biology chapter 4

• The cytoplasm is the gel-like substance inside the cell that contains various organelles and is the site of many cellular processes.
• A membrane-enclosed structure with a specialized

  Organelles
• Organisms are either single-celled (prokaryotes, protists) or multi-celled (plants, Animals, most fungi)
• Cells were first described by Robert Hooke


  1665
• Cell theory


  All living things are composed of cells, all cells come from other cells
• The Two Major Categories of Cells

  • Prokaryotic cells (Bacteria and Archaea)
  • Eukaryotic cells (protists, plants, fungi, and animals)
• Cells


  • Bounded by a thin plasma membrane
  • Have a thick, jelly-like fluid called cytosol
  • Have one or more chromosomes carrying genes made of DNA
  • Have ribosomes that build proteins
• Prokaryotic cells are older than eukaryotic cells
• Prokaryotic cells


  Usually smaller and simpler in structure than eukaryotic cells
• Eukaryotic cells


  • Have membrane-enclosed organelles that perform specific functions
  • The most important organelle is the nucleus, which houses most of the cell's DNA and is surrounded by a double membrane
• Prokaryotic cell


  Lacks a nucleus, has DNA coiled into a nucleoid region not partitioned from the rest of the cell by membranes
• Eukaryotic cells are fundamentally similar
• Cytoplasm


  The region between the nucleus and plasma membrane, consisting of various organelles suspended in the liquid cytosol
• Plasma membrane


  Separates the living cell from its nonliving surroundings, composed mostly of lipids and proteins
• Phospholipid bilayer


  The two-layered membrane structure of the plasma membrane
• Fluid mosaic


  The plasma membrane, with its diversity of proteins moving freely past one another
• Plant cell walls


  • Made of cellulose, protect cells, maintain cell shape, keep cells from absorbing too much water
• Animal cells


  • Lack cell walls, typically have an extracellular matrix that helps hold cells together in tissues and protects/supports them
• Cytoskeleton


  A network of fibers extending throughout the cytoplasm, providing mechanical support and helping maintain cell shape
• Cilia and flagella


  • Motile appendages that aid in movement, with cilia being shorter and more numerous than flagella
• Types of Organelles found in Eukaryotic Cells


  • Know the name, function, and location for each organelle
• Nucleus


  The chief executive of the cell, storing information to produce proteins
• Proteins do most of the work of the cell
• Ribosomes are responsible for protein synthesis</b>
• Endomembrane system


  Interconnected membranous organelles including the nuclear membrane, endoplasmic reticulum, Golgi apparatus, lysosomes, vesicles, and cell membrane
• Endoplasmic reticulum (ER)


  • One of the main manufacturing facilities in a cell, composed of smooth and rough ER
• Rough ER


  Has ribosomes that produce membrane proteins and secretory proteins, dispatching some products via transport vesicles
• Smooth ER


  Lacks surface ribosomes, produces lipids including steroids, helps detoxify drugs
• Golgi apparatus


  • Works in partnership with the ER to receive, refine, store, and distribute chemical products of the cell
• Lysosome


  A membrane-bound sac of digestive enzymes found in animal cells, can break down large molecules and destroy harmful bacteria/damaged organelles
• Vacuoles


  • Large sacs of membrane that bud from the ER, Golgi apparatus, or plasma membrane, with contractile vacuoles in protists and central vacuoles in plant cells
• Cells require a continuous energy supply to perform the work of life
• Chloroplasts


  • Unique to the photosynthetic cells of plants and algae, the organelles that perform photosynthesis
• Mitochondria


  • The organelles of cellular respiration, found in almost all eukaryotic cells, produce ATP from the energy of food molecules
• Extracellular matrix (ECM)


  The material outside of cells that provides structural support and regulates cell behavior, composed of proteins and carbohydrates such as collagen, elastin, and proteoglycans
• Cytoplasm


  The material inside a cell, excluding the nucleus, made up of organelles and cytosol where most of the cell's metabolic processes take place