Related topics: genes · protein · cells · genome · chromosomes

Scientists unwind mystery behind DNA replication

The molecules of life are twisted. But how those familiar strands in DNA's double helix manage to replicate without being tangled up has been hard to decipher. A new perspective from Cornell physicists is helping unravel ...

Researchers map the evolutionary history of oaks

How oaks are related has long posed a challenge to scientists. Dr. Andrew Hipp, senior scientist at The Morton Arboretum, led an international team of 24 scientists to unravel the history of global oak diversity for the first ...

Buttons and flies help biologists solve longtime DNA mystery

Biologists at Johns Hopkins University have uncovered an important clue in the longtime mystery of how long strands of DNA fold up to squeeze into microscopic cells, with each pair of chromosomes aligned to ensure perfect ...

10,000 types of plant outgrowths bundled

For nine years he worked on the three-volume standard work Plant Galls of Europe. It yielded 2300 pages about 10,000 species of European galls, abnormal outgrowths in plants caused by parasites. Hans Roskam from the Institute ...

DNA metabarcoding useful for analyzing human diet

A new study demonstrates that DNA metabarcoding provides a promising new method for tracking human plant intake, suggesting that similar approaches could be used to characterize the animal and fungal components of human diets. ...

The cholera bacterium can steal up to 150 genes in one go

EPFL scientists have discovered that predatory bacteria like the cholera pathogen can steal up to 150 genes in one go from their neighbors. The study sheds light on one of the most fundamental mechanisms of horizontal gene ...

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DNA

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules. The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the use of this genetic information.

Chemically, DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups joined by ester bonds. These two strands run in opposite directions to each other and are therefore anti-parallel. Attached to each sugar is one of four types of molecules called bases. It is the sequence of these four bases along the backbone that encodes information. This information is read using the genetic code, which specifies the sequence of the amino acids within proteins. The code is read by copying stretches of DNA into the related nucleic acid RNA, in a process called transcription.

Within cells, DNA is organized into X-shaped structures called chromosomes. These chromosomes are duplicated before cells divide, in a process called DNA replication. Eukaryotic organisms (animals, plants, fungi, and protists) store most of their DNA inside the cell nucleus and some of their DNA in the mitochondria (animals and plants) and chloroplasts (plants only). Prokaryotes (bacteria and archaea) however, store their DNA in the cell's cytoplasm. Within the chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed.

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