Lipids PDF

What are your preconceived notions about lipids or fats? WHAT IS LIPIDS ? TERMS TO PONDER 1. COVALENT BOND - is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs...

What are your preconceived notions about lipids or fats? WHAT IS LIPIDS ? TERMS TO PONDER 1. COVALENT BOND - is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding. 2. COVALENT COMPOUNDS is made when two or more nonmetal atoms bond by sharing valence electrons. The shared valence electrons between two nonmetal atoms is called a covalent bond. Covalent bonds are formed when two atoms begin sharing electrons. The electrons are attracted to the positively charged nuclei of the atoms. 3. A polar covalent bond Exists when atoms with different electronegativities share electrons in a covalent bond.  A polar covalent bond is a bond in which the electron pair is shared unequally between the two bonded atoms. Polar bonds are caused by differences in electronegativity. ex. H2O ,HFl ,NH3 , SO2 4. A non-polar covalent bond Is a bond in which the electron pair is shared equally between the two bonded atoms. Exist between two nonmetals which have little to no difference in the electronegativity of the two atoms ex. CO2, O2 , N2 , O3 Lipids Lipids Definition – are a group of heterogeneous organic compounds which are soluble in non-polar solvents , naturally occur in most plants, animals, and microorganisms. Hydrophobic, meaning water hating.They are water insoluble. Non-polar molecules while water is polar molecule, so there is no way for water to attach to a lipid molecule. Instead, the non-polar lipids will bind to themselves, which is why oils and fats form droplets on the surface of water Lipids are organic molecules consisting of carbon, hydrogen, and oxygen atoms and serve as : energy storage, structural support cell membrane composition in living organisms. insulators - assisting in the maintenance of body temperature facilitate the absorption of fat-soluble vitamins. Lipids, as a class of compounds, are Insoluble in water but are soluble in other organic solvents. Examples of such solvents include : 1.Acetone 2. Ether 3.Alcohol 4. Chloroform 5. Benzene. Lipids are Hydrophobic, meaning water hating.They are water insoluble. Lipids are non-polar molecules while water is polar molecule, so there is no way for water to attach to a lipid molecule. Instead, the non-polar lipids will bind to themselves, which is why oils and fats form droplets on the surface of water. Diverse in both their respective structures and functions. These diverse compounds that make up the lipid family are so grouped because they are insoluble in water. They are also soluble in other organic solvents such as ether, acetone, and other lipids. Lipids serve a variety of important functions in living organisms. They act as chemical messengers, serve as valuable energy sources, provide insulation, and are the main components of membranes. Fatty acids are the building blocks of the fat in our bodies and in the food we eat. Fatty acids (FAs) are integral building blocks of lipids During digestion, the body breaks down fats into fatty acids, which can then be absorbed into the blood. Fatty acid molecules are usually joined together in groups of three, forming a molecule called a triglyceride. STRUCTURAL FORMULA : 1. PHOSPHOLIPIDS AND FATTY ACID  CLASSIFICATION OF LIPIDS Examples of Lipids Lipid examples are Ghee, Butter, Oil, Cheese, Cholesterol, waxes, etc. All these compounds have one thing in common i.e., they are insoluble in water and are soluble in organic solvents. Examples of lipids are as follows: 1.Triglycerides: Found in fats and oils, these store energy in cells. What are triglycerides? Triglycerides are a type of fat (lipid) found in your blood. When you eat, your body converts any calories it doesn't need to use right away into triglycerides. The triglycerides are stored in your fat cells. Later, hormones release triglycerides for energy between meals. If you regularly eat more calories than you burn, particularly from high-carbohydrate foods, you may have high triglycerides (hypertriglyceridemia). What's the difference between triglycerides and cholesterol? Triglycerides and cholesterol are different types of lipids that circulate in your blood: Triglycerides store unused calories and provide your body with energy. Cholesterol is used to build cells and certain hormones. 