Lipids - Group 1 PDF

BIOCHEMISTRY CHAPTER 4 WHAT ARE LIPIDS? STRUCTURE, AND PROPERTIES FUNCTIONS At the end of this module, the students should be able to: define lipids and describe their primary functions in biological systems; identify and explain the properties of lipids—including solubility,...

BIOCHEMISTRY CHAPTER 4 WHAT ARE LIPIDS? STRUCTURE, AND PROPERTIES FUNCTIONS At the end of this module, the students should be able to: define lipids and describe their primary functions in biological systems; identify and explain the properties of lipids—including solubility, consistency, hydrolysis, hydrogenation, emulsification, rancidity — hydrolytic and oxidative, and lipid peroxidation in vivo; explain the structure, classification, and biological significance of fatty acids, including the importance of omega fatty acids and chain lengths; classify lipids based on chemical structure, polarity, and charge, providing examples and brief descriptions; describe biologically significant lipids, such as triacylglycerols, phospholipids, glycolipids, lipoproteins, and steroids, including their structure and functions; and explain amphipathic lipids and discuss their role in membrane structures and emulsions, as well as their orientation in bilayers and liposomes. LIPIDS Greek word ‘lipos’ means fat. The term lipid was first used by a German biochemist ‘Bloor’ in 1943. Lipids are heterogenous group of compound related to fatty acid, fats, oils, waxes and other related compounds. Lipids are insoluble in water and soluble in organic solvent such as benzene, ether, chloroform, acetone etc. They yield fatty acids upon hydrolysis which are utilized by living organisms. Unlike the polysaccharides, proteins and nucleic acids, lipids are not polymers. (2024). App.goo.gl. https://images.app.goo.gl/BvAsMxVhpmqXDSst6 STRUCTURE OF LIPIDS The structure is typically made of a glycerolbackbone, 2 fatty acid tails (hydrophobic), and a phosphate group (hydrophilic). The hydrophilic part faces outward and the hydrophobic part faces inward. This arrangement Hanaumi, J. (2020, February 14). What Are Lipids? - Definition, Structure & Classification Of Lipids. Pinterest. https://pin.it/45S9qvalw helps monitor which molecules can enter and exit the cell. FUNCTIONS OF LIPIDS 1. Lipids protect the internal organs, serve as insulating materials and give shape and smooth appearance to the body. 2. They are the concentrated fuel reserve of the body Lipids. (2021). Physiopedia. https://www.physio-pedia.com/Lipids#/media/File:AdiposeTissue.png (triacylglycerols). 3. They serve as a source of fat-soluble vitamins (A, D, E and K). 4. Lipids are the constituents of membrane structure and regulate the membrane permeability (phospholipids and cholesterol). 5. Lipids are important as cellular metabolic regulators (steroid hormones and prostaglandins). Dawson, B. (2021, May 23). What Are Fat Soluble Vitamins?4 of The Most Vital Vitamins for The Body. Nutravita. https://www.nutravita.co.uk/blogs/news/what-are-fat-soluble-vitamins-4-of-the-most-vital-vitamins-for-the-body  PROPERTIES OF LIPIDS SOLUBILITY CONSISTENCY Lipids are hydrophobic, meaning they Lipids' consistency depends on fatty acid are insoluble in water but soluble in composition: fats are solid, oils are liquid. organic solvents like chloroform, Saturation, chain length, and double benzene, and ethanol. Short-chain fatty bonds affect consistency—more acids are more soluble than long-chain saturation and longer chains make lipids ones. more solid while unsaturated and shorter chains make lipids liquid. HYDROLYSIS HYDROGENATION Hydrolysis breaks lipids into glycerol and Hydrogenation adds hydrogen to unsaturated fats, fatty acids using water, aided by enzymes increasing saturation to extend shelf life and raise (lipases) or acidic/alkaline conditions. It's melting point. It can produce trans fats, which have essential for digestion and metabolism. negative health effects.  