Flashcards on Biomembrane Structure, Function, and Transport
Biomembrane Structure, Function, & Transport: A Student Guide
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Biomembranes
17 cards
Card 1
Question: List the main functions of biomembranes in a cell.
Answer: Serve as selective barriers, facilitate cell signaling, enable transport of ions and molecules, and provide structural support.
Card 2
Question: Is membrane permeability the same across all organelles and cellular structures?
Answer: No. There is a difference in membrane permeability among various organelles and structures.
Card 3
Question: Are all organelles surrounded by a single lipid bilayer? Give examples.
Answer: No. Some organelles have double membranes (e.g., nucleus), others have none; not every organelle is enveloped by a single lipid bilayer.
Card 4
Question: Where in the human body are lipid monolayers found instead of bilayers?
Answer: On lipid droplets (fat storage) and as part of lung surfactant.
Card 5
Question: What role does a lipid monolayer play on lipid droplets and in lung surfactant?
Answer: It stabilizes the interface between hydrophobic lipids and the aqueous cytosol or air.
Card 6
Question: Why is a monolayer sufficient for lipid droplets and a bilayer redundant there?
Answer: Because the interior is entirely hydrophobic (triacylglycerols), so a second inner layer of polar heads would be redundant and energetically unfavorab
Card 7
Question: If a lipid bilayer were to substitute the tympanic membrane, how would its phospholipids be oriented?
Answer: Phospholipids would orient with hydrophobic tails facing each other and hydrophilic heads facing the exterior and interior aqueous environments.
Card 8
Question: Could a lipid bilayer alone perform the mechanical role of the tympanic membrane (eardrum)? Why or why not?
Answer: No. A lipid bilayer is a fluid, nanometers-thick structure and lacks the mechanical strength and elasticity provided by cells and extracellular matrix
Card 9
Question: What is the real-life spatial shape of a lipid bilayer, compared to the simplified flat depiction?
Answer: It forms closed, curved surfaces such as spheres or tubes to avoid exposed edges rather than being a flat linear entity.
Card 10
Question: What does functional asymmetry of a membrane mean?
Answer: The two leaflets of the bilayer have different lipid compositions and different associated proteins, allowing the inside and outside of the membrane t