Lecture 2 Flashcards
Lipids are more related by their physical properties than their chemical properties true or false
Lipids are heterogeneous compounds cuz they give rise to many more compounds.
Some lipids can somehow exist in water but most don’t
Some lipids carry ionic charges but most don’t
Chloroform and organic solvents are hydrophobic
fatty acids can form esters when they react with alcohols, a process known as esterification. This reaction is typically facilitated by a catalyst, particularly in biological or industrial settings.
Waxes are monoacylycerols
Fats are triacylglycerol
Difference between peroxidation and rancidity
waxes are hydrophobic because they contain very long fatty acid chains (either saturated or unsaturated) or aliphatic chains. These chains are nonpolar, meaning they don’t interact well with water, which is polar. As the chains get longer, the molecule becomes more nonpolar and, therefore, more hydrophobic. This is why waxes are insoluble in water and serve as excellent protective coatings in nature (such as on plant leaves, animal feathers, etc.).
True
Yes, you’re absolutely correct! Hydrolysis is the process in which a bond is broken by the addition of water. Specifically, in the context of lipids, hydrolysis involves breaking the ester bond between a fatty acid and an alcohol (like glycerol). This reaction is essential for processes such as digestion and the breakdown of triglycerides.
Hydrolysis of Lipids (Ester Bonds):
• Bond to Break:
In lipids, ester bonds link fatty acids to alcohol molecules (like in triglycerides or phospholipids). For hydrolysis to occur, these ester bonds need to be broken, releasing fatty acids and alcohol (like glycerol).
• Enzymatic Reactions:
• Lipase is the enzyme typically involved in breaking down triglycerides into fatty acids and glycerol through hydrolysis. Lipases are essential for the digestion of dietary fats.
• Esterases are enzymes that also catalyze the hydrolysis of ester bonds, but they can work on a broader range of ester compounds (not just triglycerides).
Conditions for Hydrolysis:
• Water: Hydrolysis requires water as a reactant to break the ester bond.
• Enzymes (Lipases/Esterases): In biological systems, enzymes such as lipases (for lipids) and esterases (for other esters) are responsible for catalyzing these reactions under mild conditions. These enzymes lower the activation energy and increase the rate of reaction.
Summary:
• Hydrolysis of lipids involves breaking the ester bond between fatty acids and alcohols, typically catalyzed by lipases (for triglycerides) or esterases (for a variety of esters).
• Water is necessary for the reaction to occur, and enzymatic catalysis ensures this process is efficient, particularly in biological systems.
You’re right in recognizing the connection between peroxidation and rancidity, but there’s a key difference in their context and scope.
Peroxidation:
• Definition: Peroxidation is a chemical reaction involving the oxidation of lipids, typically unsaturated fatty acids, by reactive oxygen species (ROS). This reaction results in the formation of lipid peroxides, which can lead to cellular damage.
• Location: Peroxidation occurs primarily in the cell, where free radicals and ROS can attack lipids in cell membranes, causing oxidative stress and potentially leading to cell damage, inflammation, or dysfunction.
• Examples: Peroxidation is a key process in cell aging, neurodegenerative diseases, and cardiovascular diseases.
Rancidity:
• Definition: Rancidity refers to the spoilage of fats and oils, typically caused by the oxidation (peroxidation) of unsaturated fats, resulting in unpleasant odors and tastes. There are two main types of rancidity:
1. Oxidative rancidity (the one related to peroxidation)
2. Hydrolytic rancidity (involves the breakdown of triglycerides into free fatty acids by water).
• Location: Rancidity generally occurs outside the body, in foods containing fats and oils exposed to air, light, and heat, which leads to oxidation and the formation of off-flavors and odors.
Key Differences:
• Peroxidation is a biological or chemical process that happens inside cells, often causing damage to cell membranes and tissues.
• Rancidity is the spoilage of food or oils due to oxidation (peroxidation), causing undesirable changes in smell and taste.
Summary:
While peroxidation and rancidity both involve oxidation of lipids, peroxidation is a chemical reaction occurring within cells and can lead to damage, while rancidity refers to the spoilage of food due to oxidation, producing bad odors and tastes.
What are lipids?
They are related more by their chemical than by their physical properties.
True or false
False
Fat and oils structures
The lipids are a heterogeneous group of naturally occurring compounds; including fats, oils, steroids, waxes, and related compounds, that are related more by their physical than by their chemical properties.
State the different categories of lipids
Note that sugars are hydrophilic
Classification of lipids
1.Simple lipids: Esters of fatty acids with various alcohols.
A.Fats: Esters of fatty acids with glycerol. Oils are fats in the liquid state.
B. Waxes: Esters of fatty acids with higher molecular weight monohydric alcohols
2.Complex lipids: Esters of fatty acids containing groups in addition to an alcohol and a fatty acid. Complex lipids are lipids that contain not only fatty acids but also additional functional groups or prosthetic groups, such as phosphate groups, sugars, or proteins. These additional groups are often used to make the lipids more hydrophilic (water-loving), which helps them interact with the aqueous environment of the cell.
A.Phospholipids: Lipids containing, in addition to fatty acids and an alcohol, a phosphoric acid residue. They frequently have nitrogen-containing bases and other substituents, eg, in sycerophospholipids the acohol is glycerol and in sphing ophospho lipids the alcohol is
B.Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine, and carbohydrate.
C. Other complex lipids: Lipids such as sulfolipids and aminolipids. Lipoproteins may also be placed in this category.
Alright — let’s break it down very simply:
Bile salts are emulsifying agents because they help break big fat droplets into tiny droplets in the small intestine.
This makes it easier for enzymes (like lipase) to digest the fats.
Here’s how it works:
• Fats normally don’t mix well with water (they clump together).
• Bile salts have two sides:
• One side loves water (hydrophilic).
• One side loves fat (hydrophobic).
• So bile salts stick to fat droplets with their fat-loving side, and face the water with their water-loving side.
• This breaks the big fat into many small, tiny droplets suspended in water — this is called an emulsion.
In short:
Bile salts break fats into small pieces and keep them spread out, so fat-digesting enzymes can work better.
Would you like me to also draw this out in a simple step-by-step picture description (like: Step 1, Step 2, Step 3)? It’s easy to memorize that way!
1.Fatty acids- saturated and unsaturated
2.Glycerides-neutral glycerides and phosphoglycerides: Neutral glycerides, also known as neutral fats or triglycerides, are a type of lipid composed of glycerol and three fatty acids. These molecules are called “neutral” because they are nonpolar and do not carry a charge. They are the most common form of fat found in the human body and in many types of food.
Structure
• Glycerol Backbone: A three-carbon molecule with each carbon bearing a hydroxyl group (-OH). • Fatty Acids: Long hydrocarbon chains with a carboxyl group (-COOH) at one end. Each fatty acid forms an ester bond with one of the hydroxyl groups on glycerol.
Formation
The formation of a triglyceride involves an esterification reaction, where the hydroxyl groups of glycerol react with the carboxyl groups of three fatty acids, releasing three molecules of water. Glycerides, also known as acylglycerols, are esters formed from glycerol and fatty acids. Glycerides are different from glyco- which is related to sugar or carbs.
They are a major component of lipids in the body and in food. Glycerides are classified into three types based on the number of fatty acids attached to the glycerol molecule:
1. Monoglycerides: One fatty acid attached to glycerol. 2. Diglycerides: Two fatty acids attached to glycerol. 3. Triglycerides: Three fatty acids attached to glycerol.
Triglycerides are the most common form of glycerides and are the main constituents of body fat in humans and animals, as well as vegetable fat. They serve as an important energy source and are stored in adipose tissue. Glycerol is hydrophilic due to its three hydroxyl (–OH) groups. These hydroxyl groups are highly polar and can form hydrogen bonds with water molecules, making glycerol soluble in water.however, while glycerol is part of a molecule that can be hydrophobic overall, glycerol itself is hydrophilic. When a fatty acid combines with glycerol, the result is a glyceride. The process involves esterification, where the hydroxyl groups of glycerol react with the carboxyl groups of fatty acids, forming ester bonds. Glycerides are generally hydrophobic due to their structure.