EMULSIFICATION OF LIPIDS RANCIDITY OF LIPIDS Emulsification is the process of breaking down Rancidity is the process by which fats and oils break large fat droplets into smaller, more down, causing unpleasant flavors, odors, and texture manageable particles, allowing fats to mix with changes. water. This is essential for digestion, as it increases the surface area of fats, making them It has TWO TYPES: more accessible to digestive enzymes like lipases. In the body, bile salts act as natural emulsifiers, Hydrolytic Rancidity: Caused by water breaking aiding in the absorption of fats within the small down triglycerides into free fatty acids and glycerol, intestine. often due to enzymes, resulting in off-flavors and smells. Oxidative Rancidity: Occurs when fats react with oxygen, forming free radicals and peroxides, accelerated by heat, light, and metals. Antioxidants like tocopherols (Vitamin E), hydroquinone, and synthetic preservatives (e.g., BHA, BHT) are added to prevent oxidative rancidity, extending shelf life and preserving food quality.  Lipid peroxidation is the oxidative degradation of lipids, leading to the formation of lipid peroxides and other reactive aldehydes. Initiated by free radicals, this process damages cell membranes, leading to cell dysfunction and is linked to chronic diseases such as cardiovascular Lipid diseases and cancer. The body combats this with antioxidant Peroxidation systems like glutathione and superoxide dismutase, while dietary antioxidants from fruits, vegetables, and in Vivo nuts also help protect against oxidative stress. The hydrolysis of triacylglycerols by alkali to produce Saponification glycerol and soaps in known as saponification. WHAT IS FATTY ACIDS? Fatty acids are carboxylic acids with hydrocarbon side chain. Fatty acids are essential for energy storage, cell membrane structure, and signaling pathways. Found in animal fats, plant oils, marine organisms, and microorganisms, fatty acids play crucial roles in hormone regulation, inflammation, and brain function. OCCURENCE Fatty acids mainly occur in the esterified form as major constituents of various lipids. They are also present as free (unesterified) fatty acids. Fatty acids of animal orgin are much simpler in structure in contrast to those of plant origin. Why most fatty acids are of even carbons? Most of the fatty acids that occur in natural lipids are of even carbons (usually 14- 20 carbon units). This is due to the fact that biosynthesis of fatty acids mainly occurs with the sequential addition of 2 carbon units. SATURATED FATTY ACIDS UNSATURATED FATTY ACIDS do not contain double bonds and is solid Unsaturated fatty acids contain one(monounsaturated fatty acids) or 2 or more double bonds (polyunsaturated fatty acids (PUFA)) and is liquid. Nomenclature of Saturated Fatty Acids Nomenclature of Unsaturated Fatty Acids 1. Identify the longest continuous chain 1. Identify the longest continuous chain 2. Number the chain from the carboxyl end 2. Number the chain from the carboxyl end 3. Use the suffix -anoic acid 3. Use the suffix -enoic acid (for monounsaturated) 4. Prefix indicates chain length or -a(di/tri/tetra)enoic acid (for polyunsaturated) 4. Prefix indicates chain length 5. Indicate double bond position 6. Specify cis or trans configuration  Geometric Isomerism in Unsaturated Fatty Acids (Cis configuration vs. Trans configuration) CIS CONFIGURATION TRANS CONFIGURATION 1. Hydrogen atoms on same side of 1. Hydrogen atoms on opposite sides of double bond double bond 2. Bent or "kinked" chain shape 2. Linear or "extended" chain shape 3. Increased membrane fluidity 3. Decreased membrane fluidity 4. More common in natural fatty acids 4. Less common in natural fatty acids OMEGA-3 FATTY ACIDS - Family: Polyunsaturated fatty acids (PUFAs) 1. Alpha-linolenic acid (ALA): -mostly found in chia seeds, flaxseeds, walnuts, canola oil 2. Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA): -mostly found in Fatty fish (salmon, sardines, mackerel), Shellfish (mussels, oysters), Algal oil supplements Biological effects: 1. Anti-inflammatory properties 2. Cardiovascular health support 3. Brain function and development 4. Immune system modulation Health benefits: 1. Reduced inflammation 2. Improved heart health 3. Supported brain function and development 4. Enhanced immune response Omega-6 Fatty Acids - Family:Polyunsaturated fatty acids (PUFAs) 1. Linoleic acid (LA): Mostly found in Vegetable oils (corn, soybean, sunflower), Nuts and seeds (sunflower, pumpkin, sesame), Meat and poultry 2. Arachidonic acid (AA): - Meat