteins embedded in them.
The processes carried out by all living organisms: metabolism, nutrition, growth, response to stimuli, movement, excretion, homeostasis and reproduction.
The potential range of conditions and resources in which a species could survive and reproduce, given its adaptations and tolerance limits, in the absence of competition.