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General Biology: Cell Structure and Function

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Termini in questo insieme (20)

  • What are the fundamental units of life?
    Cells are the fundamental units of life.
  • What are the main differences between prokaryotic and eukaryotic cells?
    Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have a nucleus and membrane-bound organelles.
  • Name two similarities between animal and plant cells.
    Both have a plasma membrane and contain organelles like the nucleus, mitochondria, and endoplasmic reticulum.
  • What is the plasma membrane and its main function?
    The plasma membrane is a selectively permeable lipid bilayer that controls the movement of substances in and out of the cell.
  • Define diffusion, facilitated diffusion, and osmosis.
    • Diffusion: movement of molecules from high to low concentration.
    • Facilitated diffusion: diffusion via transport proteins.
    • Osmosis: diffusion of water across a selectively permeable membrane.
  • What is the difference between passive and active transport across the plasma membrane?
    Passive transport moves substances down their concentration gradient without energy; active transport requires energy to move substances against the gradient.
  • When do endocytosis and exocytosis occur?
    Endocytosis occurs to bring large molecules into the cell; exocytosis expels materials out of the cell.
  • What is the cell wall and which cells have it?
    The cell wall is a rigid outer layer found mainly in plant, fungal, and bacterial cells that provides structural support and protection.
  • How does the cell wall differ from the plasma membrane?
    The cell wall is rigid and provides support; the plasma membrane is flexible and controls selective permeability.
  • Describe the structure of the nucleus.
    The nucleus is surrounded by a double membrane called the nuclear envelope and contains the nucleolus and chromosomes.
  • What is the function of the nucleolus?
    The nucleolus synthesizes ribosomal RNA and assembles ribosome subunits.
  • How is genetic information transferred from the nucleus to the cytoplasm?
    DNA is transcribed into mRNA in the nucleus, which then moves to the cytoplasm for protein synthesis.
  • What are the differences between rough and smooth endoplasmic reticulum (ER)?
    Rough ER has ribosomes and synthesizes proteins; smooth ER lacks ribosomes and synthesizes lipids and detoxifies substances.
  • What role does the rough ER play in protein synthesis?
    Rough ER synthesizes and modifies proteins destined for secretion or membranes.
  • What is the function of the Golgi apparatus?
    The Golgi apparatus modifies, sorts, and packages proteins for secretion or delivery to other organelles.
  • Why are mitochondria called the powerhouses of the cell?
    Mitochondria generate ATP through cellular respiration, providing energy for cellular activities.
  • What is the structural organization of mitochondria?
    Mitochondria have a double membrane with an inner membrane folded into cristae to increase surface area.
  • What are vacuoles and their functions in plant and animal cells?
    Vacuoles store nutrients, waste, and help maintain turgor pressure in plant cells; in animal cells, they are smaller and involved in storage and transport.
  • What is the cytoskeleton and its main functions?
    The cytoskeleton is a network of protein fibers that provides structural support, aids in cell movement, and organizes organelles.
  • What is the extracellular matrix and its importance?
    The extracellular matrix is a network of proteins and carbohydrates outside the cell that provides structural support and mediates cell communication.