Prokaryotes: Bacteria & Archaea Flashcards
Prokaryotes thrive almost everywhere:
- ——: can live in very high salinities
- ——: can survive 3 million rads of radiation (3,000 x human fatal dose)
- ——: can live at temperatures as high as 80° C (176° F)
- ——: can grow at pH 0.03 (acidic enough to dissolve metal)
- Halobacterium Species
- Deinococcus Radiodurans
- Thermus Aquaticus
- Picrophilus Oshimae:
Prokaryotes are most —, and likely the —, orgnaisms on earth
- Abundant
2. First
Prokaryotes are divided into what 2 domains?
- Bacteria
2. Archaea
We actually have more — cells than our — cells
- Bacterial
2. Own
Because bacteria are so much smaller, only comprise about —% of our body weight
0.3%
Common features among all cells:
- ——
- —
- ————
- —
- Plasma Membrane
- Cytoplasm
- Double-stranded DNA Genome
- Ribosomes
Cell Wall:
- — have peptidoglycan
- — lack peptidoglycan
- Bacteria
2. Archaea
DNA replication:
- Both have single origin of —
- Archaeal DNA replication is more similar to that of —
- Replication
2. Eukaryotes
Gene Expression:
*Archaeal — and — are more similar to those of eukaryotes
- Transcription
2. Translation
Autotrophs – carbon from inorganic CO2
- —: energy from Sun
- —: energy from oxidizing inorganic substances (e.g., H2S, NH3 or Fe2+)
- Photoautotrophs
2. Chemolithoautotrophs
Heterotrophs – from organic molecules:
*—: light as energy source but obtain organic carbon made by other organisms
*—: both carbon atoms and energy from organic molecules
Humans are another example
- Photohetrotrophs
2. Chemoheterotroph
Prokaryotic metabolism varies with respect to O2:
- ——: require O2 for cellular respiration
- ——: poisoned by O2 and use anaerobic respiration/fermentation
*——: use O2 if present, but also carry out anaerobic respiration/fermentation if not
- Obligate Aerobes
- Obligate Anaerobes
- Facultative Anaerobes
Most prokaryotes are:
- —, although some species form colonies
- 0.5–5 µm, much — than eukaryotic cells (10–100 µm
- Unicellular
2. Smaller
Prokaryotic cells have a variety of shapes; 3 most common are:
- —
- —
*—
- Spheres (cocci)
- Rods (bacilli)
- Spirals
An important feature of nearly all prokaryotic cells is their cell wall:
- Maintains ——
- — the cell
- Prevents — in a hypotonic environment
- Cell Shape
- Protects
- Bursting
Eukaryotes (plants and fungi): made of — or —
- Cellulose
2. Chitin
Prokaryotes:
- Bacteria: contain —, a network of sugar polymers cross-linked by polypeptides
- Archaea: contain — & — but lack peptidoglycan
- Peptidoglycan
2. Polysaccharides & Proteins
Used to classify bacteria by cell wall composition
- ———: have less peptidoglycan and an outer membrane that can have toxic lipopolysaccharides
- ———: have simpler cell walls with a large amount of peptidoglycan
- Gram-negative bacteria
2. Gram-positive bacteria
Gram-negative bacteria:
- —— of — in cell walls are toxic, causing fever or shock
- Tend to be more —— because outer membrane impedes drug entry
- Lipid portions of lipolysaccharides (LPS)
2. Antibiotic resistant
Gram-positive bacteria:
- Some are — and — to one or more antibiotics
- Many antibiotics (e.g., penicillin) target — and damage bacterial ——
- Virulent & Resistant
2. Cell walls
Capsule: —— or —— that covers some prokaryotes
*Allows adherence to the —, or other individuals, and can shield pathogenic bacteria from the host immune system
- Sticky polysaccharide
- Protein layer
- Substrate
—: extensions of some prokaryotes that help them stick to their substrate or other individuals in a colony
Fimbriae
—: longer than fimbriae and allow prokaryotes to exchange DNA
Pili
Most motile bacteria propel themselves by —
- Scattered about the surface or concentrated at one or both ends
- — of bacteria, archaea, and eukaryotes perform similar functions, but are composed of different proteins and likely evolved independently
- Flagella
2. Flagella
~Half of all prokaryotes exhibit —: the ability to move toward or away from a stimulus
*E.g., — is the movement toward or away from a chemical stimulus
- Taxis
2. Chemotaxis
Internal structure is simpler than in eukaryotes
*Prokaryotic cells usually lack ——
Complex compartmentalization (organelles)
Some prokaryotes do have specialized membranes that perform ——
