「Purine base」に関連した動画の一覧 |
 | Purine Base - SciencePrimer video glossary More at: www.scienceprimer.com and www.scienceprimer.com A purine base is a nitrogenous base that has a double ring structure made up of a five-atom ring attached by one side to a six-atom ring. The two rings contain a total of five carbon and four nitrogen atoms. Biologically significant purines include the bases adenine and guanine. When bound to a ribose or deoxyribose sugar and a phosphate molecule, these bases form two of the five nucleotide building blocks of DNA and RNA 2012年03月15日再生回数 23 |
 | DNA Structure "Two DNA strands intertwine to form a double helix. Each strand has a backbone composed of phosphates and sugars to which the bases are attached. The bases form the core of the double helix, while the sugar/phosphate backbones are on the outside. The two grooves between the backbones are called the major and minor groove based on their sizes. Most proteinDNA contacts are made in the major grove, because the minor groove is too narrow. The DNA backbone is assembled from repeating deoxyribose sugar units that are linked through phosphate groups. Each phosphate carries a negative charge, making the entire DNA backbone highly charged and polar. A cyclic base is attached to each sugar. The bases are planar and extend out perpendicular to the path of the backbone. Pyrimidine bases are composed of one ring and purine bases of two rings. Adjacent bases are aligned so that their planar rings stack on top of one another. Base stacking contributes significantly to the stability of the double helix. In a double helix, each base on one strand is paired to a base on the other strand that lies in the same plane. In these base pairing interactions, guanine always pairs with cytosine, and thymine with adenine. A GC pair is stabilized by three hydrogen bonds formed between amino and carbonyl groups that project from the bases. In contrast, an AT pair is stabilized by two hydrogen bonds. The specificity of base pairing—that is, C always pairing with G, and A always pairing with T—ensures ... 2009年04月15日再生回数 72992 |
 | PHYSIOLOGY; REVIEW OF NUCLEOTIDES, NUCLEIC ACIDS, VITAMINS & MINERALS by Professor Fink Review of Biological Chemistry, including Nucleotides, Nucleic Acids, Vitamins & Minerals. Reference is made to the components of each nucleotide: a 5-Carbon sugar (ribose or deoxyribose), a nitrogenous base, and phosphate. Purine bases (adenine & guanine) and Pyrimidine bases (thymine, cytosine & uracil) are described. Special reference is made to the high energy nucleotide, Adenosine Triphosphate (ATP), as well as AMP and ADP. Both the molecular structure of RNA is presented, and the molecular structure of DNA. Reference is made to complementary binding of bases and the Double Helix structure of the DNA. Clarification is given to the terms: Chromatids, Chromatin (uncoiled) Shape & Chromosomes (coiled-up) Shape of the DNA molecule. The principal functions of the lipid-soluble vitamins (retinol, calciferol, tocopherol & phylloquinone) & water-soluble vitamins (ascorbic acid, niacin, riboflavin & pantothenic acid) and the macronutrient minerals (calcium, phosphate, sodium & potassium) & micronutrient (trace) minerals (iron, iodine, copper & zinc). Reference is made to anti-oxidants, goiters & anemia. 2012年02月13日再生回数 448 |
 | Arylamines DNA adduct (environmental carcinogens) Arylamines belong to an important class of environmental carcinogens which are implicated in the etiology of many human cancers. 2-Aminofluorene and its derivatives are prototype arylamine carcinogens that form two DNA adducts in vivo: AF and AAF. AF is the major and most persistent adduct. It is known to exist in a sequence-dependent equilibrium between external B-type and stacked S-conformers, as defined by the location (major groove and base-displaced, respectively) of the carcinogen moiety. A minor groove binding wedged (W)-conformer has also been observed in duplexes in which the lesion is mismatched with purine bases. The dynamics of the AF-induced B/S/W-heterogeneity have been shown to be modulated by both the base sequence contexts and the progression for the length of primers, and contribute to polymerase activity through a long-range effect. The sequence effects on adduct conformation and the nature of the polymerase are key factors for determining the mutational outcomes of these important carcinogens. This animation shows the rotating views of the external B-type (B), base-displaced stacked (S), minor groove wedge (W)-conformers. The modified dG and the complementary dC are shown in cyan and green CPK, respectively, and the aminofluorene carcinogen moiety is highlighted with red CPK. Nathan Haskins/Dr. Bongsup Cho 2008年02月05日再生回数 1506 |