2.Phospholipids: Key components of cell membranes, forming lipid bilayers. Both TAG and phosphoacylglycerol structures are almost the same just, phosphoacylglycerol-OH and phosphoric acid are attached with an ester bond and form the phosphatidic acid. 3.Steroids: Include cholesterol, a membrane component, and steroid hormones. 4. Waxes: Provide waterproofing in plants, animals, and microorganisms. Waxes are usually saturated with long-chain monohydric alcohols. They are the simple esters of fatty acids. Here are some examples: 1.Beeswax: Beeswax includes fatty acids and some free alcohol. 2.Carnauba wax: It is a hard wax used on cars and boats. 3.Spermaceti: it consists of cetyl palmitate. Used for pharmaceuticals. 5.Glycolipids: Contain carbohydrates and are important in cell recognition. 6. Sphingolipids: A diverse group of lipids involved in signaling and structure. 7. Lipoproteins: Complexes of lipids and proteins, transport lipids in the bloodstream. 8. Eicosanoids: Signaling molecules derived from fatty acids, regulate inflammation. 9. Isoprenoids: Include vitamins (e.g., vitamin A) and carotenoids, with various functions 3 Main Types of Lipids Lipids subunits are – Glycerol and Fatty acids. Lipids are mainly classified into three types. They are simple, complex, and derived lipids. 1. Simple Lipids: Simple lipids are triglycerides, esters of fatty acids, and wax esters. The hydrolysis of these lipids gives glycerol and fatty acids. Simple Lipids Simple lipids are triglycerides, esters of fatty acids, and wax esters. The hydrolysis of these lipids gives glycerol and fatty acids. Simple lipids are classified into Triglycerides and Waxes. 1. Fats: Fatty acids join with glycerol via ester bonds.  2. Waxes: Fatty acid jig with a large molecular weight monohydric alcohol with an ester bond. Triglycerides Triglycerides are the most common type of simple lipids. They consist of glycerol molecules linked to three fatty acid chains through ester bonds. Triglycerides are found in adipose tissue (body fat) and serve as a long-term energy reserve. They are the constituents of fats and oils. Lipids that are solid at room temperature are fats, and lipids that are liquid at room temperature are oils. Glycerol It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in those lipids known as glycerides. It is a simple polyol compound. 2. Complex (Compound) Lipids:  Complex or compound lipids are the esters of fatty acids with groups along with alcohol and fatty acids. Examples are Phospholipids and Glycolipids. Complex lipids are a type of lipids that have more complex structures compared to simple lipids (triglycerides and waxes). They contain additional molecules, such as phosphates, carbohydrates, proteins, fatty acids and glycerol. Complex lipids are involved in various biological functions, including cell structure, energy storage, and cell signaling. Examples of complex lipids are Phospholipids and glycolipids. Phospholipids Phospholipids are constituents of cellular membranes. An ester is formed when a hydroxyl reacts with a carboxylic acid and loses H2O. Phospholipids, also known as phosphatides, are classes of lipids whose molecule has a hydrophilic head and two hydrophobic tails. A head containing a phosphate group and tails derived from fatty acids joined by a glycerol molecule. They serve as emulsifiers. There are two types of phospholipids:  Glycerophospholipids: Glycerophospholipids are the class of phospholipids containing glycerol as alcohol, two fatty acids, and phosphate. It is the most abundant lipid in the cell membrane. Sphingophospholipids: Sphingophospholipids are the class of phospholipids containing sphingosine as alcohol. It produces ceramide by an amide linkage to a fatty acid. Ceramide is an important component of skin. It acts as a second messenger to regulate programmed cell death. Glycolipid It is a structural lipid, an essential part of the cell membrane. They are lipids with a carbohydrate attached by a glycosidic bond. They act as receptors at the surface of the red blood cell. It helps in the determination of an individual blood group. It has an important role in maintaining the stability of the cell membrane. It kills pathogens to help the immune system of the body. Cerebrosides and Gangliosides are the two types of Glycolipids. Saturated Fatty Acids It consists of single C-C single bonds. These molecules fit closely together in a regular pattern and have strong attractions between fatty acid chains. These fatty acids have high melting points, which makes them solid at room temperature. Examples of saturated fatty acids are palmitic acid and stearic acid. Unsaturated Fatty Acids Unsaturated fatty acids are fatty acids that consist of one or more C=C double bonds. An unsaturated fatty acid is divided into two types. 