Lipids quiz #1 Flashcards
Lipids quiz #1
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What is the defining characteristic shared by all lipids?
All lipids are hydrophobic, meaning they do not mix well with water. Name four major types of lipids found in living organisms.
Phospholipids, fats, oils, waxes, and steroids. What is the primary function of fats in animals?
Fats serve as long-term energy storage in animals. What is the main function of oils in plants?
Oils provide long-term energy storage in plants. Which type of lipid is a major component of cell membranes?
Phospholipids are the major component of cell membranes. What structural feature makes phospholipids amphipathic?
Phospholipids have a hydrophilic (polar) head and hydrophobic (nonpolar) tails. What is the function of waxes in living organisms?
Waxes provide protection and prevent water loss. Which lipids function as sex hormones and include cholesterol?
Steroids function as sex hormones and include cholesterol. What is the fluid mosaic model?
The fluid mosaic model describes the cell membrane as a fluid structure with embedded proteins that move within the lipid bilayer. Why can small nonpolar molecules cross the cell membrane easily?
Small nonpolar molecules can cross the membrane easily because they can pass through the hydrophobic core of the phospholipid bilayer without energy input. What are the two main parts of a phospholipid molecule?
A phospholipid has a hydrophilic head (containing a phosphate group and glycerol) and two hydrophobic hydrocarbon tails. How do phospholipids arrange themselves in an aqueous environment?
Phospholipids form a bilayer with hydrophilic heads facing outward toward water and hydrophobic tails facing inward away from water. What is the role of cholesterol in the cell membrane?
Cholesterol helps to regulate membrane fluidity and stability. What is the difference between fats and oils in terms of their state at room temperature?
Fats are typically solid at room temperature, while oils are liquid. What is the main function of the cell membrane?
The cell membrane separates the inside of the cell from the outside and controls the movement of substances in and out of the cell. What does it mean for a molecule to be hydrophobic?
A hydrophobic molecule is water-fearing and does not mix well with water. What does it mean for a molecule to be hydrophilic?
A hydrophilic molecule is water-loving and interacts well with water. What is the hydrophobic effect in relation to phospholipids?
The hydrophobic effect drives phospholipids to form membranes in aqueous solutions, with hydrophobic tails clustering away from water. What are the hydrocarbon tails of phospholipids composed of?
The hydrocarbon tails are long chains of hydrogen and carbon atoms. What is the function of embedded proteins in the cell membrane?
Embedded proteins assist in transport, signaling, and structural support within the membrane. What is selective permeability in the context of cell membranes?
Selective permeability means the membrane allows some substances to cross more easily than others. What are glycoproteins and glycolipids, and what is their function in the membrane?
Glycoproteins and glycolipids are membrane molecules with attached carbohydrates that play roles in cell recognition and signaling. How do proteins move within the cell membrane?
Proteins can move laterally within the fluid phospholipid bilayer. What is the main difference between the energy storage roles of carbohydrates and lipids?
Carbohydrates provide short-term energy, while lipids provide long-term energy storage. What is the role of channel proteins in the cell membrane?
Channel proteins facilitate the movement of specific substances across the membrane. Why are phospholipids important for compartmentalization in cells?
Phospholipids form membranes that create distinct internal environments within cells. What is the function of beeswax and earwax in organisms?
Beeswax and earwax protect and prevent water loss. What is the structural difference between steroids and other lipids?
Steroids have a characteristic four-ring structure, unlike other lipids. What is the significance of the fluidity of the cell membrane?
Membrane fluidity allows for movement of proteins and lipids, enabling membrane function and flexibility. What is the main component of the plasma membrane?
The main component of the plasma membrane is the phospholipid bilayer. How do phospholipids contribute to the fluid mosaic model?
Phospholipids provide the fluid matrix in which proteins and other molecules are embedded and can move. What is the role of estrogen and testosterone in the body?
Estrogen and testosterone are steroid hormones that regulate sexual development and function. Why are lipids considered macromolecules?
Lipids are large, complex molecules essential for biological structure and function. What is the function of the phosphate group in a phospholipid?
The phosphate group forms the hydrophilic head, allowing interaction with water. How do waxes help plants survive in dry environments?
Waxes form a protective layer that reduces water loss from plant surfaces. What is the relationship between cholesterol and membrane rigidity?
Cholesterol increases membrane rigidity and stability. What is the difference between saturated and unsaturated fats?
Saturated fats have no double bonds in their hydrocarbon chains, while unsaturated fats have one or more double bonds. Why are oils liquid at room temperature?
Oils are liquid at room temperature due to the presence of unsaturated fatty acids, which prevent tight packing. What is the main function of steroids in the body?
Steroids function as hormones and components of cell membranes. How do phospholipids form a bilayer in water?
Phospholipids arrange with hydrophilic heads facing water and hydrophobic tails facing inward, forming a bilayer.
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