biology chapter 20

  1. the three shapes of prokaryotes
    • a rod shape (bacillus)
    • a sphere shape (coccus)
    • a spiral shape (spirillum)
  2. two groups of prokaryotes
    • archaea
    • bacteria
  3. bacterial dna
    a single chromosome clustered in a mass called a nucleotide
  4. plasmids
    small extra loop of dna
  5. peptidoglycan
    a protein-carb compound that makes up the bacterial cell wall.

    this wall allows for the use of the gram stain
  6. gram positive
    have a thick layer of peptidoglycan and no outer membrane. its stain is violet/purple
  7. gram negative
    have a thin layer of peptidoglycan & have an outer membrane its stain is pink
  8. photoautotrophs
    organisms that get their energy from sunlight through photosynthesis
  9. chemoautotrphs
    the only organisms that can get their energy from inorganic sources.

    use molecules that contain sulfur or nitrogen & simple organic molecules

    in the presence of hydrogen rich chemicals, chemoautotrophic bacteria can form all of their own amino acids and proteins.
  10. heterotrophs
    most prokaryotes are this

    get both energy & nutrition form other organisms
  11. binary fission
    the means in which prokaryotes reproduce

    a sexual
  12. forming new genetic combinations (prokaryotes)
    conjugation~ when 2 bacteria exchange genetic material

    transformation~ when bacteria take up dna fragments from their enviroment.

    transduction~ when genetic material, such as a plasmid, is transferred by a virus. plasmids often convey antibiotic resistance
  13. endospores
    thick wall structures

    help bacteria survive harsh conditions

    they form inside the bacteria they surround the dna and a small bit of cytoplasm

    show no signs of life & can be revived after hundreds of years.
  14. virus
    pieces of nucleic acid contained in a protein coat

    not considered to be living
  15. two structures characteristic of all viruses
    nucleic acid & a capsid
  16. capsid
    the protein coat of a virus encloses its genetic material.

    viruses recognize their hosts by specific proteins on a host cell's surface. the proteins on the host cell have to match proteins on the capsid of the virus.
  17. envelope
    a membrane surrounding the capsid.

    gives the membrane an overall spherical shape even if capsid is not.

    its studded w/ receptors that help the virus enter cells. its made up of proteins, lipids, & glycoproteins
  18. bacteriophages
    viruses that infect bacteria

    aka phages

    have a complicated structure
  19. virus reproduction
    lytic and lysogenic cycle.

    lytic~ the cycle of viral infection, reproduction, & cell destruction

    lysogenic~ host shares viral dna. host cell is not destroyed.
  20. prophage
    when viral dna becomes part of its host cell's dna
  21. temperate virus
    a virus whose reproduction includes the lysogenic cycle
  22. nonliving particles that are able to reproduce & cause disease
    viroids & prions
  23. viroid
    a single strand of rna that has no capsid.

    rna of virus < rna o virus

    disrupt host cell's regulation of growth
  24. prion
    misshapen versions of proteins that are found in the brain.
  25. bacteria and environment
    vital role in all ecosystems

    produce oxygen, makes nitrogen available, & helps decompose dead organisms. many form symbiotic relations
  26. bacteria, viruses, & research
    important in genetic reasearch

    their genetic mataerial is easily studied

    valuable info on dna replication, transcription, and translation

    used in gene therapy
  27. koch's postulates
    technique for diagnosing the cause of an infection

    • 1) pathogen must be found in an animal w/ the disease & not in a healthy animal
    • 2) pathogen must be isolated from the sick animal & grown in a laboratory culture
    • 3) when injected into a healthy animal, the animal must contract the disease
    • 4) pathogen from 2nd animal must be the same as the original pathogen
  28. pathogenic bacteria ways to cause disease
    by producing toxins

    destroying body tissues( by producing enzymes that break down the host's tissues into nutrients that the bacteria can use)
  29. toxins
    the most common way that bacteria cause disease is by producing poisonous chemicals
  30. antibiotics
    chemicals that inhibit the growth of or kill micro-organisms
  31. the spread of antibiotic resistance
    spreads when sensitive populations of bacteria are killed by antibiotics. as a result resistant bacteria thrive
Card Set
biology chapter 20
biology chapter 20