1. Mono polyunsaturated fatty acids: Example: oleic acid.  2. Polyunsaturated fatty acids: Example: linoleic acid. Role of Fats Fats play an essential role in the body, including: Fats help our body by absorbing and transporting important fat-soluble vitamins. They are an important source of essential fatty acids. They insulate and protect our vital body organs. Fats produce energy in the form of carbohydrates. Fats are the structural component of cells. They help the body produce and regulate hormones. Fats support cell growth. They maintain our core temperature. Maintains blood pressure and cholesterol. 3. Derived lipids: Derived lipids are the hydrolyzed compounds of simple and complex lipids. Examples are fatty acids, steroids, fatty aldehydes, ketone bodies, lipid-soluble vitamins, and hormones. Steroids Steroids are found in the cell membrane and have fused ring structures. Many steroids have -OH functional groups, they are also hydrophobic and insoluble in water. All the steroids have 4 linked carbon rings and most of them have a short tail. Steroids also act as hormones in the body. Sterols Sterols are solid steroid alcohols that are widely present in plants and animals such as cholesterol and ergosterol. They are the subgroup of steroids, which naturally occur in most eukaryotes. They are found in animal products. They are used to make bile for digestion in the body. Sterols can have greater than half of the membrane lipid content in cells and they are known to alter membrane structure and fluidity. Carotenoids Carotenoids are lipid-soluble compounds. They are pigments that are mainly responsible for the yellow and red colors of plant and animal products. Carotenoids consist of carotenes and xanthophylls. A class of hydrocarbons is carotenes and its oxygenated derivatives are xanthophylls. They give color to many fruits and vegetables. They have antioxidant and anti-inflammatory properties for humans. Carotenoids are important for the health of the human eye. Major lipid groups : 1. Fats 2. Phospholipids 3. Steroids 4. Waxes. WHAT ARE DIFFERENT TYPES OF LIPIDS ? 1. Waxes Waxes are composed of alcohol and fatty acid. Plants often have wax coatings that help them to conserve water. 2. Steroids Human sex hormones, like testosterone and estrogen, are classed as steroids. Steroids most often have a four-fused ring structure ex. Cholesterol, Bile Salts. 3. Phospholipids Phospholipids have four major components: 1.Fatty Acids, 2.a Glycerol component, and both 3. a Phosphate group and 4. a Polar molecule. 4. Glycerol Fats have glycerol in addition to three fatty acids. The structure of the fatty acids determines whether or not the fat is considered saturated or unsaturated. 5. Prostaglandins Group of lipids with hormone-like actions that your body makes primarily at sites of tissue damage or infection. There are several different types of prostaglandins, and they play several essential roles in regulating bodily processes, including: Blood clot formation at the site of an injury. WHAT ARE THE PROPERTIES OF LIPIDS Lipids are a heterogeneous group of organic compounds that are insoluble in water and soluble in non-polar organic solvents. They have distinctive physical and chemical properties. General Physical Properties of Lipids Energy-rich organic molecules Soluble in non-polar solvents such as acetone, ether, chloroform, benzene, and alcohol Insoluble in water Either liquid or non-crystalline solid at room temperature Greasy in texture Hydrophobic or amphiphilic Devoid of ionic charges Present either in saturated or unsaturated structural form Stored in adipose tissues in the body Chemical Properties of Lipids Hydrolysis of triglycerols: Triglycerides, which are neutral lipids, react with water to form carboxylic acid and alcohol in a process known as hydrolysis. Hydrogenation: Unsaturated fats