Category Archives: DNA

DNA Structure and Function Background History: Mitosis in onion root tip DNA stands for deoxyribonucleic acid. DNA is pretty unusual in that it is about the only common molecule capable of directing its own synthesis. The processes of mitosis and meiosis were discovered in the 1870s and 1890s. It was observed that, as cells divided, chromosomes moved around in a cell, and people began to wonder what their function was. It was determined that chromosomes were made of protein and DNA, about which people knew almost nothing. People began to suspect that chromosomes had something to do with genetics, but couldnt explain what/how. When enough evidence was accumulated to confirm that chromosomes did, indeed, have something to do with genetics, most people thought that in some way the protein in the chromosomes served as the genetic material. People knew that DNA was also in the chromosomes, but because its structure was unknown and people didnt know much about it, few people thought it was the genetic material. Griffiths Experiment In 1928, Frederick Griffith performed an experiment using pneumonia bacteria and mice. This was one of the first experiments that hinted that DNA was the genetic code material. Click on the … Continue reading →

Within the nucleus of every cell are long strings of DNA, the code that holds all the information needed to make and control every cell within a living organism. DNA, which stands for deoxyribonucleic acid, resembles a long, spiraling ladder. It consists of just a few kinds of atoms: carbon, hydrogen, oxygen, nitrogen, and phosphorus. Combinations of these atoms form the sugar-phosphate backbone of the DNA -- the sides of the ladder, in other words. Other combinations of the atoms form the four bases: thymine (T), adenine (A), cytosine (C), and guanine (G). These bases are the rungs of the DNA ladder. (It takes two bases to form a rung -- one for each side of the ladder.) A sugar molecule, a base, and a phosphate molecule group together to make up a nucleotide. Nucleotides are abundant in the cell's nucleus. Nucleotides are the units which, when linked sugar to phosphate, make up one side of a DNA ladder. During DNA replication, special enzymes move up along the DNA ladder, unzipping the molecule as it moves along. New nucleotides move in to each side of the unzipped ladder. The bases on these nucleotides are very particular about what they connect … Continue reading →

Despite what you may have seen in some textbooks, DNA is not built like a twisted ladder. The helix, or spiral, is an inherent feature of the DNA molecule. Notice, for instance, that in the picture below, that the groove on the left side of the picture is much larger than the right side. This is because the paired bases in the center meet each other at an angle. DNA is a very large molecule; the image here shows only a tiny fraction of the typical molecule. If an entire molecule of DNA from the virus "bacteriophage lambda" were shown at this scale, the image would be 970 meters high. For the bacterium Escherichia coli, the image would be 80 kilometers long. And for a typical piece of DNA from a eukaryote cell, the image would stretch for 1600 kilometers, about as far as it is from Dallas to Washington, D. C.! Obviously such a large molecule is not fully stretched out inside the cell, but is wound around proteins called histones which protect the DNA. Read the original: DNA Helix - University of California Museum of Paleontology … Continue reading →

Why Choose DDC? DNA Diagnostics Center (DDC) is proud to offer the most convenient DNA paternity testing locations in Philadelphia and surrounding areas. DDC is the world's most trusted DNA paternity testing laboratory. Since 1995 we have offered the highest quality DNA testing at affordable prices. Schedule your appointment today by calling one of our consultants at 1-800-613-5768 - we'll arrange sample collection at a location most convenient for you. Fast Results: Online Access in 1 Day #1 Recommended: By Hospitals and TV 100% Accuracy: Legal Samples Tested 2X Free Consultation: 1-800-613-5768 DDC is an AABB accredited laboratory that can coordinate all DNA sample collections regardless of location. For immigration testing, there are guidelines issued by the US Department of State and AABB that require an AABB laboratory to coordinate the entire DNA testing process. >Go to Immigration Page Enter your ZIP code to find a collection location close to your home or work: DDC offers a variety of DNA Paternity Testing options for every situation: Legal: Legally Admissible Results Home Strictly for Peace of Mind Prenatal: Non-Invasive Testing Available Read the original here: Philadelphia DNA Testing Services | Paternity Tests … Continue reading →

Father's Day is June 21. Give the gift of knowledge. Order now. Receive in time for Father's Day order by 03/00 12pm. Select Express Shipping at checkout. Find out how these two women discovered their connection as sisters. See all stories Find out what percent of your DNA comes from populations around the world, ranging from East Asia, Sub-Saharan Africa, Europe, and more. Break European ancestry down into distinct regions such as the British Isles, Scandinavia and Italy. People with mixed ancestry, African Americans, Latinos, and Native Americans will also get a detailed breakdown. What will your Ancestry Composition look like? Your personalized 23andMe web account provides secure and easy access to your information, with multiple levels of encryption and security protocols protecting your personal information. See our Privacy Policy for more information. The Genetic Information Nondiscrimination Act (GINA) is U.S. federal legislation that protects Americans from discrimination (in health insurance and employment decisions) on the basis of genetic information. Click here to learn about how GINA protects your genetic privacy. 23andMe is a DNA analysis service providing information and tools for individuals to learn about and explore their DNA. We use the Illumina HumanOmniExpress-24 format chip (shown here). Our … Continue reading →