and poultry, Fish and seafood, Eggs and dairy products Biological effects: 1. Linoleic acid (LA): - Essential for skin and hair growth, Supports heart health, Anti-inflammatory effects 2. Arachidonic acid (AA): - Involved in brain function and development, Supports immune system and Pro-inflammatory effects (in excess) Health benefits: 1. Reduced inflammation 2. Improved heart health 3. Supported brain function and development 4. Enhanced immune response Based on length of Hydrocarbon Chains Depending on the length of carbon chains, fatty acids are categorized into 3 groups: Short chain with less than 6 carbons; Propionic Acid (Propanoic Acid) Propionic Acid (Propanoic Acid) Butyric Acid (Butanoic Acid) Valeric Acid (Pentanoic Acid) Caproic Acid (Hexanoic Acid) Medium chain with 8 to 14 carbons ; and Caprylic Acid (Octanoic Acid) Capric Acid (Decanoic Acid) Caprylic Acid (Octanoic Acid) Lauric Acid (Dodecanoic Acid) Myristic Acid (Tetradecanoic Acid) Long chain with 16 to 24 carbons. Palmitic Acid (Hexadecanoic Acid) Lignoceric Acid (Tetracosanoic Acid) Palmitoleic Acid (cis-9-Hexadecenoic Acid) Palmitoleic Acid (cis-9-Hexadecenoic Acid) Shorthand Representation of Fatty Acids Example. Palmitoleic Acid (16:1;9)  Based on Requirements Nonessential Fatty Acids Fatty acids that can be synthesized by the body. Saturated fatty acids (SFAs) and oleic acid, the primary monounsaturated fatty acid in our diet. examples of nonessential fatty acids. Lauric, myristic, and palmitic acids make up the majority of saturated fatty acids. Essential Fatty Acids Fatty acids that the body cannot synthesize and must be obtained from food. They fall into two categories—omega-3 and omega-6. The 3 and 6 refer to the position of the first carbon double bond and the omega refers to the methyl end of the chain. Omega-3 and omega-6 fatty acids are precursors to important compounds called eicosanoids. Eicosanoids are powerful hormones that control many other hormones and important body functions, such as the central nervous system and the immune system Deficiency of Essential Fatty Acid Essential fatty acid (EFA) deficiency can lead to dry, scaly skin, hair loss, poor wound healing, growth failure, and increased metabolic rate. It may contribute to cardiovascular disease due to chronic inflammation.  CLASSIFICATIONS OF LIPIDS (Chemical Structure and Composition) SIMPLE LIPIDS Esters of fatty acids with alcohols FATS AND OILS WAXES These esters of fatty acids with Esters of fatty acids (usually long chain) glycerol (1, 2, 3- Propanetriol) with alcohols other than glycerol. These alcohols may be aliphatic or alicyclic.  COMPLEX (COMPOUND) LIPIDS esters of fatty acids with alcohols containing additional groups such as phosphate, nitrogenous base,carbohydrate, protein etc. PHOSPHOLIPIDS GLYCOLIPID Contains fatty acids, alcohol, nitrogenous Contains fatty acids, alcohol, base, and phosphate group. nitrogenous base, and carbohydrates TWO TYPES: TYPES Glycosphingolipids Glycerol- Glyceroglycolipids phosphate Sphingo- phosphate  COMPLEX (COMPOUND) LIPIDS OTHERCOMPLEX LIPOPROTEIN SULFOLIPID Lipoproteins are round particles made of lipids characterized by the presence of a fat (lipids) and proteins that travel in your sulfate group (SO4) attached to a lipid bloodstream to cells throughout your molecule. body. AMINOLIPID lipids that contain amino groups (a group of atoms that includes nitrogen) in their structure. LIPOPOLYSACCHARIDES large molecu les that are a key component of the outer membrane of Gram-negative bacteria:  DERIVED LIPIDS substances that come from breaking down other types of lipids (fats and oils). When lipids are hydrolyzed (a process that involves breaking chemical bonds by adding water), they can be converted into simpler compounds. GLYCEROL AND OTHER ALCOHOLS STEROID HORMONES acts as a backbone for many lipids. These hormones are derived from cholesterol FATTY ACIDS and have a unique, four-ring structure long chains of carbon atoms with a carboxyl group at one end. They are HYDROCARBONS essential for building many types of lipids These are molecules made up of only carbon MONO- AND DIACYLGLYCEROLS and hydrogen atoms. They are like the basic Monoglycerides have one fatty acid building blocks for many lipids