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Anatomy & Physiology: Cell Biology and Histology

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Termini in questo insieme (30)

  • 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, while 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, the 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?
    Lipids form a hydrophobic barrier; proteins create channels and receptors, determining what passes through the membrane.
  • 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 and 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 channels.
    Leak channels are always open; gated channels open in response to ligands, voltage changes, or mechanical stimuli.
  • Predict tonicity of a solution relative to a human cell.
    Hypotonic solutions have lower solute concentration, causing cell swelling; isotonic solutions have equal concentration; hypertonic solutions cause cell shrinkage.
  • Compare exocytosis, endocytosis, and phagocytosis.
    Exocytosis expels materials; endocytosis engulfs substances; phagocytosis is a form of endocytosis for large particles.
  • Define resting membrane potential (RMP).
    RMP is the electrical potential difference across the membrane of a resting cell, typically around -70 mV.
  • How do ion gradients and membrane permeability establish membrane potential?
    Ion concentration differences and selective permeability create electrical charge differences across the membrane.
  • Define electrochemical gradient.
    An electrochemical gradient combines concentration and electrical gradients influencing ion movement.
  • Role of sodium-potassium ATPase in RMP?
    The pump moves 3 Na+ out and 2 K+ in, maintaining ion gradients essential for RMP.
  • What are cell adhesion molecules?
    Proteins that allow cells to attach to each other and the extracellular matrix, facilitating communication and structure.
  • 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 subunit within a cell with a specific function.
  • Functions of major intracellular organelles?
    Examples: mitochondria produce energy; ribosomes synthesize proteins; lysosomes digest waste.
  • 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 structure of the nucleus.
    The nucleus has a double membrane (nuclear envelope), nucleoli for ribosome assembly, and chromatin containing DNA.
  • Define genetic code, gene, transcription, and translation.
    Genetic code: DNA instructions; gene: DNA segment coding for protein; transcription: DNA to RNA; translation: RNA to protein.