Topic 7 - Prokaryotes Flashcards
What is a prokaryote?
a small unicellular organism that lacks membrane-enclosed organelles, meaning no nucleus, but they do have cell walls
What makes prokaryotes so adaptable?
- small size
- binary fission
- short generation time
What makes up the cell wall?
peptidoglycogen
- NOT cellulose
- it provides: cell shape, protection, and prevention from exploding
What is binary fission?
a form of asexual reproduction where one cell is splitting into two daughter cells
How does bacteria exchange genetic info?
- horizontal gene transfer
- transformation
- transduction
- conjugation
What are chemoautotrophs?
produce energy directly from chemicals in the environment, carbon comes from CO2
ex) many prokaryotes
What are photoautotrophs?
use light energy (directly from sun aka photosynthesis) & CO2 , primary producers that support the food web
ex) cyanobacteria
What are chemoheterotrophs?
gets energy by consuming other organisms, carbon comes from compounds
ex) animals, fungi
What are photoheterotrophs?
use light energy (directly from sun aka photosynthesis) cannot use CO2 as their sole carbon source (comes from organic molecules), this case is rare
ex) a few prokaryotes
Define extremophiles
many in the archaea domain, live in extreme environments
Define halophiles
live in very salty habitats, can be any ionic crystalline compound not just NaCl
Define methanogens
live in oxygen-free habitats, produce methane as a waste product
ex) swamp substances, cow & termite guts
Define thermophiles
live in very hot habitats
- many are chemoautotrophs
- some used for PCR techniques
What are gram positive bacteria?
- have peptidoglycan wall
- can trap purple stain
What are gram negative bacteria?
- have lipopolysaccharide layer outside of the cell wall
- DO NOT absorb stain readily
