Prokaryotes Flashcards
Prokaryote
A single-celled organism with no nuclei and membrane-bound organelles
Two domains of prokaryotes
Archaea and Bacteria
Nucleoids
The area where DNA is found within prokaryotes
Photoheterotrophs
C
Do archaea and eukaryotes form a monophyletic group?
yes
Do bacteria and archaea form a monophyletic group?
NO
The oldest fossil was dated to about
3.8 billion years ago in the early Archaean Eon
Photosynthesis by cyanobacteria is dated t o about
2.6 billion years ago in the Late Archaean Eon
Evidence for Photosynthesis?
Banded Iron formations
HaloBacterium
Archaea that are very salt tolerate
Deinoccous radiodurans
Bacteria that can survive 300 million rads of radiation (3,000 times more than a human can handle)
Picophillus Oshimae
Can grow in Ph of .03 which is acidic enough to dissolve metal
Thiomargarita Namibiensis
A bacterium bigger than a poppy seed
Plasmolyze
Cell shrivels up and shrinks away from their cell wall in a hypertonic environment
Difference between Bacteria and Archaea Cell walls?
Bacteria use peptidoglycan within the cell walls while archaea use different polymers
Peptidoglycan
A fabric of modified sugars cross-linked by polypeptides. Helps anchor things off cell wall
Gram Stain
A process discovered by Hans Christain Gram in determining the structure of bacterial walls
Gram Stain Process
- Sample are stained with crystal violet dye and iodine
- Rinsed in alcohol
- Rinsed in red dye, like safranin
Gram-Positive Bacteria
Bacteria that have simple cell walls mainly composed of a thick layer of peptidoglycan
Gram-Negative Bacteria
More complex walls that contain less peptidoglycan. Outer walls have lipopolysaccharide
why does Penicillian work better on gram-positive bacteria
Penicillin interferes with the cross-linkages of peptidoglycan, and since the main component of their basic walls is peptidoglycan, their wall is heavily damaged and the bacteria loses its structure
Capsule
An outer wall that provides more protection to a bacterium and its cell wall
Streptococcus Bacterium
Bacteria with a capsule that allows them to attach to respiratory-tract cells
Endospores
Dormant cells produced b a cell in an environment with little water to nutrients and are incredibly resistant to harsh conditions
