

Biochemistry and Molecular Biology: How Life Works
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Episodi
S1 E1 - Biochemistry Is the Science of Us
12 settembre 201931minGet started on the subjects that Professor Ahern calls “the science of us”: biochemistry and its allied field molecular biology, which both tell us who we are. Discover the handful of elements involved in biochemical reactions; the bonds they form; and the wide array of molecules that result, including amino acids, which are the building blocks of proteins.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E2 - Why Water Is Essential for Life
12 settembre 201931minInvestigate why water is so singularly suited to life. Composed of two hydrogen atoms for each oxygen atom, water molecules have a polar charge due to the uneven arrangement of shared electrons. See how this simple feature allows water to dissolve sugars and salts, while leaving oils and fats untouched. Also learn what makes water solutions acidic or basic.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E3 - Amino Acids: 20 Building Blocks of Life
12 settembre 201929minTake a tour through the 20 amino acids that link together in different combinations and sequences to build proteins. Besides water, proteins are the most abundant molecules in all known forms of life. Also the most diverse class of biological molecules, proteins make up everything from enzymes and hormones to antibodies and muscle cells.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E4 - From Peptide Bonds to Protein Structure
12 settembre 201930minLearn how peptide bonds join amino acids to form an almost unlimited number of protein types. The order of amino acids matters, but even more important are the shapes they form. Survey primary, secondary, tertiary, and quaternary protein structures, with examples from silk (a fibrous protein with mostly secondary structure) to the intricately folded hemoglobin protein (a quaternary structure).Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E5 - Protein Folding, Misfolding, and Disorder
12 settembre 201932minDiscover how proteins fold into complex shapes, often with the help of molecular chaperones. Then learn the deadly consequences of proteins that do not fold properly, leading to degenerative conditions such as Alzheimer’s, Parkinson’s, and prion diseases. Also look at intrinsically disordered proteins, which lack a fixed structure, permitting flexible interactions with other biomolecules.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E6 - Hemoglobin Function Follows Structure
12 settembre 201929minHemoglobin is the protein in red blood cells that carries oxygen from lungs to tissues and then takes away carbon dioxide for exhalation. Learn how structure is the key to this complicated and vital function. Also see how variant forms of hemoglobin, such as fetal hemoglobin and the mutation behind sickle cell anemia, can have life-saving or fatal consequences - all depending on structure.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E7 - Enzymes' Amazing Speed and Specificity
12 settembre 201931minWitness how structure and function are related in enzymes, which are a group of proteins that stimulate biochemical reactions to run at astonishing speed. One example is OMP decarboxylase, an enzyme that produces a crucial component of DNA in a blistering 0.02 second, versus the 78 million years that the reaction would normally take! Analyze the mechanisms behind these apparent superpowers.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E8 - Enzyme Regulation in Cells
12 settembre 201931minHow do cells control the tremendous power of enzymes? Study the ways that cells regulate enzyme activity by directing the synthesis and breakdown of biomolecules. One reason biochemists care so much about enzymes is that many medical conditions result from enzyme activity that is excessive or insufficient. Consider examples such as hemophilia, hypertension, and high cholesterol.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E9 - Fatty Acids, Fats, and Other Lipids
12 settembre 201932minLipids are a varied group of molecules that include fats, oils, waxes, steroids, hormones, and some vitamins. Survey the fats that obsess us in our diets and body shapes, notably triglycerides in their saturated and unsaturated forms. Then explore the role lipids play in energy storage and cell membrane structure, and cover the multitude of health benefits of the lipid vitamins: A, D, E, and K.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E10 - Sugars: Glucose and the Carbohydrates
12 settembre 201931minProbe the biochemistry of sugars that provide us with instant energy, feed our brains, direct proteins to their destinations, and communicate the identity of our cells. On the other hand, when present in large quantities, they can lead to Type 2 diabetes, and the wrong sugar markers on transfused blood cells can even kill us.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E11 - ATP and Energy Transformations in Cells
12 settembre 201933minAdenosine triphosphate (ATP) is the fuel that powers many processes in living cells. Every day we make and break down our own body weight in ATP. Focus on the chemical reactions behind this impressive energy conversion system, which is governed by the Gibbs free energy equation. These reactions, which can proceed either forward or backward, are among the most important in biochemistry.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E12 - Breaking Down Sugars and Fatty Acids
12 settembre 201932minA metabolic pathway is a series of biochemical reactions, where the product of one serves as the substrate for the next. Biochemists compare these pathways to road maps that show the network of reactions leading from one chemical to the next. Follow the metabolic pathway called glycolysis that breaks up glucose and other sugars. Then trace the route for fatty acid oxidation.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E13 - Metabolism Meets at the Citric Acid Cycle
12 settembre 201932minThe products from the reactions in the previous lecture now enter the Krebs citric acid cycle. The outcome of these reactions, in turn, link to many other pathways, with the Krebs cycle serving as the hub directing the intricate traffic of metabolic intermediates. After decoding the Krebs cycle, use it to illuminate a deep mystery about cancer cells, which suggests new therapies for the disease.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E14 - Energy Harvesting in Animals and Plants