attached to glycerol, while diglycerides KETONE BODIES have two fatty acids These are substances produced when the body breaks down fat for energy, especially LIPID SOLUBLE VITAMINS during periods of fasting or low carbohydrate lipid soluble vitamins are derived lipids because they are formed from lipids intake through hydrolysis  Miscellaneous Lipids are a diverse group of compounds with lipid-like properties but do not belong to the main lipid classes (such as triglycerides or phospholipids). Examples includes Carotenoids, Squalene, Terpenes Characteristics Functions Hydrophobic: They are non-polar -Help protect cells from oxidative damage. and water-insoluble, like other lipids. -Used in waxes and protective coatings in Diverse Structures: Include varied plants and animals. structures, from linear chains to -Serve as building blocks for vitamins, complex ringed compounds. hormones, and other molecules.  Polar Non polar Different electronegativities Similar or identical Soluble in polar solvents electronegativities Stronger (dipole-dipole, Soluble in nonpolar solvents hydrogen bonding) Weaker (London dispersion forces)  NEUTRAL LIPIDS Neutral lipids, such as mono-, di-, and triacylglycerols, cholesterol, and cholesteryl esters, are uncharged, non- polar, and hydrophobic. They serve for energy storage and protection. FATS AND OILS formed by the esterification of three fatty acids SQUALENE with glycerol. hydrocarbon, with six isoprene units linked in a branched chain. WAXES Made from long-chain fatty acids. Long-chain fatty acid (e.g., C14 to C36) Long-chain alcohol (e.g.,C12 to C32) PENTACOSANE linear, unbranched structure CHOLESTEROL ESTERS (C25H52) Cholesterol Backbone: A rigid, multi-ring structure with no polar groups after esterification. Fatty Acid Chain: This nonpolar tail further increases the hydrophobic nature of the molecule.  POLAR (CHARGED) LIPIDS have hydrophilic regions and are essential for cellular structure and signaling. Lecithin (Phosphatidylcholine) - Complex lipid Cephalin (Phosphatidylethanolamine) - Complex lipid consists of a glycerol backbone, a choline head group, fatty acid chains, and a phosphate group. Cephalin is like lecithin but has an ethanolamine head group instead of choline.  POLAR (CHARGED) LIPIDS have hydrophilic regions and are essential for cellular structure and signaling. Sphingomyelin Gangliosides a complex lipid with a sphingosine backbone, a are glycosphingolipids with a sphingosine fatty acid chain, a phosphate group, and either a backbone, one fatty acid chain, and a complex choline or ethanolamine head group. oligosaccharide that includes one or more sialic acid residues.  POLAR (CHARGED) LIPIDS have hydrophilic regions and are essential for cellular structure and signaling. Cerebrosides are complex lipids with a sphingosine backbone, a fatty acid chain, and a single sugar unit (glucose or galactose), but they do not contain a phosphate group or choline/ethanolamine head group.  TRIACYLGLYCEROLS Triacylglycerols (formerly triglycerides) commonly known as neutral fats. Esters of glycerol with fatty acids, found in fats and oils of plants and animals. Insoluble in water and nonpolar. Storage: Primarily stored in adipose tissue within adipocytes in subcutaneous tissue and around certain organs which serves as thermal insulator. Human Body: Fat reserve percentage (20% in men, 25% in women), enough to sustain energy for 2– 3 months. Main Function: Energy reserve in animals; insulation and protection. Note: Triacylglycerols are not the structural components of biological membranes.  STRUCTURES OF ACYLGLYCEROLS Monoacylglycerols, diacylglycerols and triacylglycerols, respectively consisting of one, two and three molecules of fatty acids esterified to a molecule of glycerol, are known. Mixed triacylglycerols Simple triacylglycerols more common contain the same type They contain 2 or 3 different types of fatty acid residues. of fatty acid residue at In general, fatty acid attached to C1 is saturated, that attached to C2 is all the three carbons. unsaturated while that on C3 can be either. e.g., tristearoyl glycerol or tristearin. Triacylglycerols of plants, in general, have higher content of unsaturated fatty acids compared to that of animals.  