Chapter 27: Bacteria & Archaea Flashcards
What are prokaryotes?
Organisms who’s cells lack a nucleus and other membrane-bound organelles
Prokaryotes are masters of ________ and _________.
adaptation, metabolism
What does it mean to be masters of adaptation?
An organism can thrive almost everywhere (Including places too acidic, salty, cold, hot etc.)
What does it mean to be masters of metabolism?
Organisms have numerous methods for obtaining carbon and energy
Prokaryote cells are _________ (smaller/bigger) than many eukaryote cells.
smaller
Define unicellular
Organisms that are made of only one cell (All functions are carried out within one cell)
Are prokaryotes unicellular or multicellular?
Unicellular
What are the 3 different morphologies of bacteria?
Coccus Bacillus Spirillum
What do coccus bacteria look like?
Sphere shaped
What do bacillus bacteria look like?
Rod shaped (Oblong oval cheeto thing)
What do spirillum bacteria look like?
Twists like a spiral (Zigzag thingy)
In eukaryotes with cell walls (plants), the walls are usually made up of cellulose or chitin. What do bacterial cell walls contain?
Peptidoglycan
What is peptidoglycan?
A polymer consisting of sugars and amino acids that form a mesh-like layer outside the plasma membrane of bacteria, forming a cell wall.
There are two types of cell walls, what are they?
Gram-positive (Gram +) Gram-negative (Gram -)
Describe a Gram-positive cell wall.
- Purple after staining
- Retains the crystal violet colour after staining
- Single layered, straight cell wall
- Rigid (less elastic)
- Large amount of peptidoglycan
- No outer membrane
- Not pathogenic to humans/animals

Describe a Gram-negative cell wall.
- Pink after staining
- Clear (does not retain the crystal violet colour) after staining
- Two layered, wavy cell wall
- Elastic (less rigid)
- Smaller amount of peptidoglycan
- Outer membrane present
- Pathogenic to humans/animals

Which picture is Gram-positive and Gram-negative?

A is Gram-positive
B is Gram-negative
Flagella affect ______.
motility
Some prokaryotes have specialized membranes that perform metabolic functions. What are the two prokaryotes?
- Aerobic Prokaryotes
- Photosynthetic Prokaryotes (cyanobacteria)
What specialized membrane do Aerobic Prokaryotes have?
Infolding of the plasma membrane
What specialized membrane do Photosynthetic Prokaryotes have?
Thylakoid membranes (similar to those in chloroplasts)
If you see a cell wall and it has peptidoglycan in the cell wall, it must be ________.
Bacteria
What is a capsule?
A sticky, dense layer of polysaccharide/protein that surrounds the cell wall of many prokaryotes.
What three factors give rise to high levels of genetic diversity in prokaryotes?
- Rapid reproduction
- Mutation
- Genetic recombination
What is rapid reproduction and mutation?
When populations reproduce with mutations (due to insertions, deletions and base-pair substitutions in DNA) at a rapid rate.
What is genetic recombination and what are the 3 steps?
- The combining of DNA from two sources
- Transformation
- Transduction
- Conjugation
In genetic recombination, what is transformation?
- A change in genotype and phenotype due to the cell’s take up of pieces of DNA from a leftover lysed cell

In genetic recombination, what is transduction?
- When bacteriophages (viruses that infect bacteria) carry bacterial genes from one host cell to another
- The recipient cell’s chromosome becomes a combo of DNA derived from two cells

In genetic recombination, what is conjugation?
- DNA is transferred between two prokaryotic cells that are temporarily joined.
- A pilus of the donor cell attaches to the recipient and retracts, pulling the two cells together, like a grappling hook.
- DNA is transferred
What is Prokaryote Metabolism?
The different methods of which prokaryotes use and aquire their carbon and energy
What are the 6 nutritional modes?
- Photoautotroph
- Chemoorganoautroph
- Chemoautotroph
- Photoheterotroph
- Chemoheterotroph
- Chemolithotroph
What are autotrophs?
Organisms that synthesize their own carbon source from an inorganic carbon source (photosynthesis/chemosynthesis).
What are heterotrophs?
Organisms that cannot synthesize their own carbon source and need to obtain it from the environment.
What are photoautotrophs?
Organisms that synthesize their own carbon source while obtaining energy (ATP) from a light source (phototrophs).
What are chemoorganoautotrophs?
Organisms that synthesize their own carbon source while obtaining energy (ATP) from organic (organotrophs) molecules (consisting of both C and H).
What are chemoautotrophs?
Organisms that synthesize their own carbon source while obtaining energy (ATP) from inorganic (lithotroph) molecules (missing either C or H).
What are photoheterotrophs?
Organisms that cannot synthesize their own carbon source and obtain energy (ATP) from a light source (phototrophs).
What are chemoheterotrophs?
Organisms that cannot synthesize their own carbon source and obtain energy (ATP) from organic (organotrophs) molecules (consisting of both C and H).
What are chemolithotrophs?
Organisms that cannot synthesize their own carbon source and obtain energy (ATP) from inorganic (lithotroph) molecules (missing either C or H).
Fill in the blanks


What are other prokaryote metabolic adaptations?
- Oxygen
- Nitrogen Metabolism
- Metabolic Cooperation
How does oxygen play a role in prokaryote metabolism?
There are prokaryotes that are:
- Obligate aerobes
- need an aerobic environment to survive - Obligate anaerobes
- need an anaerobic environment to survive