12 settembre 201933minThus far, your investigations have accounted for only part of the energy available from food. So where’s all the ATP? In this episode, see how ATP is produced in abundance in both animal and plant cells, largely via mitochondria (in animals and plants) and chloroplasts (in plants only). You also learn why we need oxygen to stay alive and how poisons such as cyanide do their deadly work.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E15 - How Animals Make Carbs and Fats
12 settembre 201931minTake a tour of cell manufacturing, focusing on metabolic pathways that use energy to synthesize key molecules, including sugars, complex carbohydrates, fatty acids, and other lipids. Along the way, learn why alcohol and exercise don’t mix, how our bodies create short- and long-term energy stores, and why some essential fatty acids can lead to health problems if their ratios are not optimal.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E16 - Cholesterol, Membranes, Lipoproteins
12 settembre 201935minThe word “cholesterol” evokes fear in anyone worried about coronary artery disease. But what is this ubiquitous lipid and how harmful is it? Examine the key steps in cholesterol synthesis, learn about its important role in membranes, and discover where LDLs (“bad” cholesterol) and HDLs (“good”) come from. It isn’t cholesterol alone that is plugging arteries in atherosclerosis.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E17 - Metabolic Control during Exercise and Rest
12 settembre 201931minSee how cells manage complex and interconnected metabolic pathways, especially in response to exercise and a sedentary lifestyle. Then discover the secret of warm-blooded animals and what newborn babies have in common with hibernating grizzly bears (with lessons for combatting obesity). Also, learn about a drug from the 1930s that helped people burn fat in their sleep, as it killed them.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E18 - How Plants Make Carbs and Other Metabolites
12 settembre 201930minStudy how plants use sunlight and reduction reactions to build carbohydrates from carbon dioxide and water. This synthesis of food from air and water occurs in a series of reactions called the Calvin cycle. While humans exploit plants for food and fiber, we also utilize a multitude of other plant molecules called secondary metabolites. These include flavors, dyes, caffeine, and even catnip.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E19 - Recycling Nitrogen: Amino Acids, Nucleotides
12 settembre 201930minNitrogen is a key component of amino acids, DNA, and RNA, yet animal and plant cells are unable to extract free nitrogen from air. See how bacteria come to the rescue. Then follow the flow of nitrogen from bacteria to plants to us. Also look at strategies for reducing our reliance on environmentally unsound nitrogen fertilizers by exploiting the secret of 16-feet-tall corn plants found in Mexico.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E20 - Eating, Antioxidants, and the Microbiome
12 settembre 201930minDiscover how to eat in a way that minimizes harm and efficiently fixes the inevitable damage from living. Learn that certain cooking methods can increase the formation of harmful compounds. And substances such as antioxidants found in some foods can reduce the impact of damaging chemical reactions within cells. Also cover recent findings about gut bacteria that have changed our views about diet.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E21 - Hormones, Stress, and Cell Division
12 settembre 201932minCellular communication depends on specific molecular interactions, where the message and the receiver are biomolecules. Follow this process for signaling molecules such as the hormones epinephrine, adrenalin, and epidermal growth factor, which stimulates cells to divide. Cellular signaling is like the children’s game called telephone, except the message is usually conveyed accurately!Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E22 - Neurotransmitters, the Brain, and Addiction
12 settembre 201930minWhen you touch a hot stove, you recoil instantly. How do nerve cells process information so quickly? Trace nerve impulses (which involve electrical signals and neurotransmitters) as they pass from neuron to neuron, and from neuron to muscle cells. Study molecules that block nerve transmissions, such as snake venom and Botox treatments, and look at the role of dopamine in addiction behaviors.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E23 - The Biochemistry of Our Senses
12 settembre 201929minMost of the reactions you have studied so far occur outside everyday awareness. Now investigate the most important biochemical signals that we habitually notice: the molecular reactions that give rise to the five senses. Analyze the sensory origins of colors, sounds, tastes, smells, and touch, mapping them through the nervous system. Observe how the senses are “tuned” to enhance our survival.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E24 - From Biochemistry to Molecular Biology
12 settembre 201929minTrace the pathways of two widely ingested molecules: caffeine and fructose. Caffeine fools the body (usually harmlessly) into increasing glucose in the blood, while too much fructose can lead to unhealthy accumulation of fat in the liver. Then focus on two topics that link with the upcoming molecular biology segment of the series: androgen insensitivity and the molecular mechanisms of aging.Periodo d’uso gratuito di The Great Courses Signature Collection o acquistoS1 E25 - DNA and RNA: Information in Structure
12 settembre 201930minAdvance into the last third of the series, where you cover molecular biology, which deals with the biochemistry of reproduction. Zero in on DNA and how its double-helix structure relates to its function. Then look at the single-stranded RNA molecule, which is a central link in the process, “DNA makes RNA makes protein.” Also consider how viruses flourish with very little DNA or RNA.Periodo d’uso gratuito di The Great Courses Signature Collection o acquisto