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Serotonin & Serotonin Receptor Antagonists
 
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www.SalmonellaPlace.com This is a tutorial/lecture on the Serotonin & Serotonin Receptor Antagonists. We cover some topics important for classes such as Biochemistry and Pharmacology. If you have any questions, don't be shy!! We hope we are able to clarify this topic. Enjoy! Plus, don't forget to SUBSCRIBE for more! Facebook: www.facebook.com/salmonellaplace Twitter: www.twitter.com/thesalmonella Tumblr: www.salmonellaplace.tumblr.com Images sources: "Serotonin 3D" http://commons.wikimedia.org/wiki/File:Serotonin_3D.PNG "Serotonin-3D-vdW" http://commons.wikimedia.org/wiki/File:Serotonin-3D-vdW.png "Vasoconstriction and Vasodilation" by Elizabeth2424 This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
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Membrane Structure and Transport - Kevin Ahern's BB 451 Lecture #32  2017
 
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Contact me at kgahern@davincipress.com Friend me on Facebook at kevin.g.ahern 1. Eicosanoids are compounds made from the 20 carbon fatty acid, arachidonic acid. These include prostanoids, thromboxanes, leukotrienes and endocannabinoids. 2. Prostaglandins are like hormones, but act very close to the point of synthesis. They stimulate swelling/inflammation, creating pain, uterine contractions, and the synthesis of intestinal tissue. 3. Prostaglandins are made from arachidonic acid by cyclooxygenases. Cyclooxygenases catalyze formation of a bond that creates a cyclic structure in arachidonic acid and adds one or more oxygens to it. 4. There are different COX enzymes, called COX 1, COX 2, and COX 3. 5. COX 1 enzymes are inhibited by aspirin and other related compounds. These compounds are called Non-Steroidal Anti-Inflammatory Drugs (NSAIDS). 6. Drug manufacturers sought inhibitors of COX 2 enzymes to see if they could make a pain-kiliing NSAID that didn't affect stomach tissue. Several, such as VIOXX and Celebrex were made, but some of them had negative effects on heart tissue and had to be withdrawn. 7. The cannabinoid known as anandamide is made from arachidonic acid and ethanolamine. It is called an endocannabinoid in animals and acts on specific brain receptors. Phytocannabinoids are compounds made in plants, such as marijuana, that affect the same receptors. 8. Endocannabinoids are responsible for pain reduction and experiences like runners' high. They are synthesized during periods of heavy exercise. I didn't mention it in class, but the receptor bound by endocannabinoids is the same one affected by chocolate. 9. Steroids are derived from cholesterol. Cholesterol is important for membrane stability. Cholesterol is prominent in brain membranes - up to 14% of the dry weight of brain. Compounds related to cholesterol made in plants are called phytosterols. 10. Cholesterol is a precursor of two important classes of compounds - steroid hormones and bile acids. Steroid hormones include mineralocorticoids, progestagens, glucocorticoids, and the sex hormones - androgens and estrogens. 11. Fat soluble vitamins include vitamins A,D, E, and K. Vitamin A comes in several forms.(Note - this is a correction from the video lecture). They include the alcohol form, known as retinol. This is primarily the storage form. An aldehyde form is known as retinal and is the form found in vision (wrongly stated in class as retinol). Retinal comes in two forms - the all trans form and a form with a single cis bond known as 11-cis retinal. All vision arises from isomerization of the 11-cis form in the eye to the all trans form. 12. Vitamin D is made from cholesterol. It is important for calcium and phosphate absorption/metabolism and the level of its active form is carefully controlled by the body. Synthesis of vitamin D in the body requires UV light. 13. Vitamin E is an antioxidant in the membrane bilayer and may protect against reactive oxygen species. 14. Vitmain K is involved in blood clotting. 15. A lipid bilayer has a polar exterior facing water and a non-polar interior. As such, the bilayer provides a barrier to polar and non-polar substances. Glycerophospholipids and sphingolipids in an aqueous environment will spontaneously form a lipid bilayer. 16. Lipids in lipid bilayers are not evenly distributed. 17. There are two types of movement of lipids in membranes - lateral or transverse. 18. Lateral movements occur freely and rapidly in fluid membranes. 19. Transverse movements require enzymes for movement from one side to the other. These include flippases, floppases, and scramblases. 20. Membrane fluidity is determined by the composition of fatty acids in the bilayer's glycerophospholipids and sphingolipids. Shorter, more unsaturated fatty acids favor more fluidity at lower temperatures. 21. Membranes transition from more solid-like to more liquid-like over a range of temperature. The mid-point of this temperature ranges is known as the Tm. 22. Cholesterol in a membrane has the effect of widening the range of transition, but does not change the Tm. Membrane Transport 1. Lipid bilayers create virtually impermeable barriers to movement of most molecules except water, carbon dioxide, carbon monoxide, and oxygen. 2. Most biochemicals do not readily cross lipid bilayers. Differences in concentration of these materials across a membrane, create electrical or chemical gradients. These are sources of potential energy. 3. Osmotic pressure is a good example of a potential energy created by a chemical gradient against a semi-permeable membrane. 4. Four types of membrane proteins are integral (protein projects through both sides of the membrane), peripheral (protein projects into only one side of the membrane), anchored (protein is linked to a molecule embedded in the lipid bilayer, or associated (protein associating with a membrane by interacting with a membrane protein).