Here’s why:
• Fatty Acids: The fatty acid chains in glycerides are long hydrocarbon chains, which are nonpolar and hydrophobic. This hydrophobic nature dominates the molecule’s overall properties. • Glycerol Backbone: While glycerol itself is hydrophilic due to its hydroxyl groups, the hydrophobic fatty acid chains reduce the overall hydrophilicity when attached.
Thus, glycerides are mostly hydrophobic, which makes them insoluble in water but soluble in nonpolar solvents. This property is important for their role in energy storage and forming lipid bilayers in cell membranes.
3.Non glyceride lipids-waxes,steroids,sphingolipids(sphingomyelins and Glycolipids): These lipids do not contain glycerol in their structure. Some key types of non-glycerine lipids include:
1. Fatty Acids: Simple lipid molecules consisting of a carboxyl group attached to a hydrocarbon chain. 2. Steroids: Characterized by a four-ring carbon structure, including cholesterol and steroid hormones. 3. Waxes: Esters of long-chain fatty acids with long-chain alcohols, providing protective coatings. 4. Terpenes: Composed of isoprene units, including essential oils and carotenoids. 5. Sphingolipids: Contain a sphingosine backbone and are important in cell membranes, particularly in the nervous system. 6. Glycolipids: Glycolipids are molecules that consist of a lipid tail and a sugar (or carbohydrate) group. Glycolipids can have either a glycerol backbone or a sphingosine backbone. glycolipids can indeed have glycerol if they are glycoglycerolipids. If they are glycosphingolipids(especially in the nervous system)I, they do not contain glycerol but instead have a sphingosine backbone. 7. Phospholipids: Contain a phosphate group and are essential components of cell membranes. The most common type is phosphatidylcholine. Categorization Clarification • Non-Glycerine Lipids: Phospholipids with a sphingosine backbone (sphingophospholipids) fall into this category since they do not contain glycerol. • Complex Lipids: Both glycerophospholipids and sphingophospholipids fall into this category because they contain additional groups like phosphate and nitrogenous bases, making them more complex than simple lipids.
Summary
• Glycerophospholipids: Complex lipids with a glycerol backbone. • Sphingophospholipids: Complex lipids with a sphingosine backbone, also considered non-glycerine lipids.
So, phospholipids can be classified based on their complexity (as complex lipids) and their backbone structure (as either glycerophospholipids or sphingophospholipids).
4.Complex lipids- lipoproteins
Key Differences
1. Structure: • Non-Glycerine Lipids: Do not contain glycerol. • Complex Lipids: Contain glycerol and additional components like phosphate groups, carbohydrates, or proteins. 2. Functions: • Non-Glycerine Lipids: Serve various roles including hormone production (steroids), energy storage (fatty acids), and protective barriers (waxes). • Complex Lipids: Primarily structural components of cell membranes (phospholipids), involved in cell recognition and signaling (glycolipids), and lipid transport (lipoproteins). 3. Presence in Biological Systems: • Non-Glycerine Lipids: Found in various tissues and perform a wide range of functions. • Complex Lipids: Predominantly found in cell membranes and involved in cellular interactions and metabolism.
State and define four physical and chemical characteristics each of lipids (this is biochem so we are more interested in the chemical aspect)
Physical
➢Lipids are either liquid or non-crystalline solid at room temp-example of liquid is oil and example of solids are waxes
➢Insoluble in water-example is waxes
➢pure fats and oils are colorless, odorless and tasteless (Pure fats (pure triglycerides) are usually colorless, odorless, and tasteless. But when they are broken down (especially during cooking, digestion, or spoilage), they release fatty acids and other small molecules — these smaller molecules are what produce flavors, smells, and even some colors.
In short: Triglycerides themselves don’t have strong sensory qualities, but their breakdown products do.)
➢No ionic charges- only is sphingophospholipids have ionic charges . Most lipids are neutral and do not carry ionic charges. However, sphingophospholipids, such as sphingomyelins, can have ionic charges due to their phosphate groups.
➢Pure fats and oils are energy rich molecules. Pure fats and oils are energy-dense molecules, providing a high amount of energy when metabolized.
➢Soluble in organic solvents like chloroform, ether and acetone. Organic Solvents:
- Contain carbon.
- Dissolve organic compounds.
- Examples: hydrocarbons(such as Benzene, toluene,xylene),alcohols(ethanol,isopropanol),ethers such as(diethyl ether and tetrahydrofuran),esters(such as ethyl acetate and butyl acetate) ,ketones(such as acetone and methyl ethyl ketone)
Inorganic Solvents:
- Do not contain carbon.
- Dissolve inorganic compounds.
- Examples: Water, acids(hydrochloric acid),bases(sodium hydroxide),salts(ammonium chloride in solution)
•Chemical
➢hydrolysis:- hydrolysis of lipid such as triacylglycerol is done through lipases enzyme during the digestion of fat which results in fatty acids and glycerol. Hydrolysis is basically using water to break something down. So the lipase enzyme adds a hydroxyl group and hydrogen atom to the triacylglycerol to break it down or apart into glycerol and three fatty acids
Types are acid catalyzed hydrolysis and base catalyzed hydrolysis. Saponification is a base catalyzed hydrolysis
In saponification, hydrogen ions (H⁺) are not involved. The reaction specifically relies on hydroxide ions (OH⁻) provided by the strong base.
Here’s a quick comparison:
• Saponification: Uses a strong base (like sodium hydroxide, NaOH) to provide hydroxide ions. These ions hydrolyze triglycerides into glycerol and fatty acid salts. There is no direct role for hydrogen ions in this process. • Acid-Catalyzed Hydrolysis: In contrast, acid-catalyzed hydrolysis (also known as acid hydrolysis) uses hydrogen ions (H⁺) from an acid to hydrolyze ester bonds in triglycerides, producing glycerol and free fatty acids.
➢Saponification:- hydrolysis of fat by an alkali (any base such as sodium hydroxide or potassium hydroxide) is known as saponification. the products formed are glycerol and alkali salts of fatty acids (plus the metal. So if sodium hydroxide,sodium metal is also released) which are known as soaps. The metal salts are also known as the salts of the fatty acids released during the reaction. For instance, if sodium hydroxide is used, you get sodium stearate or sodium palmitate (depending on the fatty acids involved), which are common types of soap.
Summary: The “metal salts” in saponification are indeed the soap, resulting from the reaction between fatty acids and the metal hydroxide base.
Hydrolysis generally involves breaking bonds in a molecule using water. It typically involves the addition of a hydrogen ion (H⁺) and a hydroxyl ion (OH⁻) from water to split the molecule.
Saponification is a specific form of hydrolysis where a fat or oil (triglyceride) reacts with a strong base (like sodium hydroxide or potassium hydroxide) rather than with water alone. Here’s how it works:
• In saponification, the base (OH⁻) reacts with the ester bonds in triglycerides. This reaction breaks the ester bonds, resulting in the formation of glycerol and fatty acid salts (soap).