 | Bite-Sized Biochemistry #39 - Nucleotide Metabolism I Lecture by Kevin Ahern of Oregon State University discussing Biochemistry Basics in BB 451. See the full course at oregonstate.edu This course can be taken for credit (wherever you live) via OSU's ecampus. For details, see ecampus.oregonstate.edu Download Metabolic Melodies at www.davincipress.com Related courses include BB 350 - oregonstate.edu BB 450 - oregonstate.edu BB 100 - oregonstate.edu Nucleotide Metabolism 1. Nucleotides consist of a) sugar, b) nitrogenous base, and c) phosphate 2. Nucleosides consist of aa) sugar and b) nitrogenous base 3. The sugars of nucleosides and nucleotides are either ribose (found in ribonucleotides of RNA) or deoxyribose (found in deoxyribonucleotides of DNA). 4. The nitrogenous bases found in nucleotides include adenine (purine), guanine (purine), thymine (pyrimidine), cytosine (pyrimidine), and uracil (pyrimidine). 5. The bases adenine, guanine, and cytosine are found in both ribonucleotides and deoxyribonucleotides. Thymine is almost always found in deoxyribonucleotides. Uracil is found primarily in ribonucleotides and rarely in DNA, but does appear as a deoxyribonucleotide intermediate in thymidine metabolism. 6. Ribonucleotides are the building blocks of RNA and deoxyribonucleotides are the building blocks of DNA. 7. Nucleotides and nucleosides are made in cells by two general mechanisms - salvage pathways (use breakdown products of other nucleotides/nucleosides) or de novo pathways (synthesize nucleotides/nucleosides from scratch ... 2011年08月04日再生回数 2556 |
 | #14 BB 350 Membranes III / Nucleic Acids I - Kevin Ahern's Biochemistry Online This video inadvertently had the camera mis-pointed. Kevin Ahern of Oregon State University lecturing to his BB 350 class. See the full course at oregonstate.edu This course can be taken for credit (wherever you live) via OSU's ecampus. For details, see ecampus.oregonstate.edu Topics covered include membrane transport secondary proton gradient concentration arachidonate arachidonic acid prostaglandins leukotrienes thromboxanes nucleic acids DNA RNA bases phosphates sugars ribose deoxyribose adenine guanine cytosine thymine uracil purine pyrimidine double helix complementary Watson Crick base pair GC AT hydrogen bonds 2012年04月26日再生回数 163 |
 | Base Jump Idaho This is some footage from September 05 at Perrine Bridge, Twin Falls Idaho, The only 24/7 legal jumping bridge in the world. 2006年04月04日再生回数 53283 |
 | Purine metabolic pathway This video describes the normal purine metabolic pathway, including the affect on the purine salvage pathway due to a deficiency of the HPRT enzyme in Lesch-Nyhan syndrome patients. Narrated by: Joshua Wiener Adapted from: Johnson & Patel, 1996 2009年12月11日再生回数 12169 |
 | Built-In Error Correction Real Science: Despite the minor variations that exist, the genetic code used by all known forms of life is nearly universal. However, there is a huge number of possible genetic codes. If amino acids are randomly associated with triplet codons, there will be 1.5 x 1084 possible genetic codes.[39]:163 Followed by Science Fiction: Phylogenetic analysis of transfer RNA suggests that tRNA molecules evolved before the present set of aminoacyl-tRNA synthetases.[40] In theory, the genetic code could be completely random (a "frozen accident"), completely non-random (optimal) or a combination of random and nonrandom. There are enough data to refute the first possibility.[41] For a start, a quick view on the table of the genetic code shows a clustering of amino acid assignments. Furthermore, amino acids that share the same biosynthetic pathway tend to have the same first base in their codons,[42] and amino acids with similar physical properties tend to have similar codons.[43][44] There are four themes running through the many theories about the evolution of the genetic code (and hence the origin of these patterns):[45] Proverbs 3:11-12 "My son, despise not the chastening of the LORD; neither be weary of his correction: For whom the LORD loveth he correcteth; even as a father the son in whom he delighteth." It seems like science fiction to suggest that if someone typed your name into a computer, misspelling your name, the computer would find it and correct it. Yet the genetic code ... 2011年11月10日再生回数 288 |
 | Acid-base Properties of Heterocycles II In this webcast, learn about the acid-base properties of some multi-atom heterocycles, and how to reason about them in a general way. 2010年02月10日再生回数 1602 |