PHOSPHOLIPIDS FUNCTIONS These are complex or compound lipids containing Phospholipids form membranes with proteins, regulating phosphoric acid, in addition to fatty acids, permeability and controlling substance movement. nitrogenous base and alcohol. In mitochondria, phospholipids maintain electron transport chain Major lipid constituents of cell membranes structure for cellular respiration. Amphipathic in nature like fatty acids. Phospholipids aid in the absorption of dietary fats in the intestine. They are essential for synthesizing lipoproteins, which transport lipids in the body. Phospholipids help remove excess cholesterol from the body. Phospholipids act as surfactants in the lungs, reducing surface tension; lack of surfactant can cause respiratory distress in infants. Cephalins are involved in blood clotting processes. Phosphatidylinositol generates second messengers that aid in hormone signaling. Classified on the basis of the type of alcohol: (1) Glycerophospholipids (or phosphoglycerides) (2) Sphingophospholipids (or sphingomyelins) The alcohol present is glycerol. The alcohol present is sphingosine. Ex. Phosphatidic acid Ex. Sphingomyelins  GLYCEROPHOSPHOLIPIDS Glycerophospholipids are the major lipids that occur in biological membranes. They consist of glycerol 3- phosphate esterified at its C1 and C2 with fatty acids. Usually, C1 contains a saturated fatty acid while C2 contains an unsaturated fatty acid. PHOSPHATIDIC ACID LECITHIN CEPHALIN The simplest form of phospholipid; not Phosphatidylcholine, also known as Phosphatidylethanolamine are found in high concentrations in tissues. lecithin (from the Greek - lecithos, phospholipids that contain meaning egg yolk) ethanolamine as their nitrogenous an intermediate in the synthesis of both is the most abundant group of base. triacylglycerols and phospholipids. phospholipids in cell membranes. The main difference between lecithin Other glycerophospholipids, which contain It is a type of phosphatidic acid with and cephalin lies in the base used: various nitrogenous bases or other choline as its base. lecithin contains choline, while cephalin groups, are considered derivatives of contains ethanolamine. Phosphatidylcholines serve as the phosphatidic acid. storage form of choline in the body. TYPES OF LIPOPROTEIN 1. Chylomicrons Structure: Largest lipoproteins, with high triglyceride content and low protein. Occurrence: Formed in the intestines after a meal to transport dietary fats. 2. VLDL (Very Low-Density Lipoproteins) Structure: Contains high triglyceride levels with moderate protein. Occurrence: Produced by the liver to transport triglycerides to tissues. 3. IDL (Intermediate-Density Lipoprotein).Structure:Intermediate density with reduced triglycerides, formed from VLDL. Occurrence: Occurs in the bloodstream as VLDL loses triglycerides. 4. LDL (Low-Density Lipoprotein) Structure: High cholesterol and low protein, smaller than VLDL. Occurrence: Formed from IDL in the blood; delivers cholesterol to cells. 5. HDL (High-Density Lipoprotein) Structure: Small, dense, high in protein with lower fat content. Occurrence: Produced by the liver and intestines, circulates to collect excess cholesterol.  STEROIDS and STEROLS Steroids are lipids with a four-ring structure (three cyclohexane rings and one cyclopentane). They play key roles in maintaining cell membrane integrity and regulating hormonal signaling. GONANE - "Steroid Nucleus" Sterols are lipids with a steroid nucleus, a hydroxyl group at carbon 3, and a side chain at carbon 17. They are key membrane components in eukaryotes, helping maintain membrane rigidity, fluidity, and permeability.  CHOLESTEROLS ERGOSTEROL Cholesterol is found in all animal tissues and Ergosterol is found in the cell membranes of fungi some fungi, produced by nucleated animal cells. and protozoa, serving similar functions as It is a structural component of cell membranes, cholesterol in animal cells. It plays a crucial crucial for membrane stability and fluidity, and a structural role, forms lipid rafts, and regulates precursor for steroid hormones, vitamin D, and growth. Ergosterol is a precursor to vitamin D2 and bile acids. Cholesterol (C27H46O) has a is targeted by antifungal drugs. Its structure hydroxyl group at C3, a double bond between consists of ergostane with double bonds at the 5,6-, C5 and C6, and an 8-carbon side chain at C17, 7,8-, and 22,23-positions, and a 3β-hydroxy group, making it weakly amphiphilic. classifying it as a 3β-sterol and phytosterol.  