Lipids quiz #2 Flashcards
Lipids quiz #2
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What is the significance of the amphipathic nature of phospholipids?
The amphipathic nature allows phospholipids to form membranes that separate cellular compartments. What is the function of the hydrophobic tails in a phospholipid bilayer?
The hydrophobic tails form the interior of the bilayer, creating a barrier to water-soluble substances. How do lipids differ from carbohydrates in solubility?
Lipids are hydrophobic and insoluble in water, while carbohydrates are generally hydrophilic and soluble. What is the role of the glycerol molecule in a phospholipid?
Glycerol links the phosphate group to the fatty acid tails in a phospholipid. Why are cell membranes described as 'mosaic'?
Cell membranes are called 'mosaic' because they contain various proteins and molecules embedded in the phospholipid bilayer. What types of molecules can freely cross the cell membrane?
Small nonpolar molecules, such as oxygen and carbon dioxide, can freely cross the membrane. What is the function of carbohydrates attached to membrane proteins and lipids?
They are involved in cell recognition and signaling. How do embedded proteins contribute to membrane function?
They facilitate transport, communication, and structural support. What is the main difference between waxes and other lipids?
Waxes are long-chain fatty acids linked to alcohols, making them solid and water-repellent. What is the biological importance of the hydrophobic effect?
It drives the formation of membranes, essential for cell compartmentalization. How does the structure of phospholipids enable membrane formation?
Their amphipathic nature causes them to self-assemble into bilayers in water. What is the function of the plasma membrane in cells?
It acts as a selective barrier, controlling entry and exit of substances. What is the role of membrane proteins in transport?
They help move substances across the membrane that cannot pass through the lipid bilayer directly. Why are lipids not considered polymers?
Lipids are not made of repeating monomer units like polymers. What is the function of the hydrophilic head in a phospholipid?
It interacts with the aqueous environment inside and outside the cell. How do lipids contribute to energy storage?
Lipids store energy in their hydrocarbon chains, providing more energy per gram than carbohydrates. What is the significance of cholesterol in animal cell membranes?
Cholesterol modulates membrane fluidity and stability in animal cells. What is the main function of triglycerides?
Triglycerides store energy for long-term use in animals and plants. How do phospholipids contribute to membrane fluidity?
Their movement within the bilayer allows the membrane to remain flexible and dynamic. What is the difference between a phospholipid and a triglyceride?
A phospholipid has two fatty acid tails and a phosphate group, while a triglyceride has three fatty acid tails and no phosphate group. What is the function of the cell membrane in maintaining homeostasis?
It regulates the internal environment by controlling substance movement. How do steroids differ structurally from fats and oils?
Steroids have a four-ring structure, while fats and oils have long hydrocarbon chains. What is the role of the hydrophobic tails in preventing water passage?
They create a barrier that blocks water-soluble substances from crossing the membrane. Why are phospholipids essential for life?
They form the basic structure of cell membranes, enabling compartmentalization and life processes. What is the function of the plasma membrane in communication?
It contains proteins and carbohydrates involved in cell signaling and recognition. How do lipids contribute to waterproofing in organisms?
Waxes and certain lipids form protective, water-repellent layers. What is the main difference between animal and plant energy storage lipids?
Animals store energy as fats (solid), while plants store energy as oils (liquid). What is the function of the hydrophobic core in the phospholipid bilayer?
It acts as a barrier to most water-soluble substances. How do phospholipids self-assemble in water?
They spontaneously form bilayers with hydrophilic heads facing water and hydrophobic tails facing inward. What is the role of membrane carbohydrates in immunity?
They help cells recognize each other and distinguish self from non-self. What is the function of the cell membrane in transport?
It regulates the movement of substances into and out of the cell. How do lipids differ from proteins in structure and function?
Lipids are hydrophobic molecules mainly for energy storage and membranes, while proteins are polymers with diverse functions. What is the importance of membrane fluidity for cell function?
Fluidity allows for membrane flexibility, protein movement, and proper cell function. What is the function of the hydrophilic head group in phospholipids?
It interacts with the aqueous environment, stabilizing the membrane surface. How do lipids contribute to hormone production?
Steroid lipids serve as precursors for hormones like estrogen and testosterone. What is the main function of the phospholipid bilayer?
It forms a selective barrier that separates the cell from its environment. How do membrane proteins assist in cell signaling?
They act as receptors that transmit signals from outside to inside the cell. What is the role of glycolipids in the cell membrane?
Glycolipids are involved in cell recognition and communication. Why are lipids important for insulation in animals?
Lipids, especially fats, provide thermal insulation by storing energy and reducing heat loss. What is the function of the hydrophobic region in the cell membrane?
It prevents free passage of polar and charged molecules.
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