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Glucose-6-Phosphate: An ester of glucose with phosphoric acid, made in the course of glucose metabolism by mammalian and other cells. It is a normal constituent of resting muscle and probably is in constant equilibrium with fructose-6-phosphate. (Stedman, 26th ed)

Energy-requiring Steps of Glycolysis

JoVE 10738

Glucose is the source of nearly all energy used by organisms. The first step of converting glucose into usable energy is called glycolysis. Glycolysis occurs in the cytosol of the cell over two phases: an energy-requiring phase and an energy-releasing phase. Over the first three steps, glucose is converted into different forms and attaches to two phosphate groups donated by two ATP molecules, resulting in an unstable sugar. In the next two stages, the unstable sugar splits into two sugar isomers which are either converted or used directly in the next phase of glycolysis. First, glucose receives a phosphate group from ATP converting it into a more reactive form (glucose 6-phosphate). Because glucose attached to the negatively-charged phosphate cannot cross the hydrophobic cell membrane, the addition of a phosphate group also traps glucose inside the cell. Next, the more reactive form of glucose is converted into one of its isomers, fructose 6-phosphate, which is required for subsequent energy-requiring steps of glycolysis. Fructose 6-phosphate then receives a phosphate group from a second ATP molecule. This converts fructose 6-phosphate into fructose 1,6-bisphosphate, an unstable sugar. This unstable sugar splits into two distinct three-carbon sugar isomers, glyceraldehyde 3-phosphate and DHAP. Glyceraldehyde 3-phosphate can be directly use

 Core: Cellular Respiration

The Calvin Cycle

JoVE 10753

Oxygenic photosynthesis converts approximately 200 billion tons of carbon dioxide (CO2) annually to organic compounds and produces approximately 140 billion tons of atmospheric oxygen (O2). Photosynthesis is the basis of all human food and oxygen needs.

The photosynthetic process can be divided into two sets of reactions that take place in different regions of plant chloroplasts: the light-dependent reaction and the light-independent or “dark” reactions. The light-dependent reaction takes place in the thylakoid membrane of the chloroplast. It converts light energy to chemical energy, stored as ATP and NADPH. This energy is then utilized in the stroma region of the chloroplast, to reduce atmospheric carbon dioxide into complex carbohydrates through the light-independent reactions of the Calvin-Benson cycle. The Calvin-Benson cycle represents the light-independent set of photosynthetic reactions. It uses the adenosine triphosphate (ATP) and nicotinamide-adenine dinucleotide phosphate (NADPH) generated during the light-dependent reactions to convert atmospheric CO2 into complex carbohydrates. The Calvin-Benson cycle also regenerates adenosine diphosphate (ADP) and NADP+ for the light-dependent reaction. At the start of the Calvin-Benson cycle, atmospheric CO2 enters the leaf throug

 Core: Photosynthesis

Cofactors and Coenzymes

JoVE 10975

Enzymes require additional components for proper function. There are two such classes of molecules: cofactors and coenzymes. Cofactors are metallic ions and coenzymes are non-protein organic molecules. Both of these types of helper molecule can be tightly bound to the enzyme or bound only when the substrate binds.

Cofactors are present in ~30% of mature proteins. They are frequently incorporated into an enzyme as it is folded and are involved in the enzyme’s catalytic activity. Magnesium is an essential cofactor for over 300 enzymes in the human body, including DNA polymerase. In this case, the magnesium ion aids in the formation of the phosphodiester bond on the DNA backbone. Iron, copper, cobalt, and manganese are other common cofactors. Many vitamins are coenzymes, as they are nonprotein, organic helper molecules for enzymes. For example, biotin—a type of B vitamin—is important in a variety of enzymes that transfer carbon dioxide from one molecule to another.  Biotin, vitamin A and other vitamins must be ingested in our diet, as they cannot be made by human cells.

 Core: Metabolism

Phage Phenomics: Physiological Approaches to Characterize Novel Viral Proteins

1Department of Biology, San Diego State University, 2Computational Science Research Center, San Diego State University, 3Bioinformatics and Medical Informatics Research Center, San Diego State University, 4Department of Mathematics and Statistics, San Diego State University, 5Department of Computer Science, San Diego State University, 6Mathematics and Computer Science Division, Argonne National Laboratory, 7SPARC Committee, Broad Institute

JoVE 52854

 Immunology and Infection

An Optimized Protocol to Analyze Glycolysis and Mitochondrial Respiration in Lymphocytes

1Laboratory of Mitochondrial Biology and Metabolism, National Heart, Lung, and Blood Institute, National Institutes of Health, 2Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 3Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health

JoVE 54918

 Immunology and Infection

Dried Blood and Serum Spots As A Useful Tool for Sample Storage to Evaluate Cancer Biomarkers

1Osteoncology and Rare Tumors Center, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy, 2Unit of Biostatistics and Clinical Trials, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy, 3Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy, 4Department of Oncology, Bugando Medical Center, Mwanza, Tanzania

JoVE 57113

 Cancer Research

Optimized Protocol for the Extraction of Proteins from the Human Mitral Valve

1Centro Cardiologico Monzino IRCCS, 2Cardiovascular Tissue Bank of Milan, Centro Cardiologico Monzino IRCCS, 3Department of Clinical Sciences and Community Health, Cardiovascular Section, University of Milan, 4Department of Cardiovascular Disease, Development and Innovation Cardiac Surgery Unit, Centro Cardiologico Monzino IRCCS

JoVE 55762


Non-invasive In Vivo Fluorescence Optical Imaging of Inflammatory MMP Activity Using an Activatable Fluorescent Imaging Agent

1Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University of Tübingen, 2Department of Nuclear Medicine, Eberhard Karls University of Tübingen, 3Department of Dermatology, Eberhard Karls University of Tübingen

JoVE 55180

 Immunology and Infection

Extraction of Aqueous Metabolites from Cultured Adherent Cells for Metabolomic Analysis by Capillary Electrophoresis-Mass Spectrometry

1Shonai Regional Industry Promotion Center, 2Tsuruoka Metabolomics Laboratory, National Cancer Center, 3Human Metabolome Technologies, Inc, 4Division of Translational Informatics, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center

JoVE 59551

 Cancer Research

Inactivation of mTor: A Tool to Investigate Meiotic Progression and Translational Control During Bovine Oocyte Maturation

1BVN Neustadt/Aisch, 2Faculty of Veterinary Medicine, Clinic for Obstetrics, Gynecology and Andrology of Large and Small Animals, Justus-Liebig-University Giessen, 3Reproductive Cell Biology Unit, Leibniz Institute for Farm Animal Biology, 4Reproductive Biochemistry Unit, Leibniz Institute for Farm Animal Biology

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JoVE 53689

 JoVE In-Press
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