Views: 1372 Kevin Ahern
Diet and Depression
 
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Is food connected to mood? A look at how diet can influence depression by exploring studies on individual foods and dietary intervention trials. - Links and Sources - https://www.patreon.com/micthevegan https://www.facebook.com/micthevegan https://www.instagram.com/micthevegan - @micthevegan https://plantspace.org TIY Tiny House Channel: https://www.youtube.com/channel/UCYhthOBh4_459pAge62at8g My Video on Women's Health / Vegetarian Depression Study: https://www.youtube.com/watch?v=9h2CfVveoH4 Dr. Greger: https://nutritionfacts.org/ Dopamine and Learning: http://www.pnas.org/content/108/Supplement_3/15647.full.pdf 1 in 8 people over 12 on anti-depressants: https://www.cdc.gov/nchs/data/databriefs/db283.pdf Fruit and Veggies Study 1: http://tinyurl.com/ya7txl9r Fruit and Veggies Study 2: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3520090/pdf/nihms-416644.pdf Whole Foods and Depression Study: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/19880930/ Polyphenols Study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3355196/pdf/nihms348384.pdf MAO Levels in 'Majorly Depressed Individuals': https://www.ncbi.nlm.nih.gov/pubmed/17088501 Quercetin and Luteolin MAO Study: https://reader.elsevier.com/reader/sd/E8260785936E88AC962465A677372D3465B49 40746FB7741E061D71EFA24F5B99A1DD5C4A491E370EB775C51651D05FA Vitamin C Co-factor in Dopamine Production: http://onlinelibrary.wiley.com/doi/10.1111/bjhp.12113/epdf USDA List of Quercetin and Luteolin in Foods: https://www.ars.usda.gov/ARSUserFiles/80400525/Data/Flav/Flav_R03.pdf Arachidonic Acid Levels in Food: https://epi.grants.cancer.gov/diet/foodsources/fatty_acids/table4.html How Arachidonic Acid Creates Inflammation Paper: http://dx.doi.org/10.1111/j.1471-4159.2006.04371.x Arachidonic Acid and Suicide/Depression: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4239694/pdf/nihms631389.pdf No Arachidonic Acid Study on Mood: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3293760/pdf/1475-2891-11-9.pdf Vegan Diet Resulted in 30% lower inflammation markers: https://www.researchgate.net/publication/271529631_C-reactive_protein_response_to_a_vegan_lifestyle_intervention CNN - 46 million turkeys article: http://www.cnn.com/2012/11/21/living/thanksgiving-by-the-numbers/index.html Tryptophan and turkey or carbs Study: http://ajcn.nutrition.org/content/77/1/128.full.pdf Depression Cured on Vegan Diet: https://www.forksoverknives.com/i-went-plant-based-and-left-life-threatening-depression-behind/#gs.VPxEBs0 High vs Low Carb and Depression Study: https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/1108558 PMS, carbs, and depression: http://www.ajog.org/article/0002-9378(89)90671-6/pdf Vegan Diet Worksite Intervention Study: http://www.pcrm.org/sites/default/files/pdfs/health/medstudents/A%20Worksite%20Vegan%20Nutrition%20Program%20Is%20Well-Accepted%20and%20Improves%20Health-Related.pdf Vegetarian Dietes Make You Depressed Origin Study: http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0088278&type=printable
Views: 69528 Mic the Vegan
Lecture #33 Ahern's BB 451 - Lipids & Membranes II
 
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Email me at kgahern@davincipress.com Friend me on Facebook at kevin.g.ahern 1. Prostanoids are 20 carbon compounds made from arachidonic acid that include the prostaglandins, and the thromboxanes (made from prostaglandins). Leuktrienes are made from linolenic acid. 2. Prostaglandins are molecules associated with numerous physiological phenomena, including pain. 3. Prostaglandins are made from arachidonic acid in a reaction catalyzed by peripheral membrane protein known as prostaglandin synthase (also called a cyclooxygenase = a COX enzyme). Non-steroidal anti-inflammatory drugs (NSAIDS) like aspirin or ibuprofen work by inhibiting the action of COX enzymes. 4. Some prostaglandins are necessary for synthesis of intestinal tissue, so inhibition of them by aspirin may cause stomach irritation, especially in people who take a lot of aspirin for things like rheumatoid arthritis. 