Cholesterol structure and synthesis

Cholesterol Synthesis

Cholesterol Structure Figure: Cholesterol Structure Although cholesterol is synthesized in most tissues of the body where it serves as a component of cell membranes, it is produced mainly in the liver and intestine. Cholesterol and cholesterol esters are transported in blood lipoproteins. All the carbons of cholesterol are derived from acetyl-CoA. The key intermediates in cholesterol biosynthesis are HMG-CoA, mevalonic …

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Pentose Phosphate Pathway

Pentose Phosphate Pathway

Pentose Phosphate Pathway The pentose phosphate pathway is a metabolic pathway parallel to glycolysis which generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-phosphate. The pentose phosphate pathway is also called as the phosphogluconate pathway or hexose monophosphate shunt. While it involves oxidation of glucose, its primary role is anabolic rather than catabolic.  It is an important pathway that generates precursors for nucleotide synthesis andis especially important in red blood cells (erythrocytes). Location Cytoplasm of cells of the liver, adrenal …

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Urea Cycle- Enzymes and Steps

Urea Cycle- Enzymes and Steps

Urea Cycle- Enzymes and Steps The urea cycle is the metabolic pathway that transforms nitrogen to urea for excretion from the body. Nitrogenous excretory products are removed from the body mainly in the urine. Ammonia, which is very toxic in humans, is converted to urea, which is nontoxic, very soluble, and readily excreted by the kidneys. The urea excreted each …

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Lipids- definition, properties, structure, types, examples, functions

Lipids- Properties, Structure, Classification and Functions

Lipids definition Lipids are a heterogeneous group of organic compounds that are insolub­le in water and soluble in non-polar organic solvents. They naturally occur in most plants, animals, microorganisms and are used as cell membrane components, energy storage molecules, insulation, and hormones. Properties of Lipids Lipids may be either liquids or non-crystalline solids at room temperature. Pure fats and oils …

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Gluconeogenesis- Steps, Reactions and Significance

Gluconeogenesis- Steps, Reactions and Significance

Gluconeogenesis- Steps, Reactions and Significance Gluconeogenesis is the production of glucose from non-sugar precursors. Gluconeogenesis, mainly occurs in the liver, and involves the synthesis of glucose from compounds that are not carbohydrates. When a cell is growing on a hexose such as glucose, and obtaining glucose for polysaccharide synthesis, there is no problem. But when the cell is growing on …

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Amino Acids- Properties, Structure, Classification and Functions

Amino Acids- Properties, Structure, Classification and Functions

Amino acids constitute a group of neutral products clearly distinguished from other natural compounds chemically, mainly because of their ampholytic properties, and biochemically, mainly because of their role as protein constituents. An amino acid is a carboxylic acid-containing an aliphatic primary amino group in the α position to the carboxyl group and with a characteristic stereochemistry. Proteins are biosynthesized from …

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Nucleic Acids- Nucleosides and Nucleotides

Nucleosides and Nucleotides

Nucleic Acids- Nucleosides and Nucleotides Nucleotide is any member of the class of organic compounds in which the molecular structure comprises a nitrogen-containing unit (base) linked to a sugar and a phosphate group.  They are monomeric units of nucleic acids and also serve as sources of chemical energy (ATP, GTP), participate in cellular signalling (cAMP, cGMP) and function as important cofactors of enzymatic reactions …

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Electron Transport Chain (ETC)- Components and Steps

Electron Transport Chain (ETC)- Components and Steps

The NADH and FADH2 formed in glycolysis, TCA cycle and fatty acid oxidation are energy-rich molecules because they contain a pair of electrons that have high transfer potential. ATP is generated as a result of the energy produced when electrons from NADH and FADH2 are passed to molecular oxygen by a series of electron carriers, collectively known as the electron …

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TCA Cycle (Citric acid cycle or Krebs cycle)

Krebs cycle

TCA Cycle (Citric acid cycle or Krebs cycle) The tricarboxylic acid cycle (TCA cycle), also known as the citric acid cycle or the Krebs cycle, is a major energy-producing pathway in living bodies. Cells obtain ATP from breakdown of glucose in the absence of oxygen as in glycolysis. However, most organisms normally are aerobic and oxidize their organic fuels completely …

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Proteins- Properties, Structure, Classification and Functions

Proteins- Properties, Structure, Classification and Functions

Proteins- Properties, Structure, Classification and Functions Proteins are the most abundant biological macromolecules, occurring in all cells. It is also the most versatile organic molecule of the living systems and occur in great variety; thousands of different kinds, ranging in size from relatively small peptides to large polymers. Proteins are the polymers of amino acids covalently linked by the peptide …

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