Prokaryotes: Bacteria and Archaea Flashcards
prokaryote
is a type of cell
– “pro” means before
– “kary” means nucleus
what is true of prokaryotes?
any organism that lacks a distinct nucleus and other organelles due to the absence of internal membranes
-bacteria
-unicellular
-Consist of a single prokaryotic cell
-Are simple, single-celled organisms
-Include two domains: bacteria and archaea
-Can live in extreme environments and are found almost everywhere
What is the purpose of a cell wall?
Structural support (more rigid)
Additional filtering
prevent over-expansion
Capsule / slime layer
Outside of cell wall
* Adhere to surface
* Prevent dehydration
* Protect from sterilization
Endospore
Protected resting stage
* Copies chromosomes
* Many protective layers
* Removes water
* Shuts down metabolism
* Outer cell lyses
Endospore can survive
w/o nutrients
* UV radiation
* Desiccation
* Extreme heat
* Freezing
* Chemical disinfectant
Taxis
movement/ orientation toward or away
from a stimulus
Plasmids
Tiny rings of DNA
* 5-100 genes not required for survival
* Taken up from fragments of DNA from other species
* Plasmids have their own genes for replication
Genetic Recombination
alleles being brought
together in new combinations
Horizontal gene transfer
alleles transferred
between existing individuals
Example of obligate anaerobe
Domain ARCHAEA:
Methanogens
Strict anaerobes
* Important anaerobic decomposers
* Facilitate digestion
* Produce methane as a by-product
Ecological role
the major ways in which the
species interacts with other species and
affects its ecosystem
Archaeus fakus is an archaean. Which of the following is true about its cell structure?
It has a plasma membrane and DNA
Is S. madupicus unicellular or multicellular?