VITAMIN D CORTISTEROIDS Vitamin D2 has a double bond between carbon atoms 22 and 23 and a methyl group (-CH3) at carbon 24. It regulates calcium and phosphorus levels, supporting bone health and immune function. Vitamin D2 is derived from ergosterol in yeast and fungi when exposed to UV light. Cortisol has a steroid backbone with three six- membered rings (A, B, and C) and one five-membered ring (D). Hydroxyl groups at C11 and C17, a carbonyl Vitamin D3 has a single bond between carbon atoms 22 and group at C3, and a methyl group at C21 are key to its 23 and lacks the methyl group at carbon 24, distinguishing it structure and biological activity. Cortisol regulates from Vitamin D2. It regulates calcium and phosphorus, promotes bone health, and supports the immune system, stress response, metabolism, inflammation, blood making it more potent than Vitamin D2. Vitamin D3 is pressure, blood sugar, and the sleep-wake cycle. It is produced naturally in the skin from sunlight and is found in produced by the adrenal glands, located on top of the animal products like fatty fish and egg yolks. kidneys.  SEX HORMONES BILE ACIDS CHOLIC ACIDS Sex hormones, like estrogens (e.g., estradiol) and Bile Acid like Cholic acid is primarily found in the liver, androgens (e.g., testosterone), are steroid gallbladder, and intestines, playing a key role in fat hormones produced primarily by the gonads digestion and absorption. It has a four-ring steroid (ovaries in females, testes in males). They share a backbone typical of bile acids, with three hydroxyl groups common steroid backbone with four fused rings, at C3, C7, and C12 for water solubility. A carboxylic acid and the presence and position of functional groups group at one end aids digestion, while a long like hydroxyl, carbonyl, and methyl groups hydrocarbon side chain contributes to its amphipathic determine their biological activity. These hormones nature. Bile acids are crucial for fat digestion, cholesterol regulate sexual development, reproduction, and regulation, digestive health, and act as signaling molecules, supporting overall metabolic health. secondary sex characteristics.  SPHINGOPHOSPHOLIPIDS are phospholipids with a sphingosine backbone, playing key roles in cell signaling and membrane structure. sphingomyelin ceramide-1-phosphate Sphingomyelin is a sphingophospholipid with a Ceramide-1-phosphate has a ceramide backbone and a sphingosine backbone, fatty acid chain, and phosphate group, with the structural formula CH₃- phosphocholine headgroup. It is found in cell (CH₂)n-CH=CH-(CH₂)m-CH(OH)-CH(NH-CO-R)-CH₂- membranes, the myelin sheath, brain tissue, nerve O-PO₃H₂. It differs in its ceramide backbone, phosphate cells, red blood cells, and blood plasma lipoproteins. group, and hydroxyl (OH) and amine (NH₂) groups. Its structural formula is CH3-(CH2)12-CH=CH- Ceramide-1-phosphate is found in cell membranes, CH(OH)-CH(NH-CO-R)-CH2-O-PO3-CH2-CH2- brain tissue, nerve cells, and blood plasma, playing N(CH3)3+. roles in cell growth, apoptosis, and immune response. Structure o f Sphingomyelin Biosynthesis o f ceramide-1- phosphate  SPHINGOPHOSPHOLIPIDS are phospholipids with a sphingosine backbone, playing key roles in cell signaling and membrane structure. sphingomyelin ceramide-1-phosphate Sphingomyelin is a sphingophospholipid with a Ceramide-1-phosphate has a ceramide backbone and a sphingosine backbone, fatty acid chain, and phosphate group, with the structural formula CH₃- phosphocholine headgroup. It is found in cell (CH₂)n-CH=CH-(CH₂)m-CH(OH)-CH(NH-CO-R)-CH₂- membranes, the myelin sheath, brain tissue, nerve O-PO₃H₂. It differs in its ceramide backbone, phosphate cells, red blood cells, and blood plasma lipoproteins. group, and hydroxyl (OH) and amine (NH₂) groups. Its structural formula is CH3-(CH2)12-CH=CH- Ceramide-1-phosphate is found in cell membranes, CH(OH)-CH(NH-CO-R)-CH2-O-PO3-CH2-CH2- brain tissue, nerve cells, and blood plasma, playing N(CH3)3+. roles in cell growth, apoptosis, and immune