Glossary - Lichens, inconspicuous masterpieces

Symbiosis: A close cooperation between different species that have become dependant on each other and live together.

Mutualism: A symbiotic relationship between two species in which both species benefit from each other.

Cyanobacteria: A phylum of bacteria well known for its ability to photosynthesise. Named after the colour that organisms within the phylum generally have.

Commensal: A symbiotic relationship between two species in which one of the species benefits and the other experiences neither a positive nor a negative effect.

Primary metabolites: All metabolic compounds that are directly involved with growth, maintenance, development and reproduction. Everything that living cells need to survive.

Genes: Stretches of DNA coding for proteins or RNAs as final products. Basic hereditary units of life.

Ribosomal RNA: Important part of ribosomes, the cellular machines that translate the primary products of genes, RNA, into protein. The genes encoding this type of RNA have largely remained the same throughout evolutionary history because of their importance in the synthesis of proteins, the basic workhorses of the cell. Because of this, it offers a good estimation of relatedness between organisms.

Sequence: In biology, a DNA sequence is the order of the building blocks of DNA, called nucleotides, i.e. a string of A, G, T and C. It might also refer to the amino acid sequence of proteins. The order of these building blocks is very important for the function of DNA and proteins and comparison can yield insights into relatedness or function.

Phylum: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain,Kingdom, Phylum, Class, Order,Family, Genus, Species.

Phylogenetic: To do with phylogeny: the study concerned with grouping organisms into evolutionarily related groups, often based upon genome sequences.

Monophyletic group: Group or taxon that includes all the named descendants of a particular most recent common ancestor. That is to say, if five finches all evolved from one primal finch, the five finches are in a monophyletic group.

Fixate: In the context of living organisms this means: 'Incorporate into organic compounds'.

Taxon: Term used to refer to a particular group of organisms. Can be used to refer to: Domain, Kingdom, Phylum, Class, Order, Family, Genus or anything in between.

Reactive oxygen species (ROS): Chemically reactive molecules that contain oxygen. ROS are a natural by-product of oxygen reactions. ROS levels can increase during times of environmental stress, which can cause significant damage to cells.

Denature: In the case of proteins this means: 'lose natural form', and therefore the loss of normal functionality.

Turgid: Inflated by the power of osmosis, a force that strives to balance out the concentrations of solutions divided by a barrier that only allows water to pass, such as a cellular membrane. A cell with strong cell walls, however, is limited in the amount of water it can take up and as a result becomes strongly inflated only up to the point that the wall allows, which gives plants and fungi their rigidness.

Eukaryotic: Concerning eukaryotes: organisms with a nucleus in their cell(s), which sets them apart from prokaryotes, organisms with no nucleus in their cell, i.e. bacteria and the less well known Archaea.

Apoptosis: Controlled cell death, i.e. an orderly recycling of a cell that has outlived its use or is not viable anymore.

Genus: A taxonomic rank in biological classification. The hierarchy of the classification from general to specific is: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Epithelial: Concerning epithelium: tissue that lines the cavities and surfaces of structures throughout the body.

Hepatocytes: Cells that make up most of the liver, from Greek 'ἡπατος' or hepatos, meaning liver.

Homogenised: Blended, mixed until a mixture is equally divided

Promoter: The switch of a gene, encoded in the DNA, which determines if a gene will be transcribed or not. One could say that a gene can be turned on or off by using the switch. There is an array of different promoters that are sensitive to specific internal and external signals, which makes the transcription of a gene dependant on the environment.

Plasmid: Self-replicating, circular piece of DNA.

Genome: An organism's total genetic information.