5. An effort was made to inhibit a specific type of COX enzyme (COX-2 enzymes) commonly found in joints. Thus was born medications like VIOXX and CELEBREX, but many had to be recalled, due to having a side effect of damaging heart tissue. 6. Cannabinoids are eicosanoids that are called endocannabinoids (made by the body) or phytocannabinoids (made by plants). They bind brain receptors and exert various effects. Chocolate can also bind these receptors. Anandamide is made by combining arachidonic acid with ethanolamine. 7. Cholesterol is a steroid that is a precursor of steroid hormones and bile acids. It is an important component of membranes and makes up 14-16% of the dry tissue of brains. It acts by widening the transition temperature of membranes, but does not change the melting point. 9. Steroid hormones include the mineralocorticoids (ion balance), glucocorticoids (inflammation/immune response), progestagens (maintanance of pregnancy), estrogens (female sex hormones), and androgens (male sex hormones). Androgens are precursors of estrogens. The latter are made by action of an enzyme called an aromatase. 10. There are 4 fat soluble vitamins - A,D, E, and K. Vitamin D is made ultimately from cholesterol and exposure to ultraviolet light is a step in its synthesis. Vitamin D is important for the innate immune response. 11. Vitamin A comes in three chemical forms - an alcohol (retinol), an aldehyde (retinal - used in vision), and an acid (retinoic acid). Vision results from isomerization of all-trans retinal and 11-cis retinal by action of light on the molecule. 12. Vitmain E provide antioxidant protection to cell membranes from Reactive Oxygen Species (ROS). 13. Vitamin K is important for activation of prothrombin in the blood clotting process. Recycling of vitamin K is necessary for thrombin activation. Warfarin (used in some rat poison) acts by inhibiting recycling of vitamin K. It is also used as an anti-clotting agent in people. 14. Membranes are composed of a lipid bilayer and other molecules, such as cholesterol. The lipid bilayer contains two main categories of molecules - glycerophospholipids and sphingolipids. 15. A lipid bilayer has a polar exterior facing water and a non-polar interior. As such, the membrane provides a good barrier to both polar and non-polar substances. In contrast to the lipid bilayer, fatty acids aggregate into a micelle. 16. In addition to glycerophospholipids and sphingolipids, membranes contain proteins, glycoproteins, and glyolipids. Four types of membrane proteins are integral (protein projects through both sides of the membrane), peripheral (protein projects into only one side of the membrane), anchored (protein is linked to a molecule embedded in the lipid bilayer, or associated (protein associates by hydrogen bonding with an integral membrane protein. 17. Membranes provide a barrier between the cell and the external environment. Membranes provide a barrier to passage of many molecules, including molecules, such as sugar that the cell could use for food. 18. Integral membrane proteins span into and/or across the plasma membrane and thus must have both hydrophilic and hydrophobic portions that interact appropriately with the same portions of the plasma membrane. 19. One can assemble artificial lipid bilayers containing compounds as a means of delivering materials into cells. These artificial systems are called liposomes. Liposomes can carry substances and when the membrane of the liposome fuses with a cell membrane, the contents of the liposome are delivered into the cell. This is a useful way of getting compounds into cells that are not easily transported across the cell membrane in other ways. 20. Molecules move freely in each layer of the lipid bilayer (lateral diffusion), but do NOT readily flip from one side to the other. This is called transverse diffusion. 21.  Flippases are enzymes that catalyze transerse diffusion of molecules from the outside layer of a membrane to an inside layer.  Floppases catalyze the reverse movement.  Scramblases move molecules either way.