response. Structure o f Sphingomyelin Biosynthesis o f ceramide-1- phosphate  GLYCOLIPIDS Glycolipids have a structure consisting of a mono- or oligosaccharide group attached to a sphingolipid or glycerol backbone, with one or two fatty acids. They form glycosphingolipids and glycoglycerolipids. The lipid tail’s hydrophobic nature anchors glycolipids to the plasma membrane's lipid bilayer. CEREBROSIDES Structure: Ceramide + monosaccharide (galactose or glucose) Types: Galactocerebroside (GalCer), Glucocerebroside (GluCer) Occurrence: Found in cell membranes, especially in the nervous system, brain tissue, and red blood cells. Key Difference: Differ in sugar residue (galactose or glucose) and fatty acid chain length/saturation.  GANGLIOSIDES Structure: Ceramide + oligosaccharide + NANA (sialic acid) Types: GM1, GM2, GM3, GD1a, GD1b, GT1b Occurrence: Found in animal cell membranes, brain, and nervous system. Function: Regulate cell signaling, adhesion, growth, and neurodevelopment. Key Difference: Contain sialic acid (NANA), influencing the structure and function. GLOBOSIDES Structure: Ceramide + oligosaccharide Types: Globotriaosylceramide (Gb3), Globotetraosylceramide (Gb4) Occurrence: Found in eukaryotes, particularly in cell membranes and mammals. Function: Regulate cellular signaling, apoptosis, and blood- type determination. Key Difference: Differ in the number of sugar units (Gb3, Gb4). AMPHIPATHIC LIPIDS Overview of Structure, Examples, and Clinical Relevance What are Amphipathic Lipids? Amphipathic lipids are molecules that contain both hydrophobic (water-repelling) and hydrophilic (water-attracting) regions. This unique structure allows them to form bilayers and micelles, making them essential components of cell membranes and aiding in lipid transport and digestion. Example Of Amphipathic Lipids Fatty acids Phospholipids Sphingolipids Bile salts cholesterol Clinical Relevance Membrane Structure: Amphipathic lipids (e.g., phospholipids) form cell membranes; defects can lead to diseases like cystic fibrosis. Drug Delivery: Used in liposomes for targeted drug delivery, especially in cancer treatments (e.g., Doxil). Cholesterol and Cardiovascular Disease: Cholesterol imbalance (HDL/LDL) contributes to atherosclerosis, increasing risk of heart attack and stroke. Bile Acids: Critical for fat digestion; defects cause gallstones and bile acid malabsorption. Neurodegenerative Diseases: Sphingolipids maintain myelin integrity; abnormalities lead to multiple sclerosis and Fabry disease. Inflammation: Amphipathic lipids involved in immune signaling; imbalances contribute to conditions like rheumatoid arthritis and asthma LIPOSOMES They are produced when amphipathic lipids in aqueous medium are subjected to sonification. They have intermittent aqueous phases in the lipid bilayer. Liposomes, in combination with tissue specific antigens, are used as carriers of drugs to target tissues. EMULSION These are produced when nonpolar lipids (e.g. triacylglycerols) are mixed with water. The particles are larger in size and stabilized by emulsifying agents (usually amphipathic lipids), such as bile salts and phospholipids.  THE DIFFERENCE BETWEEN SOAPS DETERGENT Soaps are sodium or potassium salts of fatty Detergents are synthetic cleansing agents e.g. acids. They are produced by saponification of fats. sodium lauryl sulfate. Detergents are superior in Sodium soaps are hard that result in bar soaps. their cleansing action compared to soaps, and are Soaps serve as cleansing agents since they can used in washing clothes, and in toothpaste. emulsify oils and remove the dirt. References: 2024). App.goo.gl. https://images.app.goo.gl/BvAsMxVhpmqXDSst6 Hanaumi, J. (2020, February 14). What Are Lipids? - Definition, Structure & Classification Of Lipids. Pinterest. https://pin.it/45S9qvalw Lipids. (2021). Physiopedia. https://www.physio-pedia.com/Lipids#/media/File:AdiposeTissue.png Dawson, B. (2021, May 23). What Are Fat Soluble Vitamins? 4 of The Most Vital Vitamins for The Body. Nutravita.https://www.nutravita.co.uk/blogs/news/what-are-fat-soluble-vitamins-4-of-the-most-vital-vitamins-for-the-body Cooper, G. M. (2024). Figure 2.49, Permeability of phospholipid bilayers. 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