Archaea + Bacteria Flashcards
List 5 characteristics of archaea
- Unicellular
- Prokaryotic
- Extremophiles (live in extreme conditions)
- Chemotrophs
- Binary fission reproduction
Similarities of archaea to bacteria
S: prokaryotes, use flagella for movement, similar genetic material structures (nucleoid, plasmid), same reproduction method
Differences of archaea to bacteria
Cell wall/membrane composed of different substances, ribosomes more similar to eukaryotes than bacterias
Define a halophile
- Living in high-salinity environments
- Photosynthesize using special proteins that give water a purple colour
- Can remove salt from inside itself to avoid “drying out”
Define a methanogen
- Makes methane through reactions between CO2 and H2
- (Mostly) strict anaerobe
- Found in ocean pockets, making methane from other small molecules
- Found in human/cattle gut (make methane from extra H2 produced by bacterias breaking down food)
Define a thermophile
- Found in hot environments (thermal vents in ocean, hot springs)
- Useful in biotechnical inventions
- Cultured and manipulated to make thermostable proteins (won’t break down at high temps)
Are archaea pathogenic (disease-causing) to humans?
No
Which groups of eubacteria (“true” bacteria) photosynthesize in ways similar to plants?
Cyanobacteria, proteobacteria
Describe nucleoids
Non-organized, central genetic material
Describe pilli and their function
Hair on organisms, used to carry cell copies from one organism to the other by attaching on to one another
Describe plasmids and their functions
Small loops of genetic materials containing few genes, copy themselves to create new organism cells. Contain useful genes helping them survive and remain in bacterial populations.
Describe peptidoglycan and its function
Bacteria layer forming the cell wall, covers cell membrane providing protection from any harmful outside sources
Describe the capsule and its function
Means to hold everything inside the cell together, protects against dehydration, high temps, antibiotics, and viruses (only found in some bacteria)
Describe the endospore and its function
Interior structure protecting genetic material from damage
Organic vs inorganic chemicals
Ochem: carbon containing chemicals
Inorg: non-carbon containing
Obligate vs facultative aerobes
Obligate: needing O2 for surivival
Facultative: Not always needing
Conjugation vs transformation
Conj: sexual reproduction
Transf: bacterial cell using DNA to live
How did horizontal gene transfer render E Coli dangerous?
A “bad” plasmid was absorbed, mutating the bacteria in a negative way
Why does an antibiotic bacteria killing another bacteria benefit it?
It takes over
How do bacteria develop resistance to antibiotics?
More they are used, more chance to develop resistance (Overusage and incompletion of rounds leaves certain bacteria alive to reproduce others with resistance, agriculture.. food and water)
Define symbiosis, examples
Interactions between two organisms where both benefit
1. Bacteria living in host for nutrients, provides protection to host
2. Bacteria living in the roots of legumes, providing nitrogen fixation
What are the 3 groups of bacteria based on nutritional requirements?
Aerobe, anaerobe, facultative aerobe
How do heterotrophic bacteria eat?
- Breaking down of complex compounds
- Fermentation
- Reproduction
How do autotrophic bacteria eat?
- Photosynthesis
- Chemoautotrophic (oxidation of elements)
What do sulfur bacteria use for metabolism?
H2S
How are bacteria important in recycling carbon and returning it to the atmosphere?
By decomposing the carbon, we avoid CO2 depletion, which would bring an end to photosynthesis and leave us without food,
What is bacteria’s role in the nitrogen cycle?
Nitrogen fixation, denitrification
Define nitrogen fixation
Converting N2 to NH3 (necessary for chlorophyll.. photosynthesis)
Define cyanobacteria
- Living in aquatic ecosystems
- Small, unicellular, colonial
- Photosynthetic
- Precursor to chloroplasts (organelles responsible for photosynthesis)
- Responsible for oxidation of Earth
- Known as “green-blue algae”
- Gram negative
What are 4 bacterial shapes?
Coccus (sphere)
Bacillus (rod-shaped)
Spirillia (spiral)
Vibrios (comma)
What are 3 ways bacteria attach?
Diplo-: pairs
Strepto-: chain
Staphylo-: clusters
Define proteobacteria
- Largest phylum of bacteria kingdom
- Includes pathogenic and nitrogen-fixing
- Ancestor to mitochondria
- Aka “purple bacteria”
- Some photosynthesize
- Gram negative
Define proteobacteria
- Largest phylum of bacteria kingdom
- Includes pathogenic and nitrogen-fixing
- Ancestor to mitochondria
- Aka “purple bacteria”
- Some photosynthesize
- Gram negative
Define gram-positivity
Cell will have a thick peptidoglycan layer (protection), will turn blue if dyed with specific violet dye. Many bacterial infections (pneumonia, UTI, strep)
Define binary fission
Bacterial way to reproduce asexually by duplication of DNA and splitting into two new daughter cells
Differences between binary fission and mitosis
- BF faster
- BF division occurs while DNA is being copied and not after
- No mitotic spindles are formed
- BF ONLY for reproduction, not for growth like mitosis
Define conjugation
Two prok. cells build bridge with pilli to share plasmid, allowing for genetic variability. Form of genetic recombination
How does conjugation occur?
- Shared plasmid “Fertility factor, F+ (donor)” containing genes to create pilus bridge and ability to replicate
- Bridge to F- (recipient). Protein relaxosome cuts plasmid open to share DNA through bridge. F+ NEVER ATTACHES TO F+ ONLY F-
- F+ copies missing strand, relaxosome glues DNA into a ball, plasmid receives a second strand and F- becomes F+
Define transformation
Bacterial cells pick up free floating plasmids
Define transduction
Virus infects bacterial cell by injection of (other) bacterial and viral DNA simultaneously
Horizontal vs vertical gene transfer
H: transfer of DNA between bacterial cells (conjugation, transformation, transduction)
V: passed down genes to offspring
What types of genes can plasmids contain that help them survive?
- Antibiotic resistance
- F+ to conjugate
- Help bacteria infect host
- Inactivate antibiotics/poisons
What is plasmid addiction?
Bacteria will die if plasmid is lost
Define the characteristics of E Coli
- Gram-negative
- Many strains, some causing bacterial infection
- Water/food contaminants
- Living in human/cattle gut
- Contamination due to undercooked food, unpasteurized beverage drinking, contact with feces
Define characteristics of Staphylococcus aureus
- Gram-positive
- Found on skin, hair, nose, throat
- Cause of several infections (minor: cut infections.. severe: sepsis, endocarditis, pneumonia, bone infection)
- Some are drug resistant (MRSA)
- Can cause food poisoning