Views: 655 Kevin Ahern
15. Ahern's BB 350 at Oregon State University - Nucleic Acids
 
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Email me at kgahern@davincipress.com Friend me on Facebook at kevin.g.ahern 1. Vitamin A allows for the detection of light by being isomerized between the 11-cis and the all-trans form in the presence of light. 2. Vitamin K is required for the carboxylation of prothrombin. Prothrombin is the precursor of thrombin. This protein is necessary to convery fibrinogen to fibrin to make a clot. Carboxylation of prothrombin allows it to bind calcium and be held at the site of a wound. Warfarin is a drug that inhibits action of vitamin K and reduces the likelihood of blood clotting. 3. Arachidonic acid is a 20 carbon fatty acid (eicosanoid) with 4 double bonds. It is a precursor of the prostaglandins. Prostaglandins are molecules that are involved in pain and swelling, among other phenomena in the body. The enzyme catalyzing their synthesis is called cyclooxygenase (also called PGH Synthase or Prostaglandin Synthase). COX enzymes (there are several) are inhibited by aspirin and ibuprofen. These are known as NSAIDs (Non-steroidal anti-inflammatory drugs). 4. Steroids can also inhibit the release of arachidonic acid from cell membranes. 5. Some NSAIDS had harmful effects on heart valves and had to be recalled from the market. 6. Compounds related to prostaglandins include leukotrienes, which are involved in allergic responses and may also be involved in asthma, and thromboxanes, which are derived from prostaglandins and play roles in the stickiness of blood platelets. Nucleic Acids 1. Nucleic acids are composed of building blocks called nucleotides. Nucleotides have three components - a sugar (ribose or deoxyribose), at least one phosphate, and a nitrogenous base (adenine, guanine, thymine, cytosine, or uracil). 2. DNA differs from RNA in that DNA contains the sugar deoxyribose instead of ribose and DNA contains the base thymine, whereas RNA substitutes the base, uracil. 3. The bases in nucleic acids are divided into two groups. Pyrimidines include cytosine, thymine, and uracil. Purines include adenine and guanine. 4. A nucleoside differs from a nucleotide in that a nucleoside only has a sugar and a base. It does NOT have phosphate. 5. Note the numbering of the sugar in a nucleotide. The phosphate goes on carbon number 5. the differences between ribose and dexoyribose are on carbon #2, where ribose contains a hydroxyl, but deoxyribose contains only a hydrogen. 6. The 5' end of a nucleic acid is the end of the nucleic acid that has a free 5' end (no bond). The 3' end of a nucleic acid is the other end of the nucleic acid and it too is not tied up in a bond. All other 5' and 3' ends are joined together in phosphodiester bonds. 7. The "backbone" of a nucleic acid is composed of alternating phosphates and sugars and the bond linking them is called a phosphodiester bond. Phosphodiester bonds are to nucleic acids what peptide bonds are to proteins. The bases are NOT part of the backbone and in a DNA molecule are internal to the surrounding backbone. 8. The double helix of DNA was discovered by Watson, Crick, and Franklin in 1953. The most common form is called the B-form. It consists of two strands oriented in an anti-parallel fashion (slide 10) arranged in a right-handed fashion. Bases are located on the inside such that adenine forms 2 hydrogen bonds (pairs) with thymine and cytosine forms 3 hydrogen bonds with guanine. 9. Other forms of DNA duplexes include the A form (right handed also and also the form of double stranded RNA) as well as the Z form of DNA (left handed). 10. Supercoiling is one aspect of the structure of DNA. Bacterial chromosomes are circular, so if twists are inserted (or removed) from standard B DNA, supercoiling arises. 11. Chromatin is a complex of DNA and proteins. The proteins are called histones and they are positively charged. The repeating unit within chromatin is called a nucleosome. 12. Histones are proteins that associate with DNA and allow it to coil up. DNA-histone complexes are called nucleosomes. When you put many nucleosomes together, you get chromatin. Chromosomes contain chromatin. Each "ball" of histones contains four pairs of proteins - H2a, H2b, H3, and H4. 13. DNA strands can easily be separated by heat, acid, or base. 14. Single strands of nucleic acid (DNA or RNA) absorb light at 260 nm more strongly than double strands of nucleic acid in the same quantity. Thus, one can monitor the denaturation of nucleic acid by monitoring its absorbance at 260 nm as the denaturation proceeds. 15. The transition temperature (Tm) for a nucleic acid denaturation is the mid-point of the ™ transition.
