Topic 10: Prokaryotes Flashcards

• earths first organisms were most likely

  prokaryotes
• what two domains make up prokaryotes

  Bacteria and Archaea
• archaea and bacteria form distinct branches but inherited what

  simple prokaryotic cell organization from a common ancestor
• How big are prokaryotes?

  1-5um
• what limits size in prokaryotic cells

  diffusion
• what structural and functional adaptations contribute to prokaryotic success (5)

  1. cell-surface structures2. endospores3. motility4. internal organization and DNA5. reproduction
• what cell surface structures have contributed to prokaryotic success (4)

  -cell wall-peptidoglycan -capsule-fimbriae
• what does a cell wall in a prokaryote do

  • maintains cell shape
  • protects the cell
  • prevents from bursting in a hypotonic environment
• what kind of solution can cause a cell to burst

  hypotonic solution
• what is a hypotonic solution

  the solution has a lower solute concentration than the cell
• what is peptidoglycan


  a network of sugar polymers cross-linked by polypeptides
• what are archaea cell walls made of

  polysaccharides and proteins
• what organisms lack peptidoglycan

  eukaryotes and archaea
• What organism has peptidoglycan on their cell walls

  bacteria
• what are eukaryote cell walls made of

  cellulose (plants) or chitin (fungi)
• gram stain can be used to classify what organism


  bacteria
• What are gram positive bacteria?

  have simpler walls with a large amount of external facing peptidoglycan
• What are gram negative bacteria?

  have less peptidoglycan and an outer lipopolysaccharide membrane
• what is the purpose of the lipopolysaccharide outer membrane in gram negative bacteria

  can contain toxins and resist antibiotics
• what kind of bacteria is often more pathogenic

  gram-negative
• what is a capsule

  outer sticky polysaccharide or protein layer
• what are the functions of a capsule (3)

  • adhesion to each other and surfaces
  • protections from desiccation, phagocytosis, and viruses
  • evasion of a host's immune system
• what are fimbriae


  hairlike appendages that allow for attachment to substrates or each other
• what are pili

  Longer than fimbriae and allow for exchange of DNA
• what are endospores

  metabolically inactive version of the cell and can remain viable in harsh conditions for centuries-remain dormant until environmental conditions are suitable for growth
• how many prokaryotes are motile

  about half
• most motile prokaryotes use what

  flagella
• some prokaryotes with flagella can move how fast

  50 body lengths/ second
• how are flagella between eukaryotes, archaea and bacteria different

  made of different proteins and likely evolved independently
• in a heterogeneous environment, many prokaryotes exhibit what

  taxes
• prokaryotic cells usually lack what

  complex compartmentalization
• what do some prokaryotes have instead of organelles

  some have specialized membranes that perform metabolic functions -usually infoldings of the plasma membrane-e.g. thylakoid membranes in cyanobacteria
• what kind of genome do prokaryotes have

  have small genomes consisting of a single circular chromosome
• where is the chromosome in prokaryotes located

  in the nucleoid region since there is no nucleus
• what are plasmids

  Plasmids are small loops of extra DNA that aren't part of the chromosome. Plasmids contain genes for things like drug resistance and can be passed between bacteria.
• what have plasmids


  some bacteria species
• prokaryotes reproduce quickly by what

  binary fission
• how often do prokaryotes divide

  any where from 20 minutes to 24 hours
• binary fission rate depends on what

  enviornment
• rapid reproduction by binary fission is enabled by what

  -small cell size-short generation times-binary fission