Biodiversity - Prokaryotes (Bacteria) Flashcards
Archaea similarities to eukaryotes
DNA and synthesis
Archaea unique traits
can survive in harsh environments
Bacteria traits
circular DNA without nuclear membrane, no membrane-bound organelles, 1/10th the size of a eukaryotic cell, has a flagella that helps it move, reproduces using binary fission
Pili
hair like structures usually found in gram neg bacteria that helps it stick to surfaces and forms conjugation bridge
Chromosome
single loop of DNA that is folded on itself. Controls cell’s function
Nucleoid
region of cytoplasm where DNA is found
plasmid
accessory loop of DNA, contains few genes, can be responsible for: conjugation, antibiotic resistance, unique metabolic properties: ability to break down hydrocarbons (bio remediation)
Capsule
outside the bacteria, stores nutrients and protects from changing environmental conditions
cell wall structure
peptidoglycan which is a combination of protein and polysaccharides
Gram-negative bacteria
have additional layer of membrane that contains lipopolysaccharide. extra layer inhabits the uptake of antibiotics - protecting the bacteria, appear pink and don’t absorb stain
Gram-positive bacteria
don’t have the extra membrane, appear purple, and absorb stain
4 Bacteria classification
their shape, nutrition, respiration, and their reaction to being stained
Bacterial shapes
cocci (spherical), bacilli (rod-shaped), spirilli (spiral)
Live as single cells
mono
live in pairs
diplo
live in linear chains
strepto
live in clusters
staphylo
metabolic diversity
bacteria can produce energy in a variety of circumstances
Autotroph
produces its own food by either photosynthesis or chemosynthesis (energy from chemicals)
Heterotroph
organism that obtains energy from the foods it consumes, can either be decomposers or parasites
obligate aerobes
require oxygen for cellular respiration
obligate anaerobes
cannot live in the presence of oxygen
facultative anaerobes
can live with or without oxygen
Bacteria reproduction
very fast, every 15-20 mins, depends on space food and temp, growing colony can poison itself form metabolic waste accumulation, high mutation rate
binary fission
asexual, like mitosis but for reproduction, genetically identical to parent, happens every 20 mins in good conditions
Conjugation in bacteria
one cell passes a copy of its plasmid to another
conjugation bridge
The specialized pilus that forms a passageway for the transfer of genetic information.
Conjugation process
- special pilus forms connection between two bacterial cells
- dorner cell copies its plasmid and passes copy through the bridge
- cell speartes. recipient bacteria has new alleles it can incorporate into its genome by crossing over
Bacterial Survival
under very unfavourable conditions some bacteria form endospores.
endospore formation
original cell replicates its DNA that then becomes surrounded by a durable wall
2 ways bacterial cells exchange genetic info
- transduction
- transformation
transduction
viruses carry bacterial DNA form one bacterium to another
transformation
Bacteria take DNA right from environment that came from a dead bacteria which released its DNA into the environment
Transduction in bacteria
- virus infects bacteria
- during assembly virus packages some of host DNA
- new virus infects another bacterial cells, the host DNA is transferred between bacterial hosts
nitrogen fixing bacteria
contain enzymes that allow them to convert (or fix) nitrogen from the air into a useable form
Chemosynthetic bacteria
convert hydrogen sulfide (H2S) gas into energy
cyanobacteria
photosynthetic bacteria that convert CO2 and water into sugar (C6H12O6)
Pathogens
organisms that cause disease, small portion of bacteria, most bacteria diseases are caused by toxins released by the bacteria
result of bacteria toxins
- poison cells and damage tissue 2. interfere with cell signalling
- over-stimulate cells causing them to malfunction
Bioflims
some bacteria form it
is a matrix of polysaccharide
once formed traps other bacteria
protects the bacteria so it is harder to kill
Antibiotics
chemicals that either kill bacteria or prevent their growth and reproduction
Who discovered penicillin?
Alexander Fleming in 1928
what do antibiotics affect
bacteria but no eukaryotic cells
what ways can antibiotics attack bacteria
- cell walls and cell membrane can be damaged or prevented from forming
- prevent protein synthesis
- interfere with DNA replication
- block bacterial metabolism
misuse of antibiotics
use antibiotics until they feel better but stop before all bacteria is destroyed. killing the most susceptible bacteria but leaving the more resistant bacteria allowing bacteria to become resistant