Yes, in saponification, the base facilitates the hydrolysis of triglycerides. Here’s how it works:
1. Base-Catalyzed Hydrolysis: The base (such as sodium hydroxide or potassium hydroxide) provides hydroxide ions (OH⁻). These hydroxide ions attack the ester bonds in triglycerides, breaking them apart. 2. Reaction: The triglyceride (a type of fat or oil) reacts with the hydroxide ions in a base-catalyzed reaction, leading to the formation of glycerol and fatty acid salts (soap)
➢Hydrogenation:- hydrogenation of unsaturated fat in the presence of a catalyst is known as hardening. It is mainly used for converting the liquid fats and unsaturated fats(have double bonds). So you add hydrogen to remove the double bonds. Double bonds aren’t so good because they disrupt structures and you can’t stack more structures on top of the other if they have double bonds.double bonds (unsaturated fatty acids) are not stable too. Liquid fats, also known as unsaturated fats, have double bonds in their fatty acid chains because these bonds prevent the molecules from packing tightly together. Here’s how it works:
1. Double Bonds in Unsaturated Fats: • The presence of one or more double bonds between carbon atoms in the fatty acid chains causes a kink or bend in the structure. This makes it difficult for the fatty acids to stack closely or align neatly, which reduces the strength of the interactions between the molecules. • Unsaturated fats (liquid) have one or more double bonds in their fatty acid chains. • Hydrogenation adds hydrogen atoms to these double bonds. • Saturated fats (solid) have no double bonds in their fatty acid chains, making them more stable and solid at room temperature. Hydrogenation also increases the shelf life and stability of the fats. Catalysts used include Nickel,platinum and palladium. Also, clinically, hydrogenated fats(Produce trans fats which are also bad) are bad because they raise LDL. Which can cause heart problems. So hydrogenated fats are seen in margarine and baked goods. For hydrolysis, if a person has a problem with production of lipase from the pancreas, there won’t be any hydrolysis of fats. This will make the fat go into the stool (steatorrhea) cuz the body can’t absorb the triglycerides. It can only absorb it as fatty acids and glycerol ➢Peroxidation:- peroxidation of lipids exposed to oxygen is responsible not only for breaking of foods but is also used for damage to tissues where it may cause cancer.its dangerous if it occurs in biological systems because it’s a form of oxidative stress where ROS like hydroxyl and superoxide radicals will bind to lipids and make them unstable or radicals too. This sets of a chain reactions causing everything in the cell to be unstable . Process: peroxidation is Oxidative damage of lipids due to exposure to oxygen, forming reactive oxygen species (ROS) like hydroxyl and superoxide radicals. This leads to cell instability and potential tissue damage. • Clinical Impact: Increases the risk of cancer and accelerates aging processes. Clinically relevant in: • Oxidative Stress: Associated with various diseases including cancer and neurodegenerative disorders. A patient with atherosclerosis is found to have elevated levels of lipid peroxides in their blood, indicating oxidative stress. A patient with early signs of neurodegenerative disease, such as Alzheimer’s disease, exhibits increased oxidative damage to lipids in brain tissue. A patient with acute inflammatory conditions, such as rheumatoid arthritis, may have increased levels of lipid peroxidation products in their serum. • Antioxidant Therapy: May help mitigate oxidative damage. ➢Rancidity:- When any oil or fat produces unpleasant odour, they are termed as rancidity. Rancidity is caused after oxidation and hydrolysis. Oxidative rancidity occurs in triacylglycerol containing unsaturated fatty acids.rancid oils don’t have essential fatty acids in them cuz those essential acids have been broken down So someone who takes in rancid oils usually have nutritional deficiencies and they also have GIt discomfort
Change at the R group of the structure of fatty acids increases by a factor Of twos. Ranges from 2-24 carbons. True or false
What are the classifications of fatty acids
Omega fatty acids are always unsaturated
Oils have what type of fatty acids?
Fats have what type of fatty acids?
Where does the methyl group point and where is it located in isobranched chain fatty acids ?
What about in anteisobranched chain fatty acids
Saturated-straight chain
Unsaturated(due to presence of double bonds)- cis and trans unsaturated. Oils have more cis unsaturated fatty acids while fats have more saturated fatty acids or trans unsaturated fatty acids cuz it’s more easy to pack them on top of each other. The cis one has a bent shape so it’ll be difficult to do so. Trans Unsaturated Fatty Acids: Formed during hydrogenation.
Branched chain fatty acids: isobranched and anteiso-branched chain. The isobranched is closer to the end of the fatty acid chain and the methyl branch points down while the anteisobranched is a bit away from the end of the fatty acid chain as compared to the iso and it’s methyl group points up. Isobranched: Methyl branch close to the end, pointing down.
• Anteiso-branched: Methyl branch farther from the end, pointing up.
Isobranched vs. Anteiso Branched: Both have branching, but the location of the branch (methyl group) differs. “Iso-” refers to the branch on the penultimate carbon, while “anteiso-” refers to the branch on the third-to-last carbon.
Complex fatty acids(possess other functional groups)- Beta hydroxyl(generating hydroxyl group on beta carbon to get energy from fatty acids), gamma cyclohexyl, cyclopropene
Great question! Here’s the simple reason:
Saturated fatty acids have no double bonds —
• All the carbon atoms are “saturated” with hydrogen.
• This makes their chains straight (no kinks or bends).
Because the chains are straight, they can:
• Pack very closely together
• Form stronger forces (van der Waals forces) between them.
• This tight packing makes them solid at room temperature (like butter or lard).
Simple summary:
No double bonds = straight chains = tight packing = solid.
In contrast:
• Unsaturated fats have double bonds that cause kinks.
• Kinked chains cannot pack tightly → so they are liquid at room temperature (like vegetable oil).
Quick way to remember:
Straight chains stick → Solid. Bent chains can’t stick → Liquid.
Would you also like me to quickly show how one little double bond changes everything visually? (It’s super easy to see why solid vs liquid happens!)
What is the difference between cis and trans fatty acids
Note: cis fatty acids are present in cell membranes so that they won’t be packed on top of each other and will be more flexible.
Cis and trans fatty acids are types of unsaturated fatty acids, distinguished by the configuration of hydrogen atoms around their double bonds.
-
Structure: In cis fatty acids, hydrogen atoms are on the same side of the double bond. This causes a bend or kink in the fatty acid chain. Cis: Think of “Cis = Same”. In cis isomers, the substituent groups on either side of the double bond are on the same side. You can visualize it as if they are “sitting together”. Cis: Picture two friends “Sitting Side by Side”. The letter “S” in “Cis” can help you remember that the groups are on the same side of the double bond.
example of cis; • Cis-2-butene: Both methyl groups are on the same side of the double bond. - Natural Occurrence: Most naturally occurring unsaturated fats in plant oils and fish are in the cis configuration.
- Health Impact: Generally considered healthier, cis fatty acids can help reduce bad cholesterol (LDL) and increase good cholesterol (HDL).
- Structure: In trans fatty acids, hydrogen atoms are on opposite sides of the double bond. This results in a straighter chain, similar to saturated fats. • Trans: Think of “Trans = Transverse” (meaning across). In trans isomers, the substituent groups are on opposite sides of the double bond. You can visualize it as if they are “across from each other”. Trans: Picture a “Transverse Line” crossing the double bond, where the groups are across from each other. The “T” in “Trans” can remind you that the groups are on opposite sides.
Example of trans:
• Trans-2-butene: Methyl groups are on opposite sides of the double bond.
- Formation: Trans fats can be found in small amounts naturally in some animal products, but are primarily formed during industrial hydrogenation of vegetable oils (e.g., in margarine, snack foods, and fried foods).
- Health Impact: Trans fats are associated with increased risk of heart disease, as they raise bad cholesterol (LDL) and lower good cholesterol (HDL). They can also increase inflammation and contribute to insulin resistance.
Regulations have been implemented in many countries to reduce or eliminate the use of trans fats in food products due to their adverse health effects.
Whag fatty acids are the most common in the body?
How many. At one does stearic acid have?
How many carbons does palimitic acid have?
Difference between oleic acid, stearic acid and linoleic acid
How many carbons does butyric acid have?
Another name for butyric acid is ?
How many carbons does ethanoic acid have?
State their sources in nature
Acetic acid
Butyric acid
Caproic acid
Caprylic acid
Capric acid
Lauric acid
Myristic acid
Palmitic acid
Stearic acid
Arachidic acid
Behenic acid
Palimitic acid - 16 carbons. Systemic name: hexadecanoic acid
Stearic acid -18 carbons (oleic acid has 18 carbons and is unsaturated but Stearic acid is saturated, Structure of linoleic acid is 18 carbons with two double bonds (polyunsaturated))
Systemic name: octadecanoic acid
Acetic-2 carbons Systemic name:ethanoic acid
Butyric acid -4 carbons systemic name:butanoic acid
oSaturated fatty acids may be envisaged as based on acetic acid (CH3 —COOH) as the first member of the series in which —CH2 — is progressively added between the terminal CH3 — and —COOH groups
oFatty acids in biological systems usually contain an even number of carbon atoms, typically between 14 and 24. The 16- and 18-carbon fatty acids are most common
oThe hydrocarbon chain is almost invariably unbranched in animal fatty acids.
Acetic acid: vinegar
Butyric: breast milk
Caproic Acid (C6:0)
• Found in dairy (goat’s milk, cow’s milk) and coconut oil.
• Antimicrobial properties.
2. Caprylic Acid (C8:0)
• Found in coconut oil, palm kernel oil, goat’s milk.
• Antibacterial, antifungal, and easily absorbed for energy.
3. Capric Acid (C10:0)
• Found in coconut oil, palm kernel oil, goat’s milk.
• Antibacterial properties, used in medicinal products.
4. Lauric Acid (C12:0)
• Found in coconut oil, palm kernel oil, breast milk.
• Antimicrobial, converted into monolaurin with antiviral properties.
5. Myristic Acid (C14:0)
• Found in coconut oil, palm kernel oil, dairy.
• Involved in lipid synthesis and found in high levels in cell membranes.
6. Palmitic Acid (C16:0)
• Common in animals and plants (palm oil, meat, dairy).
• Major component of body fats but excessive consumption is linked to cardiovascular problems.
7. Stearic Acid (C18:0)
• Found in animal fats, cocoa butter, shea butter.
• Neutral in terms of cholesterol, used in soaps and cosmetics.
8. Arachidic Acid (C20:0)
• Found in peanuts, corn oil.
• Important for phospholipids in cell membranes.
9. Behenic Acid (C22:0)
• Found in rapeseed oil (canola oil), peanut oil.
• Used in cosmetics for its emollient properties.
Hydrolysis of Branched Fatty Acids:
• Branched-chain fatty acids, such as phytanic acid, require specific enzymes for hydrolysis. Lipases and esterases typically break down fatty acids, but if the enzymes are absent or impaired, it can cause metabolic disorders (e.g., Refsum disease).
State the types of unsaturated fatty acids
Most naturally occurring unsaturated fatty acids are cis
So the bad one is the saturated and trans fatty acids cuz they stick together and can stick on blood vessels to cause atherosclerosis that’s why they say take more cis unsaturated and omega fatty acids
Monounsaturated Monounsaturated (monoethenoid, monoenoic) acids, containing one double bond
•Polyunsaturated (polyethenoid, polyenoic) acids, containing two or more double bonds.
The configuration of the double bonds in most unsaturated fatty acids is cis geometric isomer.
The double bonds in polyunsaturated fatty acids are separated by at least one methylene group.
State the biological importance of fatty acids. 4
Storage form of energy (TGs)
Structural components of biological membranes (phospholipids, sterols, TGs)
? Serves as thermal insulators in the subcutaneous tissues and around certain organs (TGs in adipose tissues)
? Lipophilic bile acids aid in emulsification, digestion and absorption of dietary lipids as well as being a form of bioactive lipids
Serves as biologically active molecules exerting a wide range of function (signalling, membrane trafficking)
Roles of Lipids
> Energy storage (fatty acids, triacylglycerols)
> Structural elements (phospholipids, cholesterol)
> Hormones (sex hormones e.g. Estrogen)
> Enzyme cofactors (coenzyme A)
> Electron carriers (coenzyme Q, plastpquinone)
> Light-absorbing pigments (carotenoids. Example of this are retinols which are important for night vision)
> Hydrophobic anchors ; most proteins aren’t attached to the plasma membrane so they hang and are anchored by dolichols. These anchors are typically lipids that interact with the hydrophobic regions of proteins, helping to stabilize their position within the membrane.(dolichols)
> Emulsifying agents (bile salts)
• Intracellular messengers (phosphatidyl inositol)
Alright — let’s break it down very simply:
Bile salts are emulsifying agents because they help break big fat droplets into tiny droplets in the small intestine.
This makes it easier for enzymes (like lipase) to digest the fats.
Here’s how it works:
• Fats normally don’t mix well with water (they clump together).
• Bile salts have two sides:
• One side loves water (hydrophilic).
• One side loves fat (hydrophobic).
• So bile salts stick to fat droplets with their fat-loving side, and face the water with their water-loving side.
• This breaks the big fat into many small, tiny droplets suspended in water — this is called an emulsion.
In short:
Bile salts break fats into small pieces and keep them spread out, so fat-digesting enzymes can work better.
1)-Fatty acids are the main components of dietary lipids. The human body stores energy such as fats in the form of triglycerides.
2)- Fatty acids are also required for the formation of membrane lipids such as phospholipids and glycolipids.
3) -They are required for the esterification of cholesterol to form cholesteryl esters. Cholesterol rarely occurs in its free form. fatty acids are combined with cholesterol so that the cholesterol can easily be managed and shuffled across the body . Cholesteryl esters are formed through the esterification of cholesterol with fatty acids. This process is important for cholesterol transport and storage in the body. Biological significance includes Cholesteryl Esters in Lipoproteins: Cholesteryl esters are found in lipoproteins like LDL (low-density lipoprotein) and HDL (high-density lipoprotein). They help in the transport and storage of cholesterol in the bloodstream.
Esterification is a chemical reaction in which a carboxylic acid(example is fatty acid ) reacts with an alcohol(example is cholesterol which is a sterol and is an alcohol because of the hydroxyl group in it) to form an ester(example is cholesteryl ester) and water(which is a by product of the reaction).
Another Example of Esterification Reaction
Formation of Ethyl Acetate:
• Reactants: Acetic acid (a carboxylic acid) and ethanol (an alcohol).
• Products: Ethyl acetate (an ester) and water.
Formation of Triacylglycerols (Triglycerides)
Another example:
• Reactants: Glycerol (an alcohol. A three-carbon alcohol with three hydroxyl (-OH) groups. ) and three fatty acids (carboxylic acids).
• Products: Triacylglycerol (a triglyceride) and three molecules of water.
4) They act as fuel molecules and are oxidized to produce energy.
5. Used to cushion vital organs in body
What are triglycerides or triacylglycerides (tri-3carbon atoms,acyl-fatty acids,glycerol. Glycerol by nature has three carbon atoms so it can only bind to three fatty acid chains)
What is the end product of the formation of triglycerides?
What is dehydration synthesis
State two reasons dehydration synthesis is important for triglycerides
What enzyme is responsible for undertaking the triglyceride formation reaction?
Three fatty acid chains are bound to glycerol by dehydration synthesis.
So triglycerides are fats. Fats are esters of fatty acids with glycerol.
Just that they have three fatty acids.
Esterification Process:
• Reaction: Fatty acyl transferase enzymes facilitate the esterification of glycerol with fatty acids to form triglycerides (triacylglycerols).
• Dehydration Synthesis: This process involves the removal of a water molecule each time a fatty acid is added to the glycerol molecule.
1. Formation of Strong Covalent Bonds
• Creation of Esters: In the synthesis of triglycerides, dehydration synthesis forms ester bonds between glycerol and fatty acids. These covalent bonds are essential for the stability and function of the triglyceride molecule. Dehydration synthesis results in the removal of water and the formation of a compact, hydrophobic molecule. This is essential for the storage of fats in adipose tissue and for forming lipid bilayers in cell membranes.
Triglycerides or neutral fat and 3 water molecules are the end products of the combination of glycerol and three fatty acids
This reaction is undertaken by fatty acyl transferase
State five characteristics of triglyceride
Between Mono- and Diacylglycerol, which is an important signaling molecule that regulates calcium release inside cells?
What is the specific gravity or density of triglycerides?
oils are liquid at what temperature ?
Fats are solid at what temperature?
Complications of Fat Malabsorption
1. What is the main clinical manifestation of fat malabsorption?
2. Which type of stool is commonly associated with fat malabsorption?
3. What nutritional deficiencies are commonly seen in fat malabsorption?
4. How does fat malabsorption lead to osteoporosis?
5. What effect does fat malabsorption have on weight?
6. Why do patients with fat malabsorption suffer from fatigue?
7. What can happen to a patient’s immune system due to fat malabsorption?
8. How does malabsorption affect vitamin K and lead to bleeding problems?
9. What is the impact of fat malabsorption on bone health?
Causes of Fat Malabsorption
1. What are the primary causes of fat malabsorption?
2. How does pancreatic insufficiency contribute to fat malabsorption?
3. In what way does liver disease affect fat absorption?
4. How does gallbladder dysfunction lead to fat malabsorption?
5. What is the relationship between celiac disease and fat malabsorption?
6. How does short bowel syndrome impact fat absorption?
7. What type of infection can lead to fat malabsorption?
8. How do certain medications, like orlistat, contribute to fat malabsorption?
9. How do inflammatory bowel diseases (IBD) contribute to fat malabsorption?
Characteristics
ØThe triacylglycerols are esters of the trihydric alcohol(alcohol molecule with three hydroxyl groups in it. example of this alcohol is glycerol), glycerol and fatty acids
ØMono- and Diacylglycerol, wherein one or two fatty acids are esterified or bound with glycerol, are also found in the tissues. Diacylglycerol is an important signaling molecule that regulates calcium release inside cells
ØNaturally occurring fats and oils are mixtures of triglycerides.
ØSpecific gravity or density is less than 1.0, that’s why all fats and oils float in water
ØOils are liquids at 20C, they contain higher proportion of unsaturated fatty acids
ØFats are solid at room temperature and contain saturated long chain fatty acid
ØTriglycerides are the storage form of energy in adipose tissue
Malabsorption Syndrome:
1. Bloating and Fatty Stools (Steatorrhea):
• Bloating occurs because the body is unable to digest and absorb fats properly. Undigested fats remain in the intestine, which can lead to discomfort and a feeling of fullness.
• Fatty stools (known as steatorrhea) are a hallmark of fat malabsorption. The undigested triglycerides (fat molecules) pass through the gastrointestinal tract and are excreted in the stool.
• These stools often appear oily or greasy, and they may float because of the low density of triglycerides and their inability to be absorbed properly. This also makes the stool harder to flush due to the high fat content.
2. Difficulty in Flushing Stools:
• Because triglycerides are hydrophobic (water-repelling), they don’t mix well with water and make the stool less dense. This can cause the stool to float or be harder to flush.
3. Lack of Fat-Soluble Vitamins (A, D, E, K):
• Vitamin A, Vitamin D, Vitamin E, and Vitamin K are fat-soluble vitamins, meaning they require fats for absorption.
• In malabsorption syndrome, because fats are not absorbed properly, these fat-soluble vitamins cannot be effectively absorbed either, leading to deficiencies.
Nutrient Deficiencies:
• Deficiency of fat-soluble vitamins (A, D, E, and K) can lead to various clinical manifestations such as night blindness (Vitamin A deficiency), bone pain or fractures (Vitamin D deficiency), neurological problems (Vitamin E deficiency), and excessive bleeding (Vitamin K deficiency).
Complications of Fat Malabsorption:
• Nutritional Deficiencies: Chronic fat malabsorption can lead to deficiencies in essential fatty acids and fat-soluble vitamins. This affects the immune system, bone health, and overall well-being.
• Osteoporosis: Vitamin D deficiency, due to malabsorption, leads to decreased calcium absorption, contributing to bone thinning and fractures.
• Anemia: Vitamin K deficiency, affecting blood clotting, can result in easy bruising or bleeding, and even hemorrhagic anemia in severe cases.
• Hypoproteinemia: The inability to absorb protein and fat can lead to a drop in protein levels in the blood, resulting in edema (fluid retention) and swelling, especially in the lower limbs and abdomen.
- Causes of Fat Malabsorption (Triglycerides)
Primary Causes:
1. Pancreatic Insufficiency:
• Chronic Pancreatitis: Long-term inflammation of the pancreas leads to a reduction in lipase secretion, which is necessary for the breakdown of triglycerides into free fatty acids and monoglycerides. Without this enzyme, triglycerides cannot be efficiently digested.
• Cystic Fibrosis: This genetic disorder causes thick mucus that blocks the pancreatic ducts, preventing the release of digestive enzymes, including lipase.
2. Liver Disease:
• Cirrhosis or other chronic liver conditions can reduce bile production. Bile acids are essential for emulsifying fats, which enables triglycerides to be broken down and absorbed. Without adequate bile, fat digestion is impaired.
3. Bile Acid Deficiency:
• Gallbladder Dysfunction: If the gallbladder is removed or not functioning properly (e.g., due to cholecystectomy), bile release is compromised, which hampers fat digestion and absorption.
4. Celiac Disease:
• Autoimmune disorder in which the ingestion of gluten leads to inflammation in the small intestine and damage to the villi, which are responsible for nutrient absorption. This reduces the surface area for absorption of fats, leading to malabsorption.
5. Short Bowel Syndrome:
• This occurs when a significant portion of the small intestine is removed (e.g., due to surgical resection), leading to reduced absorption of fats, including triglycerides.
6. Infectious Causes:
• Giardiasis: An infection caused by the Giardia parasite can lead to intestinal damage and impaired absorption of fats, including triglycerides.
Secondary Causes:
• Medications: Some medications, like orlistat, which is used to treat obesity, can inhibit lipase activity and cause fat malabsorption.
• Inflammatory Bowel Disease (IBD): Diseases like Crohn’s disease and ulcerative colitis may cause intestinal inflammation and damage, leading to malabsorption of fats.
Here are the questions followed by the answers:
Complications of Fat Malabsorption
1. What is the main clinical manifestation of fat malabsorption?
• Answer: Steatorrhea (fatty stools), which are often bulky, pale, and float due to undigested fats.
2. Which type of stool is commonly associated with fat malabsorption?
• Answer: Floating, greasy, and foul-smelling stools due to the high fat content that cannot be absorbed.
3. What nutritional deficiencies are commonly seen in fat malabsorption?
• Answer: Deficiencies in fat-soluble vitamins (A, D, E, K) due to poor absorption of fats required for their transport.
4. How does fat malabsorption lead to osteoporosis?
• Answer: Fat malabsorption leads to a deficiency in vitamin D, which is essential for calcium absorption, thus increasing the risk of osteoporosis.
5. What effect does fat malabsorption have on weight?
• Answer: It can lead to weight loss and malnutrition because the body is unable to absorb sufficient calories and nutrients from fats.
6. Why do patients with fat malabsorption suffer from fatigue?
• Answer: Due to insufficient absorption of essential nutrients (like fat-soluble vitamins and energy from fats), leading to overall malnutrition and lack of energy.
7. What can happen to a patient’s immune system due to fat malabsorption?
• Answer: Immune dysfunction may occur, as fat-soluble vitamins like Vitamin A and E play important roles in immune function, and their deficiency weakens the immune response.
8. How does malabsorption affect vitamin K and lead to bleeding problems?
• Answer: Vitamin K is essential for blood clotting. Malabsorption prevents proper absorption of vitamin K, leading to an increased risk of bleeding and easy bruising.
9. What is the impact of fat malabsorption on bone health?
• Answer: Lack of fat absorption leads to deficiencies in vitamin D, which is crucial for calcium absorption, resulting in weakened bones and increased risk of fractures (osteoporosis).
Causes of Fat Malabsorption
1. What are the primary causes of fat malabsorption?
• Answer: Causes include pancreatic insufficiency, liver disease, gallbladder dysfunction, celiac disease, short bowel syndrome, and certain infections.
2. How does pancreatic insufficiency contribute to fat malabsorption?
• Answer: The pancreas produces enzymes (like lipase) necessary for fat digestion. Insufficiency in these enzymes leads to improper digestion and malabsorption of fats.
3. In what way does liver disease affect fat absorption?
• Answer: The liver produces bile, which is essential for the emulsification and digestion of fats. Liver disease can reduce bile production, leading to impaired fat absorption.
4. How does gallbladder dysfunction lead to fat malabsorption?
• Answer: The gallbladder stores bile produced by the liver. Gallbladder dysfunction, such as cholecystitis or removal, can impair bile release, hindering fat digestion and absorption.
5. What is the relationship between celiac disease and fat malabsorption?
• Answer: In celiac disease, inflammation and damage to the small intestine reduce its ability to absorb nutrients, including fats, leading to malabsorption.
6. How does short bowel syndrome impact fat absorption?
• Answer: Short bowel syndrome occurs when a significant portion of the small intestine is removed or damaged, reducing the surface area available for fat absorption.
7. What type of infection can lead to fat malabsorption?
• Answer: Chronic infections, particularly in the gastrointestinal tract (e.g., giardiasis), can damage the intestinal lining and impair fat absorption.
8. How do certain medications, like orlistat, contribute to fat malabsorption?
• Answer: Orlistat is a weight-loss drug that inhibits pancreatic lipase, preventing fat breakdown and absorption in the small intestine.
9. How do inflammatory bowel diseases (IBD) contribute to fat malabsorption?
• Answer: Inflammatory bowel diseases, such as Crohn’s disease and ulcerative colitis, cause inflammation in the intestines, which can lead to damage of the absorptive surfaces and decreased fat absorption.
State five functions of triglycerides
What percentage of the body’s resting energy needs does compact stored fat provide?
Chylomicrons are a specific type of lipoprotein particle that primarily transports dietary lipids from the intestines to other tissues in the body.
Note: No, triglycerides do not contribute directly to cell membrane formation. Instead, phospholipids are the primary lipids involved in forming cell membranes. Phospholipids have a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) tails, which arrange themselves into a bilayer, creating the structural foundation of cell membranes. This bilayer forms a stable barrier between the interior of the cell and its external environment, allowing selective permeability and communication.
Triglycerides, on the other hand, primarily serve as energy storage molecules and are stored in adipose tissue. They do not have the amphipathic properties necessary for forming the bilayer structure of cell membranes.
Functions
üMajor lipid in the body and diet
üStored fat provides about 60% of the body’s resting energy needs – compactly!
üInsulation and protection-especially in babies. They have a lot of brown fat which is easily metabolized for them to keep warm. Animal bear also has huge triglycerides stores so that during the winter season, it breaks it down to keep warm. Brown fat, also called brown adipose tissue, helps maintain your body temperature when you get too cold. It’s the same fat that bears use to stay warm when they hibernate. Babies are born with a lot of brown fat behind their shoulder blades. White fat stores excess energy while brown fat burns it to generate heat, which is why hibernating bears and newborns need it.
üCarrier of fat-soluble compounds:example is fat soluble vitamins,formation of lipoproteins(phospholipids also help in this), Also Within cells, triglycerides can be stored in lipid droplets and provide a source of fatty acids for membrane synthesis and signaling molecules.
üSensory qualities – flavor and texture: Triglycerides enhance food’s sensory qualities by acting as carriers for fat-soluble flavor compounds and enhancing aromas, particularly when cooked. They provide a creamy, smooth mouthfeel in products like butter and cream, and contribute to the moist, tender texture of baked goods. In pastries, solid fats from triglycerides create layers that result in a flaky texture. Overall, triglycerides enrich the flavor and texture, making foods more enjoyable and satisfying.
What is the importance of diacylglycerol
Diacylglycerol is an important signaling molecule that regulates calcium release inside cells
Why are phospholipid called amphipathic molecules
How are phospholipids classified?
Phospholipids have a polar or hydrophilic head which is formed by the phosphate backbone and glycerol group of the fatty acid. It also has hydrophobic tails which interact with themselves. They are amphipathic cuz they can exist in both aqeous solutions and other solutions due to the polar head and hydrophobic tails
Contain in addition to fatty acids and glycerol/or other alcohol, a phosphoric acid residue, nitrogen containing base and other substituents.
Most phospholipids may be regarded as derivatives of phosphatidic acid , in which the phosphate is esterified with the —OH of a suitable alcohol.
They are amphipathic molecules containing a polar head and a hydrophobic portion
Classification:
•Glycerophospholipids- Glycerol is the alcohol group.
Examples-
Phosphatidyl ethanolamine
Phosphatidyl serine
Phosphatidyl inositol
Phosphatidic acid
Cardiolipin
Plasmalogen
Platelet activating factor
Phosphatidyl Glycerol
•Sphingophospholipids- Sphingol is the alcohol group
Example: Sphingomyelin
When phospholipids R is replaced with the following molecules, what are their functions and locations?
1. an H molecule
2.ethanolamine
3.choline
4.serine
5.glycerol
6. myo-Inositol 4,5-bisphosphate
7. phosphatidylglycerine
Barth syndrome and cardiolipin
Plasmalogens and platelet activating factor which are
Both glycerophospholipids are bound by an ether bond and not an ester bond like the others
1.When replaced with an H, it is phosphatidic acid
2.When replaced with ethanolamine,it is phosphatidylethanolamine- (this is distributed across the cell membranes all over the body but is more present in the brain and nervous tissues). It’s also called cephalin.
3.When replaced with choline, it is phosphatidylcholine(or lecithin) -(present in the brain and are the most abundant phospholipids in the cell membrane of humans). These are more in the inner leaflet. Represents a large proportion of the body’s store of choline (needed for neurotransmission in for of acetyl choline).
* Dipalmitoyl lecithin is a very effective surface-active agent and a major constituent of the lung surfactant, It prevents adherence of alveolar walls, due to surface tension, of the inner surfaces of the lungs. Its absence from the lungs of premature infants causes respiratory distress syndrome. Dipalmitoyl lecithin starts around 30 weeks of gestation and acts as a surface active agent and as a major component of lung surfactant.
Dexamethasone is a steroid.
• It helps speed up the baby’s lung maturity when given to the mother before delivery.
• It stimulates the baby’s lung cells (type II pneumocytes) to produce more surfactant —
including more dipalmitoyl lecithin!
Dipalmitoyl lecithin = Dipalmitoyl phosphatidylcholine (DPPC), not just dipalmitoyl choline.
4.When replaced with serine, it is phosphatidylserine-(signal molecule that warns body that this molecule that the cell is found on is in danger and needs to be destroyed to protect the neighboring cell. It is found in the inner leaflet. Phosphatidylserine exposure on the outside of a cell signals the body to remove the cell to protect surrounding tissue. So it flips its leaflet from in to outside.
5.When replaced with glycerol, it is phosphatidylglycerol
6.When replaced with myo-Inositol 4,5-bisphosphate it becomes Phosphatidylinositol
4,5-bisphosphate(this serves as a signaling molecule that regulates calcium balancing).
: Phosphatidylinoston 4,5 Bisposphate is an important constituent of the cell membrane phospholipids; upon,
stimulation by a suitable hormone agonist, it is cleaved into diacylglycerol and inositol trisphosphate, both of which act as internal signals or second messengers. So when they say:
“Inositol in phosphatidylinositol is a stereoisomer (myo-inositol)”
they just mean:
“The specific form of inositol used is the myo-inositol type.”Super simple explanation:
1. The agonist binds its receptor.
2. The receptor activates an enzyme called phospholipase C (PLC).
3. PLC cuts phosphatidylinositol 4,5-bisphosphate (PIP2) into:
• Diacylglycerol (DAG) → stays in the membrane and activates Protein Kinase C (PKC).
• Inositol triphosphate (IP3) → goes into the cytoplasm and causes Ca²⁺ release from the ER.
7.When replaced with phosphatidylglycerin, it becomes cardiolipin-(predominates mitochondria cell membranes in the heart)
Good question — here’s the clear and simple link:
Barth Syndrome and Cardiolipin
• Barth syndrome is a genetic disease caused by mutations in the TAZ gene.
• The TAZ gene makes an enzyme called tafazzin.
What tafazzin normally does:
• Tafazzin remodels cardiolipin (it helps make cardiolipin the right shape and composition).
• Cardiolipin is super important for the inner mitochondrial membrane — it keeps mitochondria working properly (energy production, membrane stability, etc.).
In Barth syndrome:
• Tafazzin is defective.
• Cardiolipin becomes abnormal — either the wrong structure or too little cardiolipin.
• Mitochondria can’t produce energy properly.
• This leads to symptoms like muscle weakness, heart failure, infections (because mitochondria power muscles and immune cells).
Simple one-liner:
Barth syndrome is caused by defective cardiolipin remodeling, leading to mitochondrial dysfunction.
Extra short:
Barth = bad cardiolipin = bad mitochondria.
Would you like a quick table summarizing Barth syndrome features too (genetic cause, main problems, symptoms)?
It’s very easy to memorize!
Want me to send it?
Alright — let’s go through your points clearly and simply:
Plasmalogens:
• Plasmalogens are a special type of phospholipid.
• The difference is that at position 1 of the glycerol backbone,
instead of a normal fatty acid attached by an ester bond,
there is a fatty alcohol attached by an ether bond.
(Ether linkage = oxygen linking two carbons directly, no C=O in between.)
About your points:
1. “Ether linkage” →
Yes! Plasmalogens have an ether bond at the first carbon (C1) of glycerol.
2. “Top sign (ene)” and “0l” — I think you meant:
“Plasmalogens make up about 20% of the phospholipids of brain and muscle.”
Correct!
They are abundant in the brain, heart, and muscle tissues.
3. “Choline, serine, or inositol may be substituted for ethanolamine” →
Yes!
• Normally, plasmalogens have ethanolamine as the head group (phosphatidylethanolamine type).
• But sometimes, choline, serine, or inositol can replace ethanolamine to create different types of plasmalogens.
Quick simple line:
Plasmalogens are ether-linked phospholipids important in brain, heart, and muscle, usually with ethanolamine, but sometimes with choline, serine, or inositol.
Summary:
Feature Detail
Bond at C1 Ether bond
Organs rich in plasmalogens Brain, heart, muscle
Usual head group Ethanolamine
Other possible head groups Choline, serine, inositol
Would you also like me to show you a super simple structure sketch of a plasmalogen so you can “see” it once and always remember?
It’s very easy once you see it!
Want me to draw it?
Platelet activating factor (PAF)
Ether dly can phagali alkyl group in an ether link to carbon 1
• An acetyl residue at carbon 2 of the glycerol backbone.
• Synthesized and released by various cell types
• PAF activates inflammatory cells and mediates hypersensitivity, acute inflammatory and anaphylactic reactions
• Causes platelets to aggregate and degranulate and neutrophils and alveolar macrophages to generate superoxide radicals
So PAF in mast cells
Jjkkk
State ten functions of phospholipids (functions of glycerophospholipids and functions of sphingophospholipids)
Functions of glycero-phospholipids
• Components of cell membrane, mitochondrial membrane and lipoproteins
• Participate in lipid absorption and transportation from intestine
• Play important role in blood coagulation
• Required for enzyme action- especially in mitochondrial electron transport chain
* Membrane phospholipids acts as source of arachidonic acid
* Act as reservoir of second messenger- Phosphatidyl Inositol
* Act as cofactor for the activity of lipoprotein lipase
• Phospholipids of myelin sheath provide insulation around the nerve fibers
• Dipalmitoyl lecithin acts as a surfactant
Specifically, phosphatidylcholine (a glycerophospholipid) is involved.
• Phosphatidylcholine is a component of lipoproteins (like chylomicrons and VLDL).
• It helps organize and present ApoC-II (the real cofactor) properly on the lipoprotein surface.
• Without the phospholipid layer, ApoC-II might not work properly to activate lipoprotein lipase.
Simple way to think about it:
• Glycerophospholipids (like phosphatidylcholine) help arrange the lipoprotein surface.
• This makes it easier for ApoC-II to activate lipoprotein lipase. Good question — let’s keep it simple:
Cofactor for Lipoprotein Lipase (LPL):
• The cofactor is Apolipoprotein C-II (ApoC-II).
How it works:
• Lipoprotein lipase (LPL) needs to be “turned on” to work.
• ApoC-II binds to LPL and activates it.
• Once activated, LPL can break down triglycerides in chylomicrons and VLDL into fatty acids and glycerol.
(Without ApoC-II, LPL would be inactive or very slow.)
Simple line to memorize:
ApoC-II acts as a cofactor that activates lipoprotein lipase to hydrolyze triglycerides.
Extra tiny flow:
Chylomicrons/VLDL → ApoC-II activates LPL → LPL cuts triglycerides → Free fatty acids + glycerol.
Would you also like a quick disease example where ApoC-II is deficient? (It helps you remember why it’s important!)
Want me to tell you?
Others:
Components of cell membrane, mitochondrial membrane and lipoproteins(triglycerides won’t help in this cuz they are not ampiphatic)
●Participate in lipid absorption and transportation from intestine
●Play important role in blood coagulation- allow for clotting factors and enzymes involved in coagulation cascade to embed on blood vessel membrane and be fixed to it. In bleeding, the integrity of the cell membrane in the vessels have been destroyed. Phospholipids are crucial in blood coagulation due to their involvement in several key processes:
- Platelet Activation: Phosphatidylserine flips to the outer leaflet of platelet membranes, promoting clotting factor activation and aggregation.
- Coagulation Cascade: Phosphatidylinositol and its metabolites are involved in cellular signaling and calcium ion release, which are essential for clotting factor activation.
- Formation of Coagulation Complexes: Phospholipid membranes provide a surface for the assembly of enzyme-substrate complexes needed for the coagulation cascade.
- Intrinsic and Extrinsic Pathways: Phospholipids support the assembly of tenase and prothrombinase complexes in the intrinsic pathway and facilitate tissue factor interaction in the extrinsic pathway.
Overall, phospholipids play a vital role in ensuring efficient and regulated blood clot formation.
●Required for enzyme action- especially in mitochondrial electron transport chain
●It plays a major role in the transportation and removal of cholesterol from the cells.
●It forms the structural components of the cell membrane with the association of proteins.
●They act as surfactants (these make the lungs able to expand freely without difficulty and contract freely without collapsing completely. Surfactants in the lungs are produced in the last four weeks of gestation. So if baby is premature, the surfactant won’t be fully developed so their given dexamethasone which will help with production of surfactant) in the respiratory system and are also involved in the coagulation of blood cells.
●It helps in the synthesis of different lipoproteins, prostacyclins(blood vessel dilation), prostaglandins(blood vessel constriction and inflammation ) and thromboxanes
F Certainly! Here’s a detailed explanation of each function of phospholipids:
- Components: Phospholipids are fundamental components of cell membranes. They form a bilayer with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward.
- Function: This bilayer creates a semi-permeable membrane that maintains the integrity of the cell, controls the movement of substances in and out, and supports membrane proteins involved in various cellular functions. In mitochondria and lipoproteins, phospholipids also contribute to membrane structure and function.
- Role in Digestion: Phospholipids are crucial for the digestion and absorption of dietary fats. They form micelles, which are tiny lipid droplets that facilitate the absorption of lipids and fat-soluble vitamins in the intestine.
- Transport: Once absorbed, lipids are incorporated into chylomicrons (a type of lipoprotein) and transported through the lymphatic and circulatory systems to various tissues.
- Platelet Activation: Phosphatidylserine, a type of phospholipid, flips from the inner to the outer leaflet of the platelet membrane upon activation. This exposure promotes the activation of clotting factors and aids in the formation of blood clots.
- Coagulation Cascade: Phosphatidylinositol and its derivatives play a role in signaling pathways that lead to clotting. They help release calcium ions, which are crucial for the activation of clotting factors.
- Complex Formation: Phospholipid membranes provide a surface for the assembly of enzyme-substrate complexes necessary for the coagulation cascade. This includes the intrinsic and extrinsic pathways of coagulation, where phospholipids support the assembly of tenase and prothrombinase complexes and facilitate tissue factor interaction.
- Mitochondrial Function: In mitochondria, phospholipids are essential for the function of the electron transport chain, which is critical for ATP production. They help anchor and stabilize the enzymes involved in oxidative phosphorylation.
- Lipoprotein Formation: Phospholipids are involved in the formation of lipoproteins, which transport cholesterol and other lipids through the bloodstream. This process is crucial for maintaining lipid homeostasis and preventing cholesterol accumulation in cells.
- Membrane Structure: Phospholipids, along with proteins, form the structural backbone of cell membranes. They help maintain membrane fluidity and flexibility, which is essential for various cellular processes including cell signaling and movement.
- Respiratory Function: In the lungs, phospholipids form surfactants, which reduce surface tension in the alveoli, preventing collapse and aiding in lung expansion. This is especially important for premature infants, whose surfactant production may be insufficient, leading to respiratory distress.
- Clinical Relevance: Surfactant therapy with compounds like dexamethasone can help stimulate surfactant production in premature infants to improve lung function.
- Lipoproteins: Phospholipids are integral to lipoproteins, which transport lipids throughout the body and play a role in lipid metabolism.
- Prostacyclins and Prostaglandins: Phospholipids are precursors for the synthesis of prostacyclins (which cause vasodilation) and prostaglandins (which have various roles including vasoconstriction and inflammation).
- Thromboxanes: These are involved in blood clotting and vascular contraction. Phospholipids provide the substrate for their synthesis.
These detailed functions highlight the multifaceted roles of phospholipids in maintaining cellular function, supporting metabolic processes, and contributing to overall health.
What is the structure or cholesterol
Where can cholesterol be gotten from
Cholesterol has two forms, name them
How is cholesteryl ester formed?
In plasma, the two forms of cholesterol are transported in what?
What is serum total cholesterol
Why is ldl bad cholesterol?
Why is hdl good cholesterol?
When you hear “ol “ in a molecule’s name, know there is a hydroxyl group located in the molecule
•Four linked carbon rings with –OH functional group
•From diet or synthesised de novo (hepatocytes) De novo cholesterol synthesis is the process by which cholesterol is synthesized from simpler molecules within the body, particularly in the liver
LDL is bad cholesterol because the lipoprotein contains lots of cholesterol more than protein content. The more cholesterol a lipoprotein has, the more the likelihood that lipoprotein will be distributing the cholesterol as it travels through the blood to the various parts of the body and if it deposits a lot of the cholesterol in the coronary arteries, you’ll get a heart attack or a stroke
•Cholesterol occurs both as free form or in ester form
•In cholesteryl ester, the hydroxyl group on position 3 is esterified with a long-chain fatty acid. When fatty acids bind to hydroxyl group, cholesterol ester is formed and this helps packaging of cholesterol into lipoproteins for the transport.
•In plasma, both forms are transported in lipoproteins
• sum total of free and ester cholesterol in serum is called serum total cholesterol
HDL is good cholesterol because it gathers cholesterol that has been distributed all over the body and sending it to the liver
Which part of the body is the cholesterol particularly distributed in?
Cholesterol is a major constituent of what?
What is the chief role of cholesterol in pathogenic processes ?
➢Cholesterol is widely distributed in all cells of the body but particularly in nervous tissue.
➢It is a major constituent of the plasma membrane and of plasma lipoproteins.
➢Its chief role in pathologic processes is as a factor in the genesis of atherosclerosis of vital arteries, causing cerebrovascular, coronary, and peripheral vascular disease.
What is a major constituent of gallstones?
How does high cholesterol cause gallstones
.
➢Cholesterol is a major constituent of gallstones(liver is where cholesterol is metabolized to produce bile acids.the bile acids are conjugated in the liver to produce bile salts.the bile salts are sent to the gallbladder for storage.
Bile salt is supposed to emulsify fats.
If there is too much cholesterol in the bile salts such that it can’t emulsify the fat, the cholesterol will form salts with potassium and sodium electrolytes and form the stones. The stones may crystallize together as gallstones
Cholesterol is the precursor of what?
What is the starting molecule for the biosynthesis of cholesterol
It is synthesized in many tissues from acetyl-CoA. Cholesterol Synthesis: Acetyl-CoA is the starting material for the biosynthesis of cholesterol.
It is the precursor of all other steroids in the body, including corticosteroids, sex hormones, bile acids, and vitamin D
State five biological importance of cholesterol
Lipid raft formation
Precursor of vitamin D
Plasma lipoprotein constituent
Bile acid synthesis
Insulates nerve fiber-especially sphingomyelin and phosphatidylcholine
Membrane fluidity- cholesterol gives the membrane rigidity
Membrane homeostasis
Steroid hormone precursor (aldosterone,cortisol,progesterone,estrogen and testosterone)
Cholesterol and Membrane Homeostasis: Cholesterol regulates membrane fluidity and stability, contributing to the barrier function and dynamic adaptation of the membrane.
• Cholesterol and Lipid Rafts: Cholesterol is critical for the formation and maintenance of lipid rafts, which are important for organizing cellular signaling and membrane processes.
What are nucleus acids?
What are nucleotides ?
What two forms can a nucleic acids take on?
What are the types of RNA?
What are the two types of 5 carbon sugars?
A nucleotide is made of three things. Name them
Nucleic acids are monomers of nucleotides true or false
most important macromolecules for the continuity of life
•false. Nucleic acids are polymers of nucleotides.
Yes, it would be incorrect to say that nucleic acids are monomers composed of nucleotides. The correct statement is:
“Nucleic acids are polymers composed of nucleotides.”
- Nucleotides: These are the monomers, the individual building blocks that join together to form nucleic acids.
- Nucleic Acids: These are the polymers made up of long chains of nucleotides.
So, the accurate way to describe the relationship is that nucleotides are the monomers, and nucleic acids (like DNA and RNA) are the polymers composed of these nucleotide monomers.
•Nucleotides are building blocks of Nucleic acid. They are carbon ring structures containing nitrogenous base linked to a 5-carbon sugar (a ribose).So nucleotide is made up of phosphate,nitrogenous base and 5 carbon sugar
Nucleic acids are either RNA or DNA. The RNA is divided into ribosomal RNA(produced by nucleolus),Transfer RNA,Messenger RNA(read by ribosomes for protein synthesis),MicroRNA
Deoxyribose meaning one of the carbons lack oxygen or a hydroxyl group
•5-carbon sugar is either a ribose or a deoxy-ribose making the nucleotide either a ribonucleotide or a deoxyribonucleotide
Which macromolecule is most important for the continuity of life
Nucleic acid
If there’s a problem with your Nucleic acid, you can’t procreate cuz you don’t have genetic material to procreate