Views: 619 Kevin Ahern
Kevin Ahern's BB 350 (Lipids & Membranes III / Nucleic Acids) 2014 - #14
 
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1. Contact me at kgahern@davincipress.com / Friend me on Facebook (kevin.g.ahern) 2. Download my free biochemistry book at http://biochem.science.oregonstate.edu/biochemistry-free-and-easy 3. Take my free iTunes U course at https://itunes.apple.com/us/course/biochemistry/id556410409 4. Check out my free book for pre-meds at http://biochem.science.oregonstate.edu/biochemistry-free-and-easy 5. Lecturio videos for medical students - https://www.lecturio.com/medical-courses/biochemistry.course 6. Course video channel at http://www.youtube.com/user/oharow/videos?view=1 7. Check out all of my free workshops at http://oregonstate.edu/dept/biochem/ahern/123.html 8. Check out my Metabolic Melodies at http://www.davincipress.com/ 9. My courses can be taken for credit (wherever you live) via OSU's ecampus. For details, see http://ecampus.oregonstate.edu/soc/ecatalog/ecourselist.htm?termcode=all&subject=BB 10. Course materials at http://oregonstate.edu/instruct/bb350 Highlights Lipids 1. Proteins on the cell surface can also act as 'receptors'. An example of a receptor that internalizes a compound is the LDL receptor, which binds to LDLs (cholesterol-containing complexes in the blood) and brings them inside of the cell. 2. Vitamin A is involved in vision thanks to its light sensitivity and a form of vitamin A is also involved in cellular differentiation. It works by having a double bond at position 11 in the moledule that is sensitive to light. When exposed to light, the bond converts from trans to cis, causing the molecule to change shape. Vitamin A is a component of the protein rhodopsin in the membrane of the rods and cone cells of the eye. Its change of shape is responsible for intitiating the nerve signal that results in our brain perceiving what we know as vision. 3. Vitamin D is involved in calcium and phosphate metabolism in the body. It is derived from cholesterol and its activation requires UV light. It is also necessary for a healthy immune system and has anti-cancer effects. 4. Vitamin E is a cellular antioxidant and probably protects membrane lipids from oxidation by reactive oxygen species. 5. Vitamin K is involved in the blood coagulation process. It is inhibited by the compound warfarin, which is used both as a rat poison and as a blood thinner. 6. Arachidonic acid is a 20 carbon fatty acid with 4 double bonds. It is a precursor of the prostaglandins. Prostaglandins are molecules that are involved in pain and swelling, among other phenomena in the body. Related compounds include leukotrienes, which are involved in allergic responses and may also be involved in asthma, and thromboxanes, which are derived from prostaglandins and play roles in the stickiness of blood platelets. 7. Arachidonic acid is converted to prostaglandins by enzymes known as cycloooxygenases (COX enzymes), which are inhibied by aspirin and ibuprofen - NSAIDs (Non-steroidal anti-inflammatory drugs). By preventing prostaglandin formation, they relieve pain. 8. The steroid cortisone is also anti-inflammatory. It works by inhitibiting the enzyme phospholipase A (PLA). PLA acts to release arachidonic acid from glycerophospholipids in cell membranes. Highlights /Nucleic Acids 1. Nucleic acids are composed of building blocks called nucleotides. Nucleotides have three components - a sugar (ribose in ribonucleotides of RNA or deoxyribose of deoxyribonucleotides of DNA), at least one phosphate, and a nitrogenous base (adenine, guanine, thymine, cytosine, or uracil). 2. DNA differs from RNA in that DNA contains the sugar deoxyribose instead of ribose and DNA contains the base thymine, instead of uracil. 3. A nucleoside has only has a sugar and a base. It does NOT have phosphate. 4. The phosphate in a nucleotide is on carbon number 5. the differences between ribose and dexoyribose are on carbon #2. 5. The 5' end of a nucleic acid is the end of the nucleic acid that has a free 5' end. The 3' end of a nucleic acid is the other end of the nucleic acid and it too is not tied up in a bond. 6. The "backbone" of a nucleic acid is composed of alternating phosphates and sugars and the bond linking them is called a phosphodiester bond. 7. The double helix of DNA was discovered by Watson, Crick, and Franklin in 1953. The most common form is called the B-form. 8. Thus, it will take more energy to break G-C bonds than A-T bonds. 9. Besides the most common B form of DNA, two other forms exist in cells. They include the A form and the Z form. Both the A and B forms have right handed helices, whereas the Z form has a left handed helix. 10. Supercoiling is one aspect of the structure of DNA. Bacterial chromosomes are circular, so if twists are inserted (or removed) from standard B DNA, supercoiling arises. 11. Chromatin is a complex of DNA and proteins called histones. 12. Histones are proteins that associate with DNA and cause DNA to coil around it, thus reducing its size.
