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Viruses and Bacteria - Coggle Diagram

- - - - a protein tail piece attaches the phage to the host & injects the phage DNA inside
- - - - extreme thermophiles: have adaptations that make their DNA & proteins stable at high temperatures
- - - - viral infections cannot be treated by antibiotics
- - - - virus makes use of host enzymes, ribosomes, tRNAs, amino acids, ATP, and other molecules
  - - - short duration
        
        results in death of host cell
        
        virulent (only reproduce via the lytic cycle)
    - - long duration
        
        replication of the virus w/o destroying host cell
        
        temperate: utilizes both lysogenic + lytic cycles to replicate
  - - - Retroviruses are almost always lethal
      - HIV is the retrovirus that causes AIDS
    - - unlike a prophage, a provirus remains a permanent resident of the host cell
- - - - autotrophs require CO2 or related compounds as a carbon source
        
        heterotrophs require an organic nutrient to make other organic compounds
  - - - facultative anaerobes can use O2 if it is present or carry out fermentation or anaerobic respiration if not
- - - - Most prokaryotes lose water & experience plasmolysis in hypertonic environments
      - Eukaryote cell walls are made of cellulose of chitin
        
        Peptidoglycan: a network of sugar polymers cross-linked by polypeptides
        
        Archaeal walls contain a variety of polysaccharides & proteins but lack peptidoglycan
    - - Gram-positive bacteria have simpler walls w/large amount of peptidoglycan
        
        many antibiotics target peptidoglycan & damage gram-positive bacterial cell walls
      - Gram-negative bacteria have less peptidoglycan & are more complex w/outer membrane that contains lipopolysaccharides
        
        gram-negative bacteria tend to be more resistant to antibiotices than gram-positive
    - - Capsule if it is dense & well-defined, or a slime layer if it is not well organized
      - some bacteria from metabolically inactive endospores when water or nutrients are lacking
      - fimbriae: hairlike appendages that allows them to stick to their substrate other individuals in a colony
        
        pili (sex pili): are longer than fimbriae & function to pull cells together enabling the exchange of DNA
        
        Taxis: the ability to move toward or away from a stimulus
        
        Prokaryotes have one circular chromosome; eukaryotes have multiple linear chromosome
        
        Prokaryotes lack a nucleus; the chromosome is in the nucleoid a region with no membrane
        
        Plasmids: smaller rings of independently replicating DNA
    - - prokaryotes reproduce quickly by binary fission & can divide every 1-3 hours under optimal conditions
        
        3 key features: small, reproduce by binary fission, & have short generation times
  - - - Mutation rates are typically low, but mutations accumulate rapidly with short generation times & large populations
    - - transduction: phages carry prokaryotic genes from one host cell to another
        
        conjugation: the process through which DNA is transferred between 2 prokaryotic cells
        
        F factor: piece of DNA; required for the production of pili
        
        cells that have the F factor in their chromosome function as donors during conjugation
        
        Hfr cells, high frequency of recombination
        
        homologous segments of the chromosomal DNA from the Hfr cell recombines with that of the F- cell
        
        antibiotics kill most bacteria, but not those with R plasmids, plasmids that carry resistance genes
        
        R plasmids also have genes that encode the pili used to transfer DNA between cells, enabling the rapid spread of resistance
        
        F plasmid: function as DNA donors