Nucleic acid structureNucleic acid structure refers to the structure of nucleic acids such as DNA and RNA. Chemically speaking, DNA and RNA are very similar. Nucleic acid structure is often divided into four different levels: primary, secondary, tertiary, and quaternary. Nucleic acid sequence Primary structure consists of a linear sequence of nucleotides that are linked together by phosphodiester bond. It is this linear sequence of nucleotides that make up the primary structure of DNA or RNA.
DNA repairDNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA damage, resulting in tens of thousands of individual molecular lesions per cell per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes.
Homo floresiensisHomo floresiensis (pronflɔːr'ɛzi:ˌɛn.sɪs also known as "Flores Man") is an extinct species of small archaic human that inhabited the island of Flores, Indonesia, until the arrival of modern humans about 50,000 years ago. The remains of an individual who would have stood about in height were discovered in 2003 at Liang Bua cave. Partial skeletons of at least nine individuals have been recovered, including one complete skull, referred to as "LB1".
Homo heidelbergensisHomo heidelbergensis (also H. erectus heidelbergensis, H. sapiens heidelbergensis) is an extinct species or subspecies of archaic human which existed during the Middle Pleistocene. It was subsumed as a subspecies of H. erectus in 1950 as H. e. heidelbergensis, but towards the end of the century, it was more widely classified as its own species. It is debated whether or not to constrain H.
DenisovanThe Denisovans or Denisova hominins (prondɪˈniːsəvə ) are an extinct species or subspecies of archaic human that ranged across Asia during the Lower and Middle Paleolithic. Denisovans are known from few physical remains; consequently, most of what is known about them comes from DNA evidence. No formal species name has been established pending more complete fossil material. The first identification of a Denisovan individual occurred in 2010, based on mitochondrial DNA (mtDNA) extracted from a juvenile female finger bone excavated from the Siberian Denisova Cave in the Altai Mountains in 2008.
