Biology Chemistry

• Lipids are commonly defined as fats, which are known to contribute to major diseases such as heart disease.
• Lipids, in the form of triacylglycerol (TAG), are also known as fat.
• There are many misconceptions about lipids, including the common understanding that when fats are mentioned, they are always referred to as bad.
• Lipids have various properties, classifications, and functions.
• Lipids can be classified based on their functions, physicochemical properties, and transport and shuttle systems used in lipids.
• Lipids can be categorized based on their physicochemical properties, including saturation, monounsaturation, and polyunsaturation.
• Lipids play a crucial role in the etiology, symptoms, and treatment of various lipid-related diseases.
• Lipids are a type of biomolecule that can be characterized by their structures, uses, and functions.
• Lipids can be classified based on their structures, including simple and complex lipids.
• The structural formulas of these types of lipids illustrate the great structural diversity among lipids.
• Unlike carbohydrates and most other classes of compounds, lipids do not have a common structural feature that serves as the basis for defining such compounds.
• The characterization of lipids is based on solubility characteristics.
• Lipids are organic compounds found in living organisms that are insoluble in water but soluble in nonpolar organic solvents.
• Lipids present in inner mitochondrial membrane actively participate in electron transport chain.
• Combinations of lipid and protein (lipoproteins) are important cellular constituents, occurring both in the cell membrane and in the mitochondria, and serving also as the means of transporting lipids in the blood.
• Large amount of energy is stored as lipid than as carbohydrates.
• Lipids serve also as a source of fat-soluble vitamins (Vitamin A, D, E and K) and essential fatty acids (Linoleic, Linolenic and Arachidonic acid).
• Lipids are efficient energy sources that can be stored in the body in almost unlimited amount in contrast to carbohydrates.
• The defining parameter for lipids is solubility rather than structure.
• Lipids serve as thermal insulators, protecting internal organs from atmospheric heat and cold.
• Lipids can be categorized into five categories based on chemical function: membrane lipids (phospholipids, sphingolipids, cholesterol), emulsifying lipids (bile acids), messenger lipids (steroid hormones and eicosanoids), protective-coating lipids (biological waxes), and saponifiable lipids (TAG, phospholipids, sphingoglycolipids, and biological waxes).
• Nonpolar lipids act as electrical insulators, allowing rapid propagation of depolarization waves along myelinated nerves.
• Lipids have a high calorific value (calories per gram) which is twice as great as carbohydrate.
• Fatty acids are the monomer unit of lipids, are naturally occurring monocarboxylic acids, and can be categorized based on carbon chain length: long-chain fatty acids (C12 to C26), medium-chain fatty acids (C8 and C10).
• Lipids serve as precursors for hormones (exsteroid hormones) and dissolve the vitamins, which are fat-soluble and assist their digestion.
• Lipids are structural components of the cell membrane, responsible for membrane integrity and regulation of membrane permeability.
• Eicosanoids, or lipid messengers, are fatty acid derivatives that function as messenger lipids.
• The structure of norethynodrel (Enovid), a synthetic progestin, is similar to that of progesterone, the real hormone.
• The synthetic estrogen in oral contraceptive pills regulates the menstrual cycle, and the synthetic progestin prevents ovulation, thus creating a false state of pregnancy.
• Estriol also may be measured in men or women who might have cancer of the ovaries, testicles, or adrenal glands.
• Estriol may be measured in women who have gone through menopause to determine their estrogen levels.
• Cortisone and prednisolone, similar synthetic derivatives of cortisol, are used as prescription drugs to control inflammatory diseases such as rheumatoid arthritis.
• The amount of estradiol in a woman's blood varies throughout her menstrual cycle.
• After menopause, estradiol production drops to a very low but constant level.
• Estriol can also be measured in urine.
• Oral contraceptive pills are used to suppress ovulation as a method of birth control.
• Cortisol (Hydrocortisone) is a glucocorticoid that exerts powerful anti-inflammatory effects in the body.
• Estriol can be detected as early as the 9th week of pregnancy, and its levels increase until delivery.
• RU-486, the controversial “morning after” pill developed in France, is similar in structure to progesterone and interferes with gestation of a fertilized egg and terminates a pregnancy within the first nine weeks of gestation more effectively and safely than surgical methods.
• Anabolic steroids, including the illegal steroid drugs used by some athletes to build up muscle strength and enhance endurance, are known to have serious side effects in the user.