* There are usually — of the plasma membrane
- Metabolic functions
2. Infoldings
Physical arrangement of DNA is also simpler:
- Prokaryotes lack a —; chromosome is located in the — region with no surrounding membrane
- Prokaryotic genome has — DNA than the eukaryotic genome
- Most of the genome consists of a —chromosome
- Typical prokaryotes also have smaller rings of independently replicating DNA called —
- Nucleus
- Nucleoid
- Less
- Circular
- Plasmids
Key features of prokaryotic reproduction:
*—
*Reproduce by ——
*Have — generation times
~Can divide every — hours under optimal conditions
~As a result, populations can reach trillions of individuals
- Small
- Binary fission
- Short
- 1-3
Short generation time allows prokaryotes to evolve —
Quickly
Prokaryotes are not “—“ but are highly —
- Primitive
2. Evolved
Prokaryotes have considerable ——
Genetic variation
3 factors contribute to this genetic diversity is prokaryotes:
- ——
- —
- ——
- Rapid Reproduction
- Mutation
- Genetic Recombination
Mutation rates during binary fission are —, but because of rapid reproduction, mutations can accumulate — in a population
- Low
2. Rapidly
— diversity from mutations allows for — evolution
- High
2. Rapid
Genetic recombination is the combining of — from — sources
- DNA
2. Two
Prokaryotic DNA from different individuals can be brought together by:
- —
- —
- —
- Transformation
- Transduction
- Conjugation
—: taking up and incorporation of foreign DNA from the surrounding environment
*E.g., nonpathogenic Streptococcus pneumoniae can be transformed to pneumonia-causing strain if exposed to DNA from pathogenic strain
Transformation
—: movement of prokaryotic genes between bacteria by bacteriophages
*Usually results from accidents that occur during the phage replicative cycle
Transduction
—: process where genetic material is transferred between prokaryotic cells
Conjugation
In bacteria, the DNA transfer is always ——
One way
A donor cell attaches to a recipient by a pilus, pulls it closer, and transfers DNA through “——”
Mating Bridge
A piece of DNA called the —— is required for the production of pili
F Factor (F for fertility)
F Factor can exist either as a:
- —
- Segment of — within the bacterial —
- Plasmid
- DNA
- Chromosome
Cells containing the F factor as a plasmid (F+) function as — donors during —
- DNA
2. Conjugation
Cells without the F factor (F-) function as —— during conjugation
DNA Recipients
An F+ cell converts an F- cell to F+ if a copy of the entire F plasmid is —
Transferred
A cell with the F factor built into its chromosomes also functions as a donor during conjugation
*Called an ——
Her Cell (for High Frequency of Recombination)
F- cells also function as DNA recipients during — with ——
- Conjugation
2. Hfr Cells
The recipient becomes a — F- bacterium, with genomic DNA from two different cells
*—— become an F+ or Hfr cell! No F factor is retained.
- Recombinant
2. Does NOT
——: carry genes for antibiotic resistance
R Plasmids
Antibiotics kill antibiotic-sensitive bacteria, but not — with specific —— that counter the antibiotic
- Bacteria
2. R Plasmids
Through ——, the fraction of bacteria with genes for resistance — in a population exposed to antibiotics
*Antibiotic-resistant strains of bacteria are becoming — common
- Natural Selection
- Increases
3, More
Some prokaryotes are ——, but many others have — interactions with humans
- Human Pathogens
2. Positive
Human intestines are home to about —— species of bacteria
500-1,000
Many of the species of bacteria in humans are — and break down food that is undigested by our intestines
Mutualists
— cause about half of all human diseases
* E.g. Lyme disease is caused by a — and carried by ticks
- Bacteria
2. bacterium
Pathogenic prokaryotes typically cause disease by releasing:
- —: secreted and cause disease even if the prokaryotes that produce them are not present
- —: released only when bacteria die and their cell walls break dow
- Exotoxins
2. Endotoxins
Prokaryotes are the principal agents in —, the use of organisms to remove pollutants from the environment
Bioremediation
Bacteria can be engineered to produce —,—,— & ——
- Vitamins
- Antibiotics
- Hormones
- Natural Plastics
Bacteria are also being engineered to produce — from waste biomass
Ethanol
