Go directly to DNA Workshop Activity (92K - requires Shockwave) An embryonic cell divides again and again. Where there was one cell there are two, then four, then eight,... Each holds all the genetic information needed to create a human being. How, exactly, do these cells make copies of themselves? Hair grows from your head, nonstop, day in and day out. The cells of your hair follicles somehow generate all of the protein that make up this hair. How is this protein created? The answers to these questions are DNA replication and protein synthesis. Knowledge of the structure of DNA began with the discovery of nucleic acids in 1869. That genes control the synthesis of enzymes was understood in the 1940s. In 1953, an accurate model of the DNA molecule was presented, thanks to the work of Rosalind Franklin, James Watson, and Francis Crick. The activity in this section places you within the cell, involving you with the processes of DNA replication and protein synthesis. If you're interested in finding out more about DNA and protein synthesis, check out the other sections. Related People and Discoveries entries Read more: A Science Odyssey: You Try It: DNA Workshop … Continue reading →

Mitochondrial DNA (mtDNA or mDNA)[2] is the DNA located in organelles called mitochondria, structures within eukaryotic cells that convert chemical energy from food into a form that cells can use, adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus, and in plants, the chloroplast as well. In humans, mitochondrial DNA can be assessed as the smallest chromosome coding for 37 genes and containing approximately 16,600 base pairs. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. In most species, including humans, mtDNA is inherited solely from the mother.[3] The DNA sequence of mtDNA has been determined from a large number of organisms and individuals (including some organisms that are extinct), and the comparison of those DNA sequences represents a mainstay of phylogenetics, in that it allows biologists to elucidate the evolutionary relationships among species. It also permits an examination of the relatedness of populations, and so has become important in anthropology and field biology[clarification needed]. Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derived from the circular … Continue reading →

Origem: Wikipdia, a enciclopdia livre. O cido desoxirribonucleico (ADN, em portugus: cido desoxirribonucleico; ou DNA, em ingls: deoxyribonucleic acid) um composto orgnico cujas molculas contm as instrues genticas que coordenam o desenvolvimento e funcionamento de todos os seres vivos e alguns vrus, e que transmitem as caractersticas hereditrias de cada ser vivo. O seu principal papel armazenar as informaes necessrias para a construo das protenas e ARNs. Os segmentos de ADN que contm a informao gentica so denominados genes. O restante da sequncia de ADN tem importncia estrutural ou est envolvido na regulao do uso da informao gentica. A estrutura da molcula de ADN foi descoberta conjuntamente pelo norte-americano James Watson e pelo britnico Francis Crick em 7 de Maro de 1953, o que lhes valeu o Prmio Nobel de Fisiologia ou Medicina em 1962, juntamente com Maurice Wilkins. Do ponto de vista qumico, o ADN um longo polmero de unidades simples (monmeros) de nucleotdeos, cuja cadeia principal formada por molculas de acares e fosfato intercalados unidos por ligaes fosfodister. Ligada molcula de acar est uma de quatro bases nitrogenadas. A sequncia de bases ao longo da molcula de ADN constitui a informao gentica. A leitura destas sequncias feita atravs … Continue reading →

Tuesday, April 22, 2014 IT&E records corroborate testimony about Crisostomo using Kintaro cell phone A Federal Bureau of Investigation forensic examiner in the nuclear DNA unit at the FBI Lab in Quantico, Virginia, testified yesterday that Joseph A. Crisostomos DNA matched the DNA obtained from swab samples taken from the vagina of murdered bartender Emerita R. Romero. Testifying for the CNMI government in the ongoing jury trial of 40-year-old Crisostomo in Superior Court, FBI forensic examiner Susannah Kehl disclosed that she tested the sexual assault kit that the FBI Saipan Office sent to their laboratory and that she concluded the positive presence of semen in Romeros vagina. James Calderwood, IT&E manager for network services, also took the witness stand yesterday about records of cell phone calls from the numbers of Romero and Alicia Kintaro. Kintaro testified last week that Crisostomo borrowed her cell phone in the early morning of Feb. 5, 2012. IT&E records revealed that when Kintaros cell phone was used, the originating cell tower for the call was at Palms Resort in San Roque. Palms Resort is located across the former La Fiesta Mall where Romeros body was found by FBI agents on Feb. 7, 2012. In her … Continue reading →

PUBLIC RELEASE DATE: 21-Apr-2014 Contact: Anita Srikameswaran srikamav@upmc.edu 412-578-9193 University of Pittsburgh Schools of the Health Sciences PITTSBURGH, April 21, 2014 Malfunctions in the molecular "proofreading" machinery, which repairs structural errors in DNA caused by ultraviolet (UV) light damage, help explain why people who have the disease xeroderma pigmentosum (XP) are at an extremely high risk for developing skin cancer, according to researchers at the University of Pittsburgh School of Medicine and the University of Pittsburgh Cancer Institute (UPCI). Their findings will be published this week in the early online version of the Proceedings of the National Academy of Sciences. Previous research has shown that a DNA-repair protein called human UV-damaged DNA-binding protein, or UV-DDB, signals for a repair when two UV-DDB molecules bind to the site of the problem, said senior investigator Bennett Van Houten, Ph.D., the Richard M. Cyert Professor of Molecular Oncology, Pitt School of Medicine, and co-leader of UPCI's Molecular and Cell Biology Program. "Our new study shows UV-DDB makes stops along the DNA strand and transiently attaches to it, causing a proofreading change in the protein's conformation, or shape. If the DNA is damaged the protein stays, if the DNA is not damaged the protein … Continue reading →