Prokaryotes Flashcards
what is the internal organization of prokaryotes?
- small and simpler than eukaryotes
- Plasma Membran
- Ribosomes
- Cytoplasm
- circular Chromosome (in nucleoid region)
what is the job of the cell wall in prokaryotes?
- protect cell
- maintain shape
- prevent bursting
peptidoglycan
- carbohydrate polymer in cell wall
- characteristic of Domain Bacteria only
gram stain process
reveal type of cell wall in bacterial sample
- stain with crystal violet dye (purple) and Iodine
- rinse with alcohol
- stain with safranin dye (pink)
does Penicillin interfere with peptidoglycan synthesis or lipopolysaccaride
peptidoglycan (gram +)
what is the outer layer of gram - bacteria?
lipopolysaccaride
is gram + or - resistant to antibiotics?
negative (-)
is flagella an example of homologous or analogous structures?
analogous. similar functions, but arose independently. convergent evolution
binary fission
- 1 cell divides into 2 asexual
- very rapid in optimal conditions
do prokaryotes reproduce asexually or sexually?
asexually
mutations in prokaryotes
- short generations and large population (high genetic variation/ diversity = many alleles/gene)
- when alleles increase survival and reproduction (population changes)
what’s a negative consequence (for us) of rapid evolution in bacteria?
antibiotics become less and less effective, allows bacteria to become quickly resistant
how do sexual eukaryotes recombine and what happens as a result?
meiosis + fertilization
new allele combinations
what are the three recombination mechanisms and are they examples of horizontal or vertical gene transfer?
transformation, transduction, and conjugation
horizontal
transformation
prokaryotic cell take up foreign DNA from environment (Griffith’s experiment)
transduction
phages transfer prokaryotic genes from one cell to another
conjugation
direct transfer of genetic material from one cell to another, usually of same species
- involves F (fertility) factor - often a plasmid
- required for production of pilus: appendage for DNA transfer
- F+ cell
what are the two alternatives to prokaryotic metabolism?
- fermentation : make ATP without ETC
- anaerobic respiration : ATP with ETC using a different e- acceptor
facultative anaerobes
use o2 when present, fermentation or anaerobic respiration when absent
what drives prokaryotic systematic?
rRNA sequences
what are the two prokaryotic domains?
bacteria and archaea
is archaea more closely related to Bacteria or Eukarya?
Eukarya
proteobacteria
- large diverse, 5 groups
- endosymbiosis of alpha proteobacteria - > mtiochondria
cyanobacteria
- photoautotrophs - oxygenic photosynthesis
- endosymbiosis of cyanobacteria - > chloroplasts
extremophiles
- Archaea
- organisms that thrive in extreme conditions
- halophiles: high salt environments
- thermophiles/hypothermophiles: hot environments
- methanogens: release methane as byproduct of metabolism (obligate anaerobes and often in marshes and swamps)