VPHY 3100 Test 1 Questions and Answers Solved Correctly Latest Update

VPHY 3100 Test 1 Questions and Answers Solved Correctly Latest Update Plasma membrane, nucleus, cytoplasm - Answers What are the 3 parts of a eukaryotic cell? Phospholipid bilayer - Answers What is the main component of the plasma membrane? Hydrophilic (polar) head and hydrophobic (nonpolar) tails - Answers What are the two parts of a phospholipid? : The ability of the membrane to regulate what enters and exits the cell - Answers : What is selective permeability? Gases, small alcohols, urea - Answers : What type of molecules can pass through the phospholipid bilayer by simple diffusion? : Net diffusion of water across a membrane from high to low water concentration - Answers : What is osmosis? The force needed to stop osmosis - Answers : What is osmotic pressure? Total solute concentration (not solute type) - Answers : What determines osmotic pressure? Molarity = moles solute / liter of solution; Molality = moles solute / kg of solvent - Answers What is the difference between molarity and molality? Water moves toward areas of higher total solute concentration - Answers What does "water follows solute" mean ATP - Answers What does a pump (primary active transporter) use for energy? 3 Na⁺ out, 2 K⁺ in - Answers What does a sodium-potassium pump move and in which direction? Movement of net charge across a membrane (e.g., Na⁺/K⁺ pump - Answers What is electrogenic transport? Symporter: moves solutes in same direction; Antiporter: opposite directions - Answers What's the difference between symporter and antiporter? : Nernst potential for potassium (Eₖ) - Answers : What is the resting membrane potential usually close to? The voltage at which an ion is at equilibrium across the membrane - Answers What is the Nernst potential? Charge of the ion and concentration gradient - Answers What determines the Nernst potential? What are the four major receptor types in cell signaling? - Answers What are the four major receptor types in cell signaling? Water, carbohydrates, proteins (e.g., collagen, elastin, proteoglycans) - Answers : What makes up the extracellular matrix (ECM)? Two-thirds - Answers What portion of total body water is intracellular? About 1/5 - Answers What portion of extracellular fluid is blood plasma? Membrane permeable to water, concentration gradient exists, solute is osmotically active - Answers What must be true for osmosis to occur? Facilitated diffusion (passive transport) - Answers What type of transport uses integral membrane proteins but no energy? Pumps, carriers, channels - Answers What are the three classes of transport proteins? Channels and uniporters (some) - Answers Which transport proteins are always passive? Energy released by another ion moving down its gradient - Answers : What are secondary active transporters powered by? Creates a Na⁺ gradient to drive Na⁺-glucose symport - Answers What is the purpose of the Na⁺/K⁺ pump in glucose absorption? Water enters → cell swells (may burst) - Answers : What happens to a cell in a hypotonic solution? Water exits → cell shrinks (crenation) - Answers What happens to a cell in a hypertonic solution? The relative solute concentration of a solution compared to the cell - Answers What is tonicity? Voltage difference across the plasma membrane - Answers What is membrane potential? In the direction that brings membrane potential toward Nernst potential - Answers What direction will ions move if the membrane potential ≠ Nernst potential? Eₓ = (61 / z) × log([X]out / [X]in) - Answers How do you calculate Nernst potential (Eₓ)? : E_Cl⁻ = about -86 mV - Answers What happens if [Cl⁻]out = 130 mM and [Cl⁻]in = 5 mM? Into the cell (until membrane reaches -86 mV) - Answers If resting potential = -70 mV and E_Cl⁻