Lipids quiz #3 Flashcards
Lipids quiz #3
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How do lipids differ from other classes of biomolecules like carbohydrates, proteins, and nucleic acids?
Unlike carbohydrates, proteins, and nucleic acids, lipids do not have consistent monomers and do not form long chains of polymers. What is the primary function of fats and oils in living organisms?
Fats and oils serve as long-term energy storage in animals and plants. What is the difference between saturated and unsaturated fatty acids?
Saturated fatty acids have only single carbon-carbon bonds and are fully saturated with hydrogens, making them solid at room temperature. Unsaturated fatty acids have one or more carbon-carbon double bonds, causing kinks in the chain and making them liquid at room temperature. Why are unsaturated fatty acids liquid at room temperature?
Unsaturated fatty acids are liquid at room temperature because the kinks caused by double bonds prevent tight packing of the molecules. How are triglycerides formed?
Triglycerides are formed by linking three fatty acids to a single glycerol molecule via dehydration synthesis reactions. What is the main function of triglycerides in animals?
Triglycerides serve as the main form of fat storage in animal cells. What is a phospholipid and what are its main components?
A phospholipid is a lipid containing a phosphate group, two fatty acid tails, and a glycerol backbone. Which part of a phospholipid is hydrophilic and which part is hydrophobic?
The head of a phospholipid, which contains the phosphate group, is hydrophilic, while the fatty acid tails are hydrophobic. What is the structural difference between phospholipids and triglycerides?
Phospholipids have two fatty acid tails and a phosphate group attached to glycerol, while triglycerides have three fatty acid tails and no phosphate group. What is cholesterol and why is it important?
Cholesterol is a steroid that is an essential component of animal cell membranes, contributing to membrane structure and fluidity. What are some examples of steroid hormones?
Examples of steroid hormones include testosterone and estrogen. Where can waxes be commonly found in nature?
Waxes are found in places like the cuticle of plant leaves and in beeswax. What is the role of cholesterol in animal cell membranes?
Cholesterol helps maintain membrane structure and fluidity in animal cell membranes. What is hydrolysis and how does it affect lipids?
Hydrolysis is a reaction that uses water to break bonds, splitting triglycerides into glycerol and fatty acids. What is the significance of the amphipathic nature of phospholipids in cell membranes?
The amphipathic nature allows phospholipids to form bilayers, with hydrophilic heads facing water and hydrophobic tails facing inward, creating a selective barrier for cells. What is the health impact of consuming trans fats?
Trans fats are associated with negative health effects, such as increased risk of heart disease, and are generally considered unhealthy. How do waxes help plants survive in dry environments?
Waxes form a protective layer on plant surfaces, reducing water loss and helping plants retain moisture. Why are steroids classified as lipids even though they do not contain fatty acids?
Steroids are classified as lipids because they are hydrophobic and insoluble in water, sharing this key property with other lipids. What is the function of the carboxylic acid group in fatty acids?
The carboxylic acid group allows fatty acids to react with glycerol to form ester bonds in triglycerides and phospholipids. How does the presence of double bonds in fatty acids influence their shape and properties?
Double bonds introduce kinks in fatty acid chains, preventing tight packing and resulting in lower melting points and liquid state at room temperature. What is the general structure of a wax molecule?
A wax molecule consists of a fatty acid linked to a long-chain alcohol. How do lipids contribute to the structure and function of cell membranes?
Lipids, mainly phospholipids and cholesterol, form the structural matrix of cell membranes, providing fluidity, flexibility, and selective permeability.
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