DNA,abbreviation of deoxyribonucleic acid, DNAEncyclopdia Britannica, Inc.organic chemical of complex molecular structure that is found in all prokaryotic and eukaryotic cells and in many viruses. DNA codes genetic information for the transmission of inherited traits. A brief treatment of DNA follows. For full treatment, see genetics: DNA and the genetic code. DNA: part of polynucleotide chainEncyclopdia Britannica, Inc.The chemical DNA was first discovered in 1869, but its role in genetic inheritance was not demonstrated until 1943. In 1953 James Watson and Francis Crick determined that the structure of DNA is a double-helix polymer, a spiral consisting of two DNA strands wound around each other. Each strand is composed of a long chain of monomer nucleotides. The nucleotide of DNA consists of a deoxyribose sugar molecule to which is attached a phosphate group and one of four nitrogenous bases: two purines (adenine and guanine) and two pyrimidines (cytosine and thymine). The nucleotides are joined together by covalent bonds between the phosphate of one nucleotide and the sugar of the next, forming a phosphate-sugar backbone from which the nitrogenous bases protrude. One strand is held to another by hydrogen bonds between the bases; the sequencing of this bonding is specifici.e., adenine bonds … Continue reading →

In genomics and related disciplines, noncoding DNA sequences are components of an organism's DNA that do not encode protein sequences. Some noncoding DNA is transcribed into functional non-coding RNA molecules (e.g. transfer RNA, ribosomal RNA, and regulatory RNAs). Other functions of noncoding DNA include the transcriptional and translational regulation of protein-coding sequences, scaffold attachment regions, origins of DNA replication, centromeres and telomeres. The amount of noncoding DNA varies greatly among species. For example, over 98% of the human genome is noncoding,[2] while 20% of a typical prokaryote genome is noncoding.[3] When there is much non-coding DNA, a large proportion appears to have no biological function for the organism, as theoretically predicted in the 1960s. Since that time, this non-functional portion has often been referred to as "junk DNA", a term that has elicited strong responses over the years.[4] The international Encyclopedia of DNA Elements (ENCODE) project uncovered, by direct biochemical approaches, that at least 80% of human genomic DNA has biochemical activity.[5] Though this was not necessarily unexpected due to previous decades of research discovering many functional noncoding regions,[3][6] some scientists criticized the conclusion for conflating biochemical activity with biological function.[7][8][9][10][11] Estimates for the biologically functional fraction of our genome … Continue reading →

1. Genetics. deoxyribonucleic acid: an extremely long macromolecule that is the main component of chromosomes and is the material that transfers genetic characteristics in all life forms, constructed of two nucleotide strands coiled around each other in a ladderlike arrangement with the sidepieces composed of alternating phosphate and deoxyribose units and the rungs composed of the purine and pyrimidine bases adenine, guanine, cytosine, and thymine: the genetic information of DNA is encoded in the sequence of the bases and is transcribed as the strands unwind and replicate. 2. the set of nongenetic traits, qualities, or features that characterize a person or thing: Humility is just not in her DNA. Examples from the web for DNA Expand British Dictionary definitions for DNA Expand Word Origin and History for DNA Expand 1944, abbreviation of deoxyribonucleic acid (1931). DNA in Medicine Expand DNA (d'n-') n. Deoxyribonucleic acid; a nucleic acid that consists of two long chains of nucleotides twisted together into a double helix and joined by hydrogen bonds between complementary bases adenine and thymine or cytosine and guanine; it carries the cell's genetic information and hereditary characteristics via its nucleotides and their sequence and is capable of self-replication and RNA synthesis. DNA … Continue reading →

Hank introduces us to that wondrous molecule deoxyribonucleic acid - also known as DNA - and explains how it replicates itself in our cells. Crash Course Biology is now available on DVD! http://dftba.com/product/1av/CrashCou... Like CrashCourse on Facebook: http://www.facebook.com/YouTubeCrashC... Follow CrashCourse on Twitter: http://www.twitter.com/TheCrashCourse References for this episode can be found in the Google document here: http://dft.ba/-2hCl 1:41 link to Biological Molecules http://www.youtube.com/watch?v=H8WJ2K... Table of Contents: 1) Nucleic Acids 1:30 2) DNA -A) Polymers 1:53 -B) Three Ingredients 2:12 -C) Base Pairs 3:45 -D) Base Sequences 4:13 3) Pop Quiz 5:07 4) RNA 5:36 -A) Three Differences from DNA 5:43 5) Biolography 6:16 6) Replication 8:49 -A) Helicase and Unzipping 9:22 -B) Leading Strand 9:38 -C) DNA Polymerase 10:08 -D) RNA Primase 10:24 -E) Lagging Strand 10:46 -F) Okazaki Fragments 11:07 -F) DNA Ligase 11:47 DNA, deoxyribonucleic acid, chromosome, nucleic acid, ribonucleic acid, RNA, polymer, nucleotide, double helix, nucleotide base, base pair, base sequence, friedrich miescher, rosalind franklin, replication, helicase, leading strand, lagging strand, rna primase, dna polymerase, okazaki fragment Support CrashCourse on Subbable: http://subbable.com/crashcourse Excerpt from: DNA Structure and Replication: Crash Course Biology #10 ... … Continue reading →

DNA is extracted from human cells for a variety of reasons. With a pure sample of DNA you can test a newborn for a genetic disease, analyze forensic evidence, or study a gene involved in cancer. Try this virtual laboratory to perform a cheek swab and extract DNA from human cells. Javascript is required to view this content. Supported by a Science Education Partnership Award (SEPA) Grant No. R25RR016291 from the National Center for Research Resources, a component of the NIH. The contents provided here are solely the responsibility of the authors and do not necessarily represent the official views of NIH. APA format: Genetic Science Learning Center (2014, June 22) DNA Extraction. Learn.Genetics. Retrieved May 22, 2015, from http://learn.genetics.utah.edu/content/labs/extraction/ MLA format: Genetic Science Learning Center. "DNA Extraction." Learn.Genetics 22 May 2015 Chicago format: Genetic Science Learning Center, "DNA Extraction," Learn.Genetics, 22 June 2014, (22 May 2015) Visit link: DNA Extraction - Learn Genetics … Continue reading →