Module 2 Summary

• Define capsomere

  • subunit of a capsid <— protein coat “lipid layer”
• why Antibitoics are ineffective against viruses

  • viruses have an envelope for protection and enzymes too.
  • cell wall, ribosomes and DNA replication helps too
• lytic vs lysogenic viruses (types of viruses)

  lytic: kills host

  1. attaches to host
  2. pens
  3. synthesis
  4. assembly
  5. release

  lysogenic: does not kill host

  1.attach

  2. intergrates with chromosomes from host = prophage

  3.lysogenic

  4.prophage excise
• why are viruses not included in domains

  1. non-cellular infectious particles
  2. do not have ssu rrna which is what domains used to caterogries
• how are viruses suspected = cancer

  • due to carrying and promoting ono genes which interface with repression of genes
• characteristics of viruses

  1. NA
  2. characteristics of host
  3. size
  4. arch of capsid
  5. possession of lipid envelope
• Helical vs iscohederal (types of capsids)

  helical: protein capsids, tightly wrapped around the genome

  isoherderal: sym spherical shape
• baltiomore classification is based on

  1. mRNA
  2. production of RNA
  3. genome rep
• ID 3 diseases from animal viruses from diff Baltimore groups

  1. class 6 retrovirus: HIV
  2. class 5: infleuenza and SARS2
  3. class 1: smallpox
• protein coat and the genome of a viruses is called

  • nucleocapsid
• the major component of the gram -ve cell wall is

  • a thin layer of peptidoglycan
• archeal differs from bacteria membrane by

  • the archeal membrane is comprised of isopernoids attached to glycerol phosphate by ether linkage
• the unique characteristic for mycobacterium is

  • mycolic acid
• what is the function of the cyto membrane

  • a barrier separating inside and outside and controls substances
• what happens to freshwater cell in high concentration of saltwater

  • cell wall shrink in size
• active energy

  • requires energy
  • against the concentration gradient
  • aerobic
  • uses proteins to help with transport
• fimbriae

  • attaches bacteria to the surface
• lopotrichous arrangement in flagella

  • flagella in a tuft at one end of the cell
• an archean organism adapts to rising temp within the environment by

  • increasing number of saturated isopreonids within the lipid membrane
• describe the structure of gram -ve cell envelope (cell wall)

  • 3 layers: outer membrane, inner membrane and periplasm
  • thin layer of peptidoglycan
  • lipopolysacchaidres for the outer membrane
  • lipoproteins to connect the cell wall to the outer membrane
• cyto membrane vs outer membrane

  cyto: phosp composition, selectivity permeable, in all bacteria, inner most layer and non toxic

  outer mem: lipopolysaccharides and phosolipids, generally not selectively permeable, only in gram -ve bacteria, outer most layer and can be toxic due to lipid A
• bacterial flagella structure

  1. basal body
  2. hook
  3. filament
• structure and importance of endospores

  • structure: core contains and protects DNA and has low water and is surrounded by several thick layers to help protect the environment extremes
  • importance: provide resistance and survival in adverse conditions for certain bacteria that produce them in high temp, desiccation and toxic chemicals
  • important in: industry for food poisoning and spoilage as well as wound infections and bioterrorism

  examples: bacillus and clostridium (-ve firmcutes)
• structure of a virus

  • NA genome surrounded by protein coat with or without a lipid envelope. the protein coat can be icoherd or helical. genomes can either be SS RNA/DNA or DS RNA/DNA
• lactic acid bacteria

  • they produce lactic acid as a fermentation end product.
  • phy lumen: firmicutes
  • example: S.mutants
• psychrotroph

  grows best at room temp but also grows at 5 degrees
• importance of outer membrane in gram -ve

  • lipopoy contains o-antigens that protects the host defence
  • they are also good for attachment
  • lipid A = exotoxin
• function of cell wall

  1. protection
  2. shape
  3. rigidity
• bacterial cell walls have

  1. peptidoglycan with NAG and NAM
  2. direct linkage of peptide chains
• why is penicillin not toxic to humans

  as penicillin stops production of peptidoglycan by preventing cross-linking

  therefore not toxic due to humans having no pep
• structures for movement

  • flagella
  • cilia
  • axial filament
  • gas vesciles
  • chemotaxis