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Anatomy & Physiology: Cell Structure and Function

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Terms in this set (39)

  • What are the fundamental units of life?
    Cells are the fundamental units of life, carrying out all functions necessary for life.
  • What are the common characteristics of living organisms?
    Cellular composition, metabolism (anabolism and catabolism), growth, excretion, responsiveness, movement, and reproduction.
  • What are the two main types of cells?
    Prokaryotic cells (no nucleus) and eukaryotic cells (with nucleus).
  • Define anabolism and catabolism.
    Anabolism builds molecules and stores energy; catabolism breaks down molecules and releases energy.
  • What is an oxidation-reduction (redox) reaction?
    A chemical reaction where electrons transfer between substances, changing their oxidation states.
  • Explain oxidation and reduction in redox reactions.
    Oxidation is loss of electrons; reduction is gain of electrons.
  • What are oxidizing and reducing agents?
    An oxidizing agent gains electrons and causes oxidation; a reducing agent loses electrons and causes reduction.
  • What are the four basic components of most animal cells?
    Plasma membrane, cytoplasm (cytosol and organelles), cytoskeleton, and nucleus.
  • What is the function of the plasma membrane?
    It isolates the cell, provides structural support, communicates with other cells, regulates transport, and identifies the cell.
  • What is the difference between cytosol and cytoplasm?
    Cytosol is the fluid inside the cell; cytoplasm includes cytosol plus organelles and cytoskeleton.
  • Describe the phospholipid bilayer structure.
    A double layer with hydrophilic polar heads facing water and hydrophobic nonpolar tails facing inward, forming a barrier.
  • What is the Fluid Mosaic Model of the plasma membrane?
    A model describing the membrane as a fluid combination of phospholipids, proteins, cholesterol, and carbohydrates forming a mosaic.
  • What are integral and peripheral membrane proteins?
    Integral proteins span the membrane; peripheral proteins are attached to one side of the membrane.
  • Name the main functions of membrane proteins.
    They act as channels, carriers, receptors, enzymes, structural supports, and linkers.
  • What is selective permeability of the plasma membrane?
    The membrane allows some substances to pass while restricting others, based on size, charge, and solubility.
  • Define passive transport and give examples.
    Movement of substances down their concentration gradient without energy, including diffusion, facilitated diffusion, and osmosis.
  • What is osmosis?
    The passive movement of water across a selectively permeable membrane from low to high 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?
    Movement of substances against their concentration gradient using energy (ATP) and carrier proteins called pumps.
  • Describe the sodium-potassium pump.
    It moves 3 Na+ out and 2 K+ into the cell using 1 ATP, maintaining membrane potential essential for nerve and muscle function.
  • What are vesicular transport processes?
    Active transport using vesicles, including endocytosis (into cell) and exocytosis (out of cell).
  • What is receptor-mediated endocytosis?
    A selective form of endocytosis where ligands bind to specific receptors to form vesicles with high concentrations of substances.
  • What are membrane-bound organelles?
    Organelles enclosed by phospholipid bilayers, such as mitochondria, peroxisomes, endoplasmic reticulum, Golgi apparatus, and lysosomes.
  • What is the function of mitochondria?
    Produce most of the cell's ATP through oxidative catabolism; contain their own DNA and enzymes.
  • What do peroxisomes do?
    Use oxygen to oxidize toxic substances, break down fatty acids, and synthesize certain phospholipids.
  • What is the role of ribosomes?
    Sites of protein synthesis; found free in cytosol or bound to rough ER.
  • What is the endomembrane system?
    A group of organelles (ER, Golgi, lysosomes, plasma membrane) that synthesize, modify, and transport cellular substances.
  • What is the cytoskeleton and its functions?
    A network of protein filaments that maintain cell shape, support membranes and organelles, and enable movement.
  • Name the three types of cytoskeletal filaments.
    Actin filaments (microfilaments), intermediate filaments, and microtubules.
  • What is the nucleus and its main components?
    The control center containing DNA, surrounded by the nuclear envelope, with nucleoplasm and nucleolus for RNA synthesis.
  • What is chromatin and how does it relate to chromosomes?
    Chromatin is DNA and proteins in a loose form; it condenses into chromosomes during cell division.
  • What is protein synthesis?
    The process of making proteins from DNA via transcription (DNA to mRNA) and translation (mRNA to protein).
  • What are the three types of RNA involved in protein synthesis?
    mRNA carries the code, tRNA delivers amino acids, and rRNA forms the ribosome structure.
  • What is the cell cycle?
    An ordered series of phases (interphase and mitosis) through which a cell grows and divides.
  • What are the main phases of interphase?
    G1 (growth), S (DNA synthesis), and G2 (preparation for mitosis).
  • What happens during mitosis?
    Division of genetic material into two identical sets through prophase, metaphase, anaphase, and telophase.
  • What are cell cycle checkpoints?
    Control points that regulate progression through the cell cycle to ensure proper division.
  • What is anchorage dependence and density-dependent inhibition?
    Mechanisms that regulate cell division by requiring attachment to a surface and stopping division when cells contact each other.
  • How do cancer cells differ in cell cycle control?
    They lack anchorage dependence and density-dependent inhibition, leading to uncontrolled division and tumor formation.