PDF Amphipathic Lipids, Eicosanoids And Terpenes

Okay, here is the transcription of the images into a structured markdown format: ## Amphipathic Lipids They are a class of molecules that play a Crucial role in the formation of biological membranes. These molecules have a unique structure consisting of two distinct regions: ### Hydrophilic head...

Okay, here is the transcription of the images into a structured markdown format: ## Amphipathic Lipids They are a class of molecules that play a Crucial role in the formation of biological membranes. These molecules have a unique structure consisting of two distinct regions: ### Hydrophilic head This part of the molecule is water-loving i.e. they interact favourably with water molecules. They are typically polar or charged, i.e. they are composed of polar groups like phosphate, carboxyl or hydroxyl groups. ### Hydrophobic tail These regions are water-hating or water-repelling i.e. they tend to avoid water molecules but instead interact with other non-polar substances. They are totally typically composed of long-chain hydrocarbons. This dual nature allows amphipathic lipids to self-assemble into various structures in aqueous environments, with the hydrophilic heads interacting with water and the hydrophobic tails clumping together to minimize their contact with water. It also makes them an essential component of biological membranes and other biological processes. Examples of Amphipathic Lipids #### Phospholipids These are the most abundant lipids in cell membranes. They have a glycerol backbone and two fatty acids and a phosphate group linked to a variety of head groups e.g. C. choline, serine, integrated ethanolamine. Chemical structure: $CH_2+CH=CH_2$ $CH_2(CH_2)_{n-1}CO-$ $CH_2(CH_2)_{n-1}CO-$ ## Importance of Amphipathic Lipids in Membrane Formation The amphipathic nature of these lipids is essential for the formation of stable self-sealing lipid bilayers, the fundamental structures of cell membranes. In a lipid bilayer, the hydrophilic heads face the aqueous environment on either side, while the hydrophobic tails are shielded from water by interacting with each other in the bilayer structure interior. Diagram of lipid bilayer: a diagram showing extracellular fluid above a phospholipid bilayer. The hydrophilic heads are exposed on the top and bottom, and the hydrophobic tails meet in the centre of the membrane. Below the membrane is the intracellular fluid. This arrangement creates a barrier that separates the cell's interior from its external environment, allowing the cell to maintain a distinct internal composition and regulate the passage of ions in and out. Other biological importances include: ### Membrane formation In which amphipathic lipids self-assemble into bilayers. ### Micelle and liposome formation Which are involved in encapsulating and transporting hydrophobic molecules, for honour structures. ### Signalling molecule Some amphipathic lipids act as precursors for signalling molecules such as prostaglandins (they are produced from anadonic acids/inmuved with pain regulation & inflammations). ### Surface active agents Amphipathic lipids reduce surface tension in ageous solutions which is critical in processes like digestion e.g. ## Eicosanoids - They are a class of signalling molecules derived from 20 carbon polyunsaturated fatty acids primarily arachidonic acid. They play crucial roles in various physiological processes including inflammation immunity and the imbal nervous system. ### Chemistry of Eicosanoids Eicosanoids are characterized by a 20 carbon backbone with various functional groups such as: * Hydroxyl (OH) * Carbonyl (C=O) * Carboxyl (COOH) These functional groups contribute to their diverse biological activities. Eicosanoids are synthesized through enzymatic oxidation of arachidonic acids, which is released from the inmembrane phospholipid by the action of phospholipase A2. The major enzymes involved in licosanoid biosynthesis are cyclooxygenases (COX) and lipuo oxygenase (LOX). **Diagram of Eicosanoid synthesis pathways:** a diagram illustrating the synthesis of eicosanoids from diacylglycerol or phospholipids, involving phospholipase A2, arachidonic acid, LOX, HPETE, PGH2 synthase (COX1 or COX2), prostaglandins (such as PGD2, PGE2, PGF2⍺), prostacyclin (PGI2), and thromboxanes (TXA2). * *HPETE*: Hydroperoxy-eicosatetraenoic acid. * *GST*: Glutathione S-transferase. * *PG*: Prostaglandin. * *LT*: Leukotriene. ## Types of Eicosanoids ### Prostaglandins These are a group of eicosanoids with a wide range of physiological effects such as vaso-dilation, inflammation and pain. They are synthesized by the COX pathway. They contain a cyclo-pentane ring, they are sub-classified based on the functional groups and the number of double bonds. Example include: PGE2, PGF. Chemical structure of PGE2: $PGE2 structure: a five-membered ring (cyclopentane) is attached to fatty acid chains. One chain has a carbonyl group (C=O) and another chain includes an alcohol group (OH). $CH_2CH = CH(CH_2)_3COOH$ $CH = CH(CH_2)_4CH_3$ ### Thromboxanes They are similar to prostaglandins but have a 