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Module 2 Exam LO

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Terms in this set (29)

  • What is the smallest unit of life?
    A cell is the smallest unit of life.
  • Compare cytoplasm and cytosol.
    Cytoplasm includes the cytosol and organelles; cytosol is the fluid portion inside the cell.
  • What are the general roles of the plasma membrane, cytoplasm, and nucleus?
    The plasma membrane controls entry/exit of substances, cytoplasm houses organelles, and the nucleus contains genetic material.
  • How does cell shape affect surface-to-volume ratio?
    Changes in size or shape alter the surface-to-volume ratio, affecting exchange rates; e.g., microvilli increase surface area for absorption.
  • Define apoptosis.
    Apoptosis is programmed cell death, a controlled process to remove damaged or unnecessary cells.
  • Describe the chemical composition of the plasma membrane.
    The plasma membrane is composed of lipids (phospholipids, cholesterol), proteins, and carbohydrates, arranged in a fluid mosaic model.
  • How do lipids and proteins influence membrane permeability?
    Lipid bilayer provides a barrier; membrane proteins regulate selective permeability by forming channels and receptors.
  • List functions of plasma membrane proteins.
    Functions include structural support, receptors for signaling, and channels for molecule transport.
  • Compare intracellular fluid and extracellular fluid.
    Intracellular fluid is inside cells; extracellular fluid surrounds cells. They differ in ion composition and solute concentration.
  • Why is selective permeability important?
    Selective permeability maintains homeostasis by controlling substance movement into and out of the cell.
  • Give examples of permeable and impermeable molecules to the cell membrane.
    Permeable: small nonpolar molecules like O2, CO2; Impermeable: large or charged molecules like proteins and ions.
  • What types of gradients exist across body membranes?
    Concentration, osmotic, pressure, and electrical gradients exist across membranes.
  • What factors affect the rate of diffusion across membranes?
    Rate depends on concentration gradient, surface area, solubility, and molecular size, as described by \(\text{Fick's Law}\).
  • Compare active and passive transport.
    Passive transport requires no energy and moves substances down gradients; active transport requires energy to move substances against gradients.
  • Identify types of membrane transport.
    Types include simple diffusion, facilitated diffusion, osmosis (passive), and primary/secondary active transport.
  • Differentiate leak and gated ion channels.
    Leak channels are always open; gated channels open in response to ligands, voltage changes, or mechanical stimuli.
  • How to predict if a solution is hypotonic, isotonic, or hypertonic?
    Compare solution osmolarity to cell; hypotonic causes swelling, isotonic causes no change, hypertonic causes shrinking.
  • Compare exocytosis, endocytosis, and phagocytosis.
    Exocytosis expels materials; endocytosis brings materials in; phagocytosis engulfs large particles.
  • Define resting membrane potential (RMP).
    RMP is the voltage difference across the plasma membrane when the cell is at rest, typically around -70 mV.
  • What establishes the membrane potential?
    Ion concentration gradients and selective membrane permeability establish membrane potential.
  • Define electrochemical gradient.
    An electrochemical gradient combines concentration and electrical gradients influencing ion movement.
  • How does the sodium-potassium ATPase pump maintain RMP?
    It pumps 3 Na+ out and 2 K+ in using ATP, maintaining ion gradients essential for RMP.
  • What are cell adhesion molecules?
    Proteins that allow cells to interact with their environment and other cells.
  • Roles of membrane receptors and G protein–coupled receptors?
    Membrane receptors detect signals; G protein–coupled receptors transmit signals inside the cell to trigger responses.
  • Define organelle.
    An organelle is a specialized structure within a cell that performs a specific function.
  • Name major intracellular organelles and their functions.
    Examples: mitochondria (energy), ER (protein/lipid synthesis), Golgi (processing), lysosomes (digestion).
  • Describe cytoskeletal elements.
    Microtubules provide structure and transport, microfilaments support shape and movement, intermediate filaments provide mechanical strength.
  • Difference between microvilli and cilia.
    Microvilli increase surface area for absorption; cilia move substances across cell surfaces.
  • Outline the Central Dogma of protein synthesis.
    DNA is transcribed to RNA, which is translated into protein.