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Cell Structure and Function - Anatomy & Physiology

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Terms in this set (20)

  • What is the Cell Theory?

    The cell is the unit of structure, physiology, and organization in living things. All cells arise from pre-existing cells, and all metabolic events occur within cells.

  • Why are most cells relatively small?

    Cell size is limited due to reliance on diffusion of substances in and out of cells, which is affected by surface area, temperature, concentration gradient, and distance.

  • What are the two main types of microscopes used to study cells?

    Light microscopes use visible light and resolve structures 200 nm apart; electron microscopes use electron beams and resolve structures 0.2 nm apart.

  • What are the main components of the cytoplasm?

    Cytoplasm includes cytosol (water with dissolved solutes), cytoplasmic organelles (metabolic machinery), and inclusions (chemical substances like glycogen granules).

  • Describe the structure of the plasma membrane.

    The plasma membrane is a phospholipid bilayer with embedded proteins, cholesterol, glycolipids, and carbohydrates forming a fluid mosaic model.

  • What are the functions of biological membranes?

    Import/export, compartmentalization, cell signaling, cell and nuclear division, and production of energy intermediates.

  • What are the six functions of membrane proteins?

    Transport, receptors for signal transduction, attachment to cytoskeleton and extracellular matrix, enzymatic activity, intercellular joining, and cell-cell recognition.

  • How do transport proteins assist in membrane transport?

    They provide hydrophilic channels or actively pump substances using ATP to move solutes across the membrane selectively.

  • What is osmosis?

    Osmosis is the net diffusion of water across a membrane toward a higher solute concentration.

  • What is the difference between simple diffusion and facilitated diffusion?

    Simple diffusion moves nonpolar, lipid-soluble substances directly through the bilayer; facilitated diffusion uses carrier or channel proteins for polar molecules.

  • Describe the sodium-potassium pump mechanism.

    ATP phosphorylates the pump, changing its shape to expel Na+ outside and bring K+ inside, maintaining concentration gradients.

  • What is vesicular transport?

    Transport of large particles/macromolecules via exocytosis (out of cell) or endocytosis (into cell), including phagocytosis and receptor-mediated endocytosis.

  • What are the three types of cell junctions?

    Tight junctions (impermeable seals), desmosomes (anchoring 'spot-welds'), and gap junctions (channels allowing molecule passage).

  • What are mitochondria and their function?

    Double-membrane organelles with cristae that produce most of the cell's ATP via aerobic respiration and contain their own DNA and RNA.

  • What is the role of ribosomes?

    Granules of protein and rRNA that synthesize proteins; free ribosomes make cytosolic proteins, membrane-bound ribosomes make proteins for membranes or export.

  • Differentiate rough and smooth endoplasmic reticulum (ER).

    Rough ER has ribosomes for protein synthesis; smooth ER synthesizes lipids, detoxifies drugs, metabolizes glycogen, and stores calcium.

  • What is the function of the Golgi apparatus?

    Modifies, concentrates, and packages proteins from the ER into vesicles for transport or secretion.

  • What are lysosomes and their functions?

    Membranous sacs with digestive enzymes that break down bacteria, viruses, nonfunctional organelles, and bone to release calcium.

  • What is the cytoskeleton?

    A dynamic network of microtubules, microfilaments, and intermediate filaments that provide cell shape, support, and movement.

  • What are centrioles and their role?

    Barrel-shaped organelles near the nucleus that organize the mitotic spindle during cell division and form bases of cilia and flagella.