Unit 3

Biological Significance of Vitamin D and Conversion of Cholesterol into Vitamin D

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Vitamin D, often referred to as the “sunshine vitamin,” is a fat-soluble vitamin essential for various bodily functions, especially calcium and phosphate homeostasis. Its synthesis begins with cholesterol and involves several steps, including exposure to ultraviolet B (UVB) radiation from sunlight.  Biological Significance of Vitamin D 1. Calcium Homeostasis and Bone Health: Calcium Absorption: Vitamin … Read more

Biological Significance of Steroid Hormones and Conversion of Cholesterol into Steroid Hormones

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Steroid hormones are a class of hormones derived from cholesterol that play crucial roles in regulating a wide range of physiological processes. They include glucocorticoids, mineralocorticoids, and sex steroids. The synthesis of these hormones from cholesterol is a complex process involving multiple enzymatic steps. Biological Significance of Steroid Hormones Steroid hormones exert their effects by … Read more

Biological Significance of Cholesterol and Conversion of Cholesterol into Bile Acids

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Cholesterol is a crucial lipid molecule with significant roles in cellular structure, hormone synthesis, and digestion. Its conversion into bile acids is a vital pathway for maintaining cholesterol homeostasis and facilitating the digestion and absorption of dietary fats. Biological Significance of Cholesterol 1. Component of Cell Membranes Membrane Fluidity: Cholesterol is a key component of … Read more

De Novo Synthesis of Fatty Acids (Palmitic Acid)

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De novo synthesis of fatty acids is a crucial metabolic process in which acetyl-CoA is converted into fatty acids. This process primarily occurs in the cytoplasm of liver cells (hepatocytes), adipose tissue, and mammary glands during lactation. Palmitic acid (C16:0) is the primary product of this pathway and serves as a precursor for other fatty … Read more

Formation and Utilization of Ketone Bodies; Ketoacidosis

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Ketone bodies are water-soluble molecules produced by the liver during periods of low carbohydrate intake, prolonged fasting, or intense exercise. They serve as an alternative energy source when glucose is scarce. The primary ketone bodies are acetoacetate, β-hydroxybutyrate, and acetone. This note will provide a detailed overview of the formation and utilization of ketone bodies, … Read more

Lipid Metabolism: β-Oxidation of Saturated Fatty Acid (Palmitic Acid)

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Lipid metabolism is a complex process involving the breakdown, synthesis, and regulation of fats within the body. One of the key processes in lipid metabolism is β-oxidation, a catabolic pathway by which fatty acid molecules are broken down in the mitochondria to generate acetyl-CoA, NADH, and FADH2. This note will provide a detailed overview of … Read more