are converted into saturated fats by hydrogenation, which involves adding hydrogen atoms. The reaction with hydrogen breaks the double bonds present in unsaturated fats, producing saturated fats. Saponification: Saponification is a chemical reaction in which lipids, particularly triglycerides, react with alkalis such as sodium hydroxide (NaOH) or potassium hydroxide (KOH) to form soap or fatty acid salts of sodium or potassium, and glycerol. Halogenation: When unsaturated fatty acids come into contact with halogens, halogen atoms are added to the double bonds, resulting in de-colorization, in which the halogen solution loses its original color. Rancidity: Oxidation and hydrolysis of fats and oil are responsible for causing rancidity, in which the fat or oil develops a disagreeable odor. WHAT ARE THE FUNCTIONS OF LIPIDS ? 1.Energy Storage The excess energy from the food we eat is digested and incorporated into adipose tissue, or fat tissue. Most of the energy required by the human body is provided by carbohydrates and lipids; in fact, 30-70% of the energy used during rest comes from fat. As discussed previously, glucose is stored in the body as glycogen. While glycogen provides a ready source of energy, lipids primarily function as an energy reserve. Glycogen is quite bulky with heavy water content, thus the body cannot store too much for long. Fat is used for energy during exercise, especially after glycogen is depleted. Fats are packed together tightly without water and store far greater amounts of energy in a reduced space. A fat gram is densely concentrated with energy—it contains more than double the amount of energy than a gram of carbohydrate. Unlike other body cells that can store fat in limited supplies, fat cells are specialized for fat storage and are able to expand almost indefinitely in size. 2. Regulating and Signaling Lipids are part of the cell membrane structure which helps maintain cell membrane fluidity and flexibility. Triacylglycerols control the body’s internal climate with the goal of maintaining constant temperature. Those who don’t have enough fat in their bodies tend to feel cold sooner. Triacylglycerols also help the body produce and regulate hormones. For example, adipose tissue secretes the hormone leptin, which regulates appetite. In the reproductive system, fatty acids are required for proper reproductive health; women who lack proper amounts may stop menstruating and become infertile. Omega-3 and omega-6 essential fatty acids help regulate cholesterol and blood clotting and control inflammation in the joints, tissues, and bloodstream. Fats also play important functional roles in sustaining nerve impulse transmission, memory storage, and tissue structure. More specifically in the brain, lipids are focal to brain activity in structure and in function. They help form nerve cell membranes, insulate neurons, and facilitate the signaling of electrical impulses throughout the brain. 3. Insulating and Protecting Within the body there are two types of fat - visceral and subcutaneous. Visceral fat surrounds vital organs such as the heart, kidneys, and liver. Subcutaneous fat, or fat underneath the skin, insulates the body from extreme temperatures and helps keep the internal climate under control. It pads our hands and buttocks and prevents friction, as these areas frequently come in contact with hard surfaces. It also gives the body the extra padding required when engaging in physically demanding activities such as ice- or roller skating, horseback riding, or snowboarding. 4. Transporting Fat-soluble nutrients are important for good health and exhibit a variety of functions. Vitamins A, D, E, and K—the fat-soluble vitamins—are mainly found in foods containing fat. Fat-soluble nutrients require fat for effective absorption. These vitamins are best absorbed when combined with foods containing fat. Fats also increase the bioavailability of compounds known as phytochemicals, which are plant constituents such as lycopene (found in tomatoes) and beta-carotene (found in carrots). Phytochemicals are believed to promote health and well-being. As a result, eating tomatoes with olive oil or salad dressing will facilitate lycopene absorption. Other essential nutrients, such as essential fatty acids, are constituents of the fats themselves and serve as building blocks of a cell.