Cyanobacteria are ubiquitous environmental bacteria that have important roles in geochemical events, such as the early oxygenation of the atmosphere. Microfossils found in Australia show that more than 3.6 billion years ago, cynobacteria thrived on an Earth that had no oxygen.

The rectum is the concluding part of the large intestine that terminates in the anus. The rectum stores solid waste until it leaves the body through the anus.

Arginine is an α-amino acid. At the level of molecular genetics, in the structure of the messenger ribonucleic acid mRNA, CGU, CGC, CGA, CGG, AGA, and AGG, are the triplets of nucleotide bases or codons that code for arginine during protein synthesis. In mammals, arginine is classified as a semiessential or conditionally essential amino acid, depending on the developmental stage and health status of the individual.

The coelacanth is a living fossil. Unlike any other living animal, coelacanths have a hinged joint in the skull, which allows the front part of the head to be lifted whilst feeding. They also have limb-like, lobed pectoral and pelvic fins and a unique tail consisting of three distinct lobes. They are considered as the connecting link between pisces and amphibia.

Addition of an amino acid occurs at the C-terminus of the peptide and thus translation is said to be amino-to-carboxyl directed.

One main consequence of coextinction that goes beyond biodiversity is mutualism, by loss of food production with a decline in threatened pollinators. Losses of parasites can have negative impacts on humans or the other species.

Q-banding is a fluorescent pattern obtained using quinacrine for staining. The pattern of bands is very similar to that seen in G-banding. They can be recognised by a yellow fluorescence of differing intensity. Most part of the stained DNA is heterochromatin. Quinacrin (atebrin) binds both regions rich in AT and in GC, but only the AT-quinacrin-complex fluoresces.

H2A is important for packaging DNA into chromatin. Since, H2A packages DNA molecules into chromatin, the packaging process will effect gene expression. H2A has been correlated with DNA modification and epigenetics. H2A plays a major role in determining the overall structure of chromatin.

An inducible gene is a gene whose expression is either responsive to environmental change or dependent on the position in the cell cycle.

Vestigial structures are often homologous to structures that are functioning normally in other species. Therefore, vestigial structures can be considered evidence for evolution, the process by which beneficial heritable traits arise in populations over an extended period of time.

Toc1 gene, also known as Timing of CAB Expression 1 gene, is an oscillating gene found in the plants that is known to control the expression of CAB. It has been shown to affect the period of circadian rhythms through its repression of transcription factors. This was found through mutations of toc1 in plants that had shortened period of CAB expression.

Centromere protein C 1 is a centromere autoantigen and a component of the inner kinetochore plate. The protein is required for maintaining proper kinetochore size and a timely transition to anaphase. A putative pseudogene exists on chromosome 12.

Clock, also known as Circadian Locomotor Output Cycles Kaput, is a transcription factor in the circadian pacemaker of mammals. It affects both the persistence and period of circadian rhythms by its interactions with the gene Bmal1.

Long terminal repeats are identical sequences of DNA that repeat hundreds or thousands of times found at either end of retrotransposons or proviral DNA formed by reverse transcription of retroviral RNA. They are used by retro viruses to insert their genetic material into the host genomes.

The first ORF encodes a RNA-binding protein of 500 amino acid lengths that weighs 40 kDA. This protein contains a leucine zipper motif and functions as a chaperone.