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The Cell - Anatomy & Physiology

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  • What are the three basic components of most animal cells?

    Plasma membrane, cytoplasm (including cytosol, organelles, cytoskeleton), and nucleus.
  • What is the structure of the plasma membrane?

    A phospholipid bilayer with hydrophilic polar phosphate heads facing water and hydrophobic nonpolar fatty acid tails facing inward.
  • What is the fluid mosaic model of the plasma membrane?

    A model describing the membrane as a fluid combination of phospholipids, cholesterol, and proteins that move laterally within the layer.
  • Name the main functions of membrane proteins.

    Channels, carriers, receptors, enzymes, structural support, and linking adjacent cells.
  • What determines the type of transport across the plasma membrane?

    The substance type, membrane permeability, and concentration gradient inside and outside the cell.
  • What is passive transport?

    Movement of substances across the membrane without energy, including diffusion, facilitated diffusion, and osmosis.
  • What is active transport?

    Energy-requiring transport moving solutes against their concentration gradient using carrier proteins called pumps.
  • Describe primary active transport.

    Direct use of ATP to transport molecules against their concentration gradient, e.g., the Na+/K+ pump.
  • Describe secondary active transport.

    Uses the energy from one molecule moving down its gradient to transport another molecule against its gradient.
  • What is vesicular transport?

    Transport of large particles or fluids using vesicles, including endocytosis (phagocytosis, pinocytosis) and exocytosis.
  • What is phagocytosis?

    A form of endocytosis where cells ingest large particles like bacteria or dead cells, performed by phagocytes.
  • What is the function of mitochondria?

    Produce most of the cell's ATP through oxidative metabolism; contain DNA, enzymes, and ribosomes.
  • What are peroxisomes and their functions?

    Organelles that oxidize toxic substances, break down fatty acids, and synthesize certain phospholipids using hydrogen peroxide.
  • What are ribosomes and their types?

    Sites of protein synthesis; free ribosomes float in cytosol, bound ribosomes attach to membranes.
  • What organelles are part of the endomembrane system?

    Plasma membrane, endoplasmic reticulum, Golgi apparatus, lysosomes, and nuclear envelope.
  • What is the role of the Golgi apparatus?

    Modifies, sorts, and packages proteins and lipids from the ER for transport or secretion.
  • What are lysosomes and their function?

    Membrane sacs with acid hydrolases that digest macromolecules, degrade worn organelles, and destroy bacteria.
  • What are the three types of cytoskeletal filaments?

    Actin filaments (microfilaments), intermediate filaments, and microtubules.
  • What is the nuclear envelope?

    A double phospholipid bilayer membrane with nuclear pores; outer membrane continuous with rough ER.
  • What are the main phases of the cell cycle?

    Interphase (G1, S, G2 phases) for growth and DNA synthesis, and M phase for mitosis and cytokinesis.