I-motif DNA I-motif DNA i-motif DNA is a type of deoxyribonucleic acid, discovered in 2018, that is found in the nuclei of human cells. An abbreviation of intercalated motif, the four-strand i-motif is unlike the iconic double helix DNA. I-motifs are four-stranded quadruplex structures formed by cytosine-rich DNA, similar to the G-quadruplex structures that guanine-rich DNA forms. C-rich DNA regions are common in gene regulation portions of the genome. Recently, i-motifs were discovered in human cells and were shown to play a role in cell reproduction. I-motifs have potential applications in nanotechnology and nanomedicine due to their unique pH sensitivity and have
Cell cycle checkpoint Cell cycle checkpoint All living organisms are the products of repeated rounds of cell growth and division. During this process, known as the cell cycle, a cell duplicates its contents and then divides in two. The purpose of the cell cycle is to accurately duplicate each organism's DNA and then divide the cell and its contents evenly between the two resulting cells. In eukaryotes, the cell cycle consists of four main stages: G, during which a cell is metabolically active and continuously grows; S phase, during which DNA replication takes place; G, during which cell growth continues and the cell