Cell Structure & Taxonomy

Cards (56)

  • Cell - fundamental living unit of any organism
  • Metabolism - refers to all of the chemical reactions that occur within a cell.
  • Mutation -accidental changes in the genetical material of cells.
  • Cells Classification
    Prokaryotes and Eukaryotes
  • Prokaryotes - do not have complex system of membranes and organelles; bacteria and archaea
  • Eukaryotes - more complex cells, containing true nucleus.
  • Cell Membrane - Enclosed and keep the cell intact; Composed of large molecules of proteins and phospholipids; Like a “skin”; Regulates passage of substances in and out; Selective permeability
  • Cytoplasm - semi-fluid, gelatinous nutrient matrix; contains the “organelles”
  • Nucleus Components
    Nucleoplasm, Nuclear Membrane, Chromosomes, Nucleolus
  • Nucleus - command center or what controls the functions of the entire cell.
  • Nucleoplasm – gelatinous matrix or base material of the nucleus
  • Nuclear membrane – “skin” around the nucleus, contains holes
  • Chromosomes – consist of linear DNA molecules where GENES are located
  • Endoplasmic Reticulum - Highly convoluted system of membranes that are interconnected to form a transport network tubules and flattened sacs within the cytoplasm.
  • Ribosomes - 18 to 22 nm in diameter; consists of rRNA; play important part in protein synthesis
  • Golgi Apparatus - Packages newly synthesized proteins into small, membrane-enclosed vesicles for storage within the cellar export outside the cell (exocytosis).
  • Lysosomes - –contain lysozyme and other digestive enzymes that break down foreign material taken in by the cell
  • Peroxisomes - where hydrogen peroxide is both generated and broken down
  • Mitochondria - Where most of the ATP (energy carrying molecules) are formed by cellular respiration
  • Plastids - Contains various photosynthetic pigments
  • Chloroplasts – one type of plastid, contain a green, photosynthetic pigment called chlorophyll
  • Cytoskeleton - system of fibers present throughout the cytoplasm; Strengthen, support and stiffen the cell, giving its shape.
  • Microtubules - slender, hallow tubules (tubulins)
  • Microfilaments – Slender, thread-like contractile structures which facilitate cell contraction
  • Cell Wall - External structures that provide rigidity, shape, and protection.
  • Cellulose -polysaccharide, present in algae and plants
  • Chitin - present in fungi and exoskeleton of arthropods
  • Flagella – relatively long, thin structure, the organelle of locomotion.
  • Cilia - tend to be more shorter (hair-like), thinner and more numerous
  • Prokaryotic Cell Structure
    Chromosome (Bacterial Nucleoid) - Consists of a single, long, super coiled, circular DNA molecule; Serves as the control center of the bacterial cell.
  • Prokaryotic Cell Structure
    Plasmid - Small, circular molecules of double-stranded DNA that are not part of the chromosome; Extrachromosomal DNA; May contain 10 to hundred genes; May or may not be present in bacterial cell.
  • Cytoplasmic Particles - Many tiny particle in the bacterial cytoplasm; Most of these are clusters of ribosomes-polyribosomes or polysomes
  • Bacterial Cell Wall (Prokaryotic) - Rigid exterior cell wall that defines the shape of bacteria.
  • Bacterial Cell Wall
    Consist of a complex macromolecule known as Peptidoglycan (murein) – only found in bacteria
  • Gram positive bacteria - thick layer
  • Gram negative bacteria- thinner layer
  • Gram Stain - The most widely used procedure for staining bacteria; Developed over a century ago by Dr. Hans Christian Gram
  • Steps in Staining
    1. Crystal Violet
    2. Iodine (Mordant)
    3. Alcohol (Decolorizer)
    4. Safranin (Counterstain)
  • Glycocalyx - Slimy, gelatinous material produced by the cell membrane and secreted outside the cell wall.
  • SLIME LAYER- not highly organized and is not firmly attached to the cell wall. Enables certain bacteria to glide along solid surfaces