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Anatomy & Physiology: Cell Structure and Function

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Terms in this set (28)

  • What are the three basic components of most animal cells?
    Plasma membrane, cytoplasm (including cytosol, organelles, cytoskeleton), and nucleus.
  • What is the primary function of the plasma membrane?
    It isolates the cell from its surroundings, provides structural support, communicates with other cells, regulates transport, and identifies the cell.
  • What are the two fluid compartments defined by the plasma membrane?
    Intracellular fluid (cytosol) inside the cell and extracellular fluid (ECF) outside the cell.
  • What are the main components of the cytoplasm?
    Cytosol (watery gel), organelles (specialized molecular machines), and cytoskeleton (protein filament network).
  • What is the role of the nucleus in the cell?
    Contains most of the cell's DNA and is the site for RNA production, controlling cellular functions by coding and creating proteins.
  • Describe the structure of the phospholipid bilayer.
    Composed of hydrophilic polar phosphate heads facing water and hydrophobic nonpolar fatty acid tails facing inward, forming a barrier between ECF and cytosol.
  • What is the Fluid Mosaic Model of the plasma membrane?
    A model describing the plasma membrane as a dynamic mosaic of phospholipids, proteins, lipids, and carbohydrates that move laterally, providing fluidity.
  • What are the two main types of membrane proteins based on location?
    Integral proteins span the membrane (transmembrane if both sides), and peripheral proteins are found on one side.
  • List the main functions of membrane proteins.
    Channels for passage, carriers for transport, receptors for ligand binding, enzymes for catalysis, structural support, and linkers for cell adhesion.
  • How does the SARS-CoV-2 virus enter human cells?
    The virus spike protein binds to the ACE2 receptor, an integral membrane protein, allowing viral entry and replication.
  • What is the role of cholesterol in the plasma membrane?
    It stabilizes the membrane structure during temperature changes.
  • Define passive transport and its types.
    Movement of substances across the membrane without energy, including simple diffusion, facilitated diffusion, and osmosis.
  • What is osmosis?
    Movement of water across a selectively permeable membrane from a solution with lower solute concentration to one with higher solute concentration.
  • Explain tonicity and its types.
    Isotonic: equal solute concentration; Hypertonic: higher solute outside, cell shrinks; Hypotonic: lower solute outside, cell swells.
  • What is active transport?
    Energy-requiring process where solutes move against their concentration gradient using ATP and carrier proteins called pumps.
  • Describe the Sodium-Potassium Pump function.
    Moves 3 Na+ ions out and 2 K+ ions into the cell against their gradients using ATP hydrolysis.
  • What is secondary active transport?
    Uses energy from a concentration gradient created by primary active transport to move another substance against its gradient, often via symport or antiport.
  • What is endocytosis and its types?
    Process of bringing substances into the cell via vesicles; includes phagocytosis (large particles), pinocytosis (fluid), and receptor-mediated endocytosis (specific ligands).
  • What is exocytosis?
    Process of releasing substances from the cell by fusion of transport vesicles with the plasma membrane.
  • Name the three types of cytoskeletal filaments and one key function each.
    Actin filaments: support and cell shape; Intermediate filaments: mechanical strength; Microtubules: organelle movement and cell structure.
  • What are microvilli, cilia, and flagella?
    Microvilli increase surface area; cilia move substances with coordinated beating; flagella propel whole cells with whiplike motion.
  • What is the function of the rough and smooth endoplasmic reticulum?
    Rough ER modifies and folds proteins; Smooth ER stores calcium, detoxifies substances, and synthesizes lipids.
  • What is the role of lysosomes?
    Contain enzymes to digest macromolecules, degrade worn organelles, and destroy bacteria; function best in acidic pH.
  • What is the process of protein synthesis?
    Involves transcription (DNA to mRNA) and translation (mRNA to polypeptide) followed by posttranslational modification.
  • What are the main phases of the cell cycle?
    Interphase (G1, S, G2 phases) for growth and DNA replication, and M phase for mitosis and cytokinesis.
  • What happens during mitosis?
    Chromosomes condense, align, separate, and the cell divides into two genetically identical daughter cells.
  • What is apoptosis?
    Programmed cell death to remove damaged or unneeded cells.
  • What distinguishes benign from malignant tumors?
    Benign tumors remain localized; malignant tumors invade tissues and can metastasize.