Views: 866 Kevin Ahern
Ahern's BB 350 at OSU - 14. Nucleic Acids
 
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Contact me at kgahern@davincipress.com Facebook friend me at https://www.facebook.com/kevin.g.ahern 1. Arachidonic acid is a 20 carbon fatty acid (eicosanoid) with 4 double bonds. It is a precursor of the prostaglandins. Prostaglandins are molecules that are involved in pain and swelling, among other phenomena in the body. The enzyme catalyzing their synthesis is called PGH Synthase, Prostaglandin Synthase, or Cyclooxygenase (COX). COX enzymes (there are several) are inhibited by aspirin and ibuprofen. These are known as NSAIDs (Non-steroidal anti-inflammatory drugs). 2. Compounds related to prostaglandins include leukotrienes, which are involved in allergic responses and may also be involved in asthma, and thromboxanes, which are derived from prostaglandins and play roles in the stickiness of blood platelets. Nucleic Acids 1. Nucleic acids are composed of building blocks called nucleotides. Nucleotides have three components - a sugar (ribose or deoxyribose), at least one phosphate, and a nitrogenous base (adenine, guanine, thymine, cytosine, or uracil). 2. DNA differs from RNA in that DNA contains the sugar deoxyribose instead of ribose and DNA contains the base thymine, whereas RNA substitutes the base, uracil. 3. The bases in nucleic acids are divided into two groups. Pyrimidines include cytosine, thymine, and uracil. Purines include adenine and guanine. 4. A nucleoside differs from a nucleotide in that a nucleoside only has a sugar and a base. It does NOT have phosphate. 5. Note the numbering of the sugar in a nucleotide. The phosphate goes on carbon number 5. the differences between ribose and dexoyribose are on carbon #2, where ribose contains a hydroxyl, but deoxyribose contains only a hydrogen. 6. The 5' end of a nucleic acid is the end of the nucleic acid that has a free 5' end (no bond). The 3' end of a nucleic acid is the other end of the nucleic acid and it too is not tied up in a bond. All other 5' and 3' ends are joined together in phosphodiester bonds. 7. The "backbone" of a nucleic acid is composed of alternating phosphates and sugars and the bond linking them is called a phosphodiester bond. Phosphodiester bonds are to nucleic acids what peptide bonds are to proteins. The bases are NOT part of the backbone and in a DNA molecule are internal to the surrounding backbone. 8. The double helix of DNA was discovered by Watson, Crick, and Franklin in 1953. The most common form is called the B-form. It consists of two strands oriented in an anti-parallel fashion (slide 10) arranged in a right-handed fashion. Bases are located on the inside such that adenine forms 2 hydrogen bonds (pairs) with thymine and cytosine forms 3 hydrogen bonds with guanine. 9. Other forms of DNA duplexes include the A form (right handed also and also the form of double stranded RNA) as well as the Z form of DNA (left handed). 10. Supercoiling is one aspect of the structure of DNA. Bacterial chromosomes are circular, so if twists are inserted (or removed) from standard B DNA, supercoiling arises.
Views: 2324 Kevin Ahern