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Anatomy & Physiology: Cell Structure and Organelles

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Termini in questo insieme (20)

  • What are the three basic parts of a generalized human cell?
    Plasma membrane (flexible outer boundary), cytoplasm (intracellular fluid with organelles), and nucleus (DNA-containing control center).
  • What is the primary function of mitochondria?
    Mitochondria produce most of the cell's energy molecules (ATP) via aerobic cellular respiration.
  • Describe the structure of mitochondria.
    Double membrane organelle; inner membrane has folds called cristae embedded with proteins for respiration; contains its own DNA, RNA, and ribosomes.
  • What are ribosomes and their two forms?
    Nonmembranous organelles for protein synthesis; free ribosomes synthesize soluble proteins in cytosol, membrane-bound ribosomes synthesize proteins for membranes or export.
  • What are the two types of endoplasmic reticulum (ER) and their functions?
    Rough ER has ribosomes; synthesizes proteins for secretion or membranes. Smooth ER lacks ribosomes; involved in lipid metabolism, steroid synthesis, detoxification, glycogen breakdown, and calcium storage.
  • What is the role of the Golgi apparatus?
    Modifies, concentrates, and packages proteins and lipids from rough ER into vesicles for transport or secretion.
  • What are lysosomes and their functions?
    Membranous sacs with digestive enzymes that break down bacteria, viruses, toxins, nonfunctional organelles, glycogen, and release calcium from bone.
  • What is the cytoskeleton and its three main components?
    Network of protein rods providing cell structure and movement; includes microfilaments, intermediate filaments, and microtubules.
  • What are microfilaments composed of and their function?
    Thinnest cytoskeletal elements made of actin; involved in cell motility, shape changes, endocytosis, and exocytosis.
  • What is the function of intermediate filaments?
    Intermediate-sized cytoskeletal fibers that provide tensile strength and resist pulling forces on the cell.
  • Describe microtubules and their role in the cell.
    Largest cytoskeletal elements; hollow tubes of tubulin; determine cell shape and organelle distribution.
  • What is the centrosome and what does it contain?
    Microtubule organizing center near the nucleus; contains a granular matrix and a pair of centrioles.
  • What are centrioles and their functions?
    Barrel-shaped microtubular organelles that organize mitotic spindle during cell division and form bases of cilia and flagella.
  • What are cilia and their function?
    Short, motile cellular extensions that move substances across cell surfaces, e.g., mucus in respiratory tract.
  • What is a flagellum and which human cell has it?
    Longer motile extension that propels the whole cell; only human cell with flagellum is sperm.
  • What are the three main structures of the nucleus?
    Nuclear envelope, nucleoli, and chromatin.
  • Describe the nuclear envelope.
    Double membrane barrier enclosing nucleoplasm; outer membrane continuous with rough ER and studded with ribosomes; contains nuclear pores for substance exchange.
  • What is the function of nucleoli?
    Dark-staining bodies in nucleus involved in ribosomal RNA synthesis and ribosome subunit assembly.
  • What is chromatin composed of?
    30% DNA, 60% histone proteins, and 10% RNA; chromosomes are condensed chromatin for protection during cell division.
  • What is the cell theory?
    Cells are the smallest unit of life; all organisms are made of cells; cells arise only from other cells.