6-membered oxygen-containing ring (oxane ring). They play a key role in platelet aggregation, blood clot formation, and vaso-constriction. They are synthesized by the COX pathway. ### Leukotrienes They are linear compounds with conjugated double bonds and hydroxyl groups - they are involved in allergic reactions and inflammation, they are synthesized by the LOX pathway. ### Lipoxins They are non-cyclic derivatives with hydroxyl groups and double bonds. They are anti-inflammatory agents and are signalling molecules derived from arachidonic acid. Unlike many other eicosanoids, such as prostaglandins and leukotrienes which primarily promote inflammation, lipoxins play a critical role in resolving inflammation. ### The Release of Arachidonic Acid The release of arachidonic acid follows two major pathways which are: * **Cyclooxygenase pathway:** This involves the use of cyclooxygenase and cyclooxygenase (COX 1 and COX 2). They convert arachidonic acid to prostaglandin that which is the precursor for both prostaglandin and thromboxanes. * **Lipoxygenase pathway:** It involves the use of lipoxygenase which converts arachidonic acids into hydroperoxy-HPETE which is used to produces leukotrienes and lipoxins. ### Physiological notes of Eicosanoids * **Inflammation:** in which leukotrienes and prostaglandins are used to mediate, fever, pain and swelling. * **Blood clotting:** Thromboxane A2 promotes platelet aggregation * **Asthma and allergy:** This involves the use of leukotrienes which contribute to broncho-constriction and mucus Secretion. * **Resolution of inflammation:** Here, lipoxins help terminate inflammatory responses. ## Terpenes Drugs such as NSAIDS (non-steroidal anti-inflammatory drugs). Such as Aspirin, Ibrupofen inhibits COX enzymes which produce prostaglandins. **Terpenes Chemistry of Prostala** Terpenes are a large and diverse class of organic compounds produced by plants, micro organisms, and some animals. They are hydrocarbon consisting of repeating units of (Isoprene $(C_5H_8)$ , making them members of the looprenoid family. Terpenes are clearacterised by their distinctive fragrances and Oils. They have significant roles in biological, Pharmaceutical and Industrial applications as well as plant defence, pollination, and human health. **Chemical Structure and classification.** Terpenes ate built from wsoprene units which are 5-carbon molecules $(C_5H_8)$. Isoprene structure: a molecule made of 5 carbon atoms and 8 hydrogen atoms is laid out. ## Types of Terpenes ### Myrcene Chemical structure: shows five different locations with numbers on them ### Limonene Chemical structure: shows five different locations with numbers on them ### Retinol Chemical structure: shows five different locations with numbers on them A terpene that does not obey the ssoprene rule is Ca ### Irregular Terpene Structure of Beta-carotene. It shows five different locations with numbers on them ## Multiple Isoprene Limits Teipenes are formed by linking multiple isoprene units together the number of the isoprene unit determines the classification of the terpene. ### Monoterpenes This contains 2 180 prene units ($C_{10}H_{16}$ Example is the limonene, which I found in Cilmes, metre Cene which is found in the hops ### Sesquiterpenes ($C_{15}H_{24}$) Is Composed of three 100prene units example Faine Sene if is found in apples. Humlene it is found in hops. ### Diterpenes ($C_{20}H_{32}$) it is made up of 4 isoprene units Examples: Taveor antip carcinogen Retinol vitamin a precursors ### Triterpenes $(C_{30}H_{48})$ it is composed of 6 soprene units, Examples: Squalene ( cholesterol precursor). and Lanstent ants ### Tefraterpenes $(C_{40}H_{64})$ it is made up of 8 Isoprene units Examples: Carotenoids like B Carotene (precursor of vitamen A) and lycopene Cusually found in tomato). ## Structural Diversity Terpenes exhibit a wide range of Sructural variations such as ### Linear That is an open Cham Structure. ### Cyclic Those Are ving Structure and the could be mono Cyelic, Bi-Cyclic or tricyclre. ### Oxygenated derivatives Thase are terpenoids which contain oxygen containing functional groups such as alcohol, Retinol, Ketones, aldehydes and ethers ## Functional Groups in Terpenes tetpens Contain functional groups depending on their oxidation State eg: ### Hydroxyl (-OH) Groups These are found in alioka terpenes la menthoStructure of Menthol molecules is presented. ### Carbonyl (C = O) Groups These are found in defore, teipenes like Camphor The structure of carbon molecules is shown. ### Double Bonds These allow for Structural diuisaties and reactivity ### Epoxide Groups These are found in oxidized terpenes like limonene, overde. ## Chemical Propeties ### Volatility They have low molecular weight terpenes such as monoterpenes are volatile and Contribute to the aroma of plants. ### Hychophobicity most terpenes Pngtare non-poplat and dissolve in lipid and organic souvents but not water ### Reactivity the presence of double bond alloves terpenes to undet-go addition reaction such as hydrogenation and halogenation. Terpenes can be oxydized to form terpenoids which Confair: