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Questions and Answers
Lipids, including triglycerides, are primarily composed of the elements carbon, ______, and oxygen, giving them their hydrophobic nature.
Lipids, including triglycerides, are primarily composed of the elements carbon, ______, and oxygen, giving them their hydrophobic nature.
hydrogen
The fundamental building blocks or monomers of triglycerides consist of one molecule of ______ and three molecules of fatty acids.
The fundamental building blocks or monomers of triglycerides consist of one molecule of ______ and three molecules of fatty acids.
glycerol
In the formation of a triglyceride from glycerol and fatty acids, a ______ reaction occurs, resulting in the formation of ester bonds and the release of water.
In the formation of a triglyceride from glycerol and fatty acids, a ______ reaction occurs, resulting in the formation of ester bonds and the release of water.
condensation
Saturated fatty acids, characterized by the absence of C=C double bonds in their hydrocarbon chains, typically exhibit higher ______ points compared to unsaturated fatty acids.
Saturated fatty acids, characterized by the absence of C=C double bonds in their hydrocarbon chains, typically exhibit higher ______ points compared to unsaturated fatty acids.
Due to their ______ nature, triglycerides are insoluble in water, which makes them ideal for efficient energy storage without disrupting cellular osmotic balance.
Due to their ______ nature, triglycerides are insoluble in water, which makes them ideal for efficient energy storage without disrupting cellular osmotic balance.
In mammals, triglycerides are primarily stored in specialized cells known as ______, located in adipose tissue, serving as a crucial energy reserve.
In mammals, triglycerides are primarily stored in specialized cells known as ______, located in adipose tissue, serving as a crucial energy reserve.
The efficiency of triglycerides as an energy source is attributed to their high hydrogen content, which allows for greater energy release upon ______ during metabolic processes.
The efficiency of triglycerides as an energy source is attributed to their high hydrogen content, which allows for greater energy release upon ______ during metabolic processes.
Besides energy storage, triglycerides also provide ______, protecting vital organs and providing insulation against extreme temperatures.
Besides energy storage, triglycerides also provide ______, protecting vital organs and providing insulation against extreme temperatures.
Unlike carbohydrates, triglycerides do not significantly affect the ______ potential of cells, mitigating the risk of cellular damage due to osmotic stress.
Unlike carbohydrates, triglycerides do not significantly affect the ______ potential of cells, mitigating the risk of cellular damage due to osmotic stress.
The presence of C=C double bonds in unsaturated fatty acids results in a ‘kink’ in the hydrocarbon chain, reducing ______ forces between molecules and lowering the melting point.
The presence of C=C double bonds in unsaturated fatty acids results in a ‘kink’ in the hydrocarbon chain, reducing ______ forces between molecules and lowering the melting point.
Phospholipids are amphipathic molecules, possessing a ______ head that is hydrophilic and two fatty acid tails that are hydrophobic.
Phospholipids are amphipathic molecules, possessing a ______ head that is hydrophilic and two fatty acid tails that are hydrophobic.
The primary role of phospholipids is to form the ______ bilayer, the structural foundation of cellular membranes in all organisms.
The primary role of phospholipids is to form the ______ bilayer, the structural foundation of cellular membranes in all organisms.
In a phospholipid bilayer, the ______ tails orient themselves inward, away from water, driven by the hydrophobic effect, while the phosphate heads face outward.
In a phospholipid bilayer, the ______ tails orient themselves inward, away from water, driven by the hydrophobic effect, while the phosphate heads face outward.
The arrangement of phospholipids in a bilayer creates a selectively ______ barrier, regulating the passage of molecules into and out of the cell.
The arrangement of phospholipids in a bilayer creates a selectively ______ barrier, regulating the passage of molecules into and out of the cell.
In addition to phospholipids, the fluid mosaic model of membrane structure also includes ______ embedded within the lipid bilayer, which perform a variety of functions.
In addition to phospholipids, the fluid mosaic model of membrane structure also includes ______ embedded within the lipid bilayer, which perform a variety of functions.
The ______ of the cell membrane is influenced by the presence of cholesterol, which acts as a buffer, maintaining fluidity at different temperatures.
The ______ of the cell membrane is influenced by the presence of cholesterol, which acts as a buffer, maintaining fluidity at different temperatures.
The fluid mosaic model describes the cell membrane as a dynamic structure where phospholipids and proteins are free to move ______ within the bilayer.
The fluid mosaic model describes the cell membrane as a dynamic structure where phospholipids and proteins are free to move ______ within the bilayer.
Transmembrane proteins span the entire phospholipid bilayer, often forming ______ that facilitate the transport of specific ions or molecules across the membrane.
Transmembrane proteins span the entire phospholipid bilayer, often forming ______ that facilitate the transport of specific ions or molecules across the membrane.
The asymmetry of the phospholipid bilayer refers to the non-uniform distribution of different types of phospholipids between the two ______ of the membrane.
The asymmetry of the phospholipid bilayer refers to the non-uniform distribution of different types of phospholipids between the two ______ of the membrane.
The arrangement of phospholipids in a ______, with the polar heads facing outward and the nonpolar tails forming the core, creates a structure ideal for drug delivery systems.
The arrangement of phospholipids in a ______, with the polar heads facing outward and the nonpolar tails forming the core, creates a structure ideal for drug delivery systems.
The presence of both integral and peripheral ______ embedded within the cell membrane contributes to the 'mosaic' aspect of the fluid mosaic model.
The presence of both integral and peripheral ______ embedded within the cell membrane contributes to the 'mosaic' aspect of the fluid mosaic model.
Cholesterol functions to ______ the outer surface of the membrane, thus playing a crucial role in reducing the membrane's fluidity.
Cholesterol functions to ______ the outer surface of the membrane, thus playing a crucial role in reducing the membrane's fluidity.
The degree of membrane ______ is affected by the number of double bonds in the fatty acid chains, with increased unsaturation generally leading to greater fluidity.
The degree of membrane ______ is affected by the number of double bonds in the fatty acid chains, with increased unsaturation generally leading to greater fluidity.
The ______ heads of phospholipids point towards the aqueous environment both inside and outside the cell, while the non-polar tails align towards the core of the bilayer.
The ______ heads of phospholipids point towards the aqueous environment both inside and outside the cell, while the non-polar tails align towards the core of the bilayer.
Membrane proteins, including both ______ and peripheral types, play critical roles in cell signaling, transport, and structural integrity.
Membrane proteins, including both ______ and peripheral types, play critical roles in cell signaling, transport, and structural integrity.
Cell ______ proteins in membranes serve as ID tags, essential for distinguishing cells in processes such as the immune response.
Cell ______ proteins in membranes serve as ID tags, essential for distinguishing cells in processes such as the immune response.
[Blank] proteins, functioning as gated channels, bind to specific molecules and pull them into the cell, facilitating transport.
[Blank] proteins, functioning as gated channels, bind to specific molecules and pull them into the cell, facilitating transport.
The hydrophilic phosphate heads and hydrophobic fatty acid tails of phospholipids contribute to their ______ nature, which allows them to form bilayers in aqueous environments.
The hydrophilic phosphate heads and hydrophobic fatty acid tails of phospholipids contribute to their ______ nature, which allows them to form bilayers in aqueous environments.
In phospholipid bilayers, tails interact with each other through ______ interactions, which are crucial to van der Waals forces.
In phospholipid bilayers, tails interact with each other through ______ interactions, which are crucial to van der Waals forces.
In the fluid mosaic model, ______ proteins are seen scattered 'in a random pattern as seen on a mosaic tile', contributing to the model's name.
In the fluid mosaic model, ______ proteins are seen scattered 'in a random pattern as seen on a mosaic tile', contributing to the model's name.
Flashcards
What are triglycerides?
What are triglycerides?
A lipid that is a source of nutrition and an excellent energy store.
What are phospholipids?
What are phospholipids?
A lipid that is a major component of cell membranes.
What are lipids?
What are lipids?
Hydrophobic compounds made of carbon, hydrogen, and oxygen; including fats and oils
What are glycerol and 3 fatty acids?
What are glycerol and 3 fatty acids?
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What is a triglyceride?
What is a triglyceride?
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What are saturated fatty acids?
What are saturated fatty acids?
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What are unsaturated fatty acids?
What are unsaturated fatty acids?
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What is condensation?
What is condensation?
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What are the roles of triglycerides?
What are the roles of triglycerides?
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How do triglycerides structurally fulfill their energy storage role?
How do triglycerides structurally fulfill their energy storage role?
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How do triglycerides structurally fulfill their insulation role?
How do triglycerides structurally fulfill their insulation role?
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What is a phospholipid?
What is a phospholipid?
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What is the role of phospholipids?
What is the role of phospholipids?
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How do phospholipids structurally fulfill their role?
How do phospholipids structurally fulfill their role?
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What is the fluid mosaic lipid bilayer model?
What is the fluid mosaic lipid bilayer model?
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What are channel proteins?
What are channel proteins?
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What are carrier proteins?
What are carrier proteins?
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What are receptor proteins?
What are receptor proteins?
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What are cell recognition proteins?
What are cell recognition proteins?
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What is cholesterol?
What is cholesterol?
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Study Notes
- Two lipids focused on are triglycerides and phospholipids
- Triglycerides are sources of nutrition and energy stores
- Phospholipids form cell membrane
Triglycerides
- Lipids are hydrophobic compounds containing carbon, hydrogen, and oxygen
- Triglycerides are commonly called fats or oils
- Fats are solid at room temperature, oils are liquid
- Triglycerides consist of glycerol and fatty acids
- Glycerol molecule contains 3 carbons with 3 hydroxyl groups
- Fatty acids are long molecules, contain a polar, hydrophilic end and a non-polar hydrophobic "tail"
- Hydrocarbon chains in fatty acids range from 14 to 22 CH2 units in length
- The hydrocarbon chain can be called an "R" group, the formula of a fatty acid is R-COOH
Saturated vs. Unsaturated Fatty Acids
- Saturated fatty acids lack carbon-carbon double bonds in their hydrocarbon chain, have a high melting point and form straight chains
- Unsaturated fatty acids contain carbon-carbon double bonds, possess low melting points and form bent chains
- Polyunsaturated fatty acids (PUFAs) have more than one double bond
- The more hydrogen in a respiratory substrate, the greater the energy released upon oxidation
Lipid Properties
- Lipids are insoluble in water but soluble in organic solvents
- Lipids consist of fatty acids and glycerol
- Fats from dietary sources provide energy, carry fat-soluble vitamins (A, D, E, K) and are a source of antioxidants
- Dietary fats are structural components
Formation of Triglycerides
- The OH group comes from the glycerol
- The H comes from the carboxylic acid group of the fatty acid
- Ester bonds form when triglycerides form through condensation reactions,
Triglyceride Roles
- Glycerol joins with three fatty acid molecules to form a triglyceride molecule through condensation polymerization
- Triglycerides store is for storage, insulation, and protection in adipose or subcutaneous tissue and surrounding organs
- Triglycerides produce more energy per unit mass than other compounds, making them good for energy storage
- Carbohydrates can be mobilized faster for energy as glycogen is stored in the muscles and liver for immediate energy needs
- Triglycerides found in warm-blooded animals typically contain saturated fatty acids, possess a high melting point, and stay solid at room temperature (butter, lard)
- Triglycerides in cold-blooded animals and plants typically contain unsaturated fatty acids, possess low melting points, and stay liquid at room temperature (fish oil, vegetable oil)
- Triglycerides provide insulation for animals in cold regions
- Triglycerides facilitate shock absorption under the skin and around major organs
Structural Fulfillment
- Triglycerides are non-polar as the OH on the glycerol is lost during the ester bond formation, and there are no OH groups to react with water,
- The nonpolar traits will not impact the osmotic potential within cells where it is stored
- The high concentration of hydrogen atoms generates more energy per unit mass compared to carbohydrates like glycogen and starch
- Nonpolar quality, due to the absence of available OH groups, impedes electron flow, thus fat acts as a good insulator
Phospholipids
- Polar, hydrophilic end and a non-polar hydrophobic "tail"
- The phospholipid molecule is composed of glycerol, a phosphate head, and fatty acid tails
- Phosphate head contains a phosphorus atom bonded to oxygen atoms giving it an electrical charge which attracts it to water
- The tails are chains of oily carbon atoms that repel water
- Phospholipids form cell membranes
- Polar heads and nonpolar tails arrange into a bilayer for membranes
Fluid Mosaic Model
- Cell membranes are phospholipid bilayers
- Polar head and non polar tail allows them to arrange themselves in a bilayer of phospholipids forming a membrane
- Heads are attracted to water, tails move away from water.
- Heads point toward the aqueous/watery environment both inside and outside the cell
- Tails arrange towards the core for being hydrophobic and point towards each other away from the aqueous environment
- Tails interact forming hydrophobic interactions known as Van der Waals forces
Fluidity
- Phospholipids move like a sea in constant motion within its layer
- The presence of cholesterol affects the fluidity of the membrane
- Cholesterol stabilizes the cell membrane and increases its melting point at high temperatures as well as inserts into phospholipids and prevent them from interfering with each other to avoid crystallization at low temperatures
- Number of double bonds in the fatty acid chains affect fluidity: the more double bonds, the more fluid the membrane, as fatty acid chains kink with the double bonds and less Van de Waals interactions between tails in the hydrophobic core.
Mosaic
- Membrane proteins, (both integral/transmembrane and peripheral proteins), scatter in the sea of phospholipids in a random pattern
Protein Functions
- Channel proteins form pathways for molecules to diffuse.
- Carrier proteins have a binding site on the protein surface to grab molecules and pull them into the cell through gated channels
- Receptor proteins are molecular triggers that set off cell responses like hormone release or opening of channel proteins
- Cell recognition proteins are ID tags that identify cells to the body's immune system.
- Enzymatic proteins carry out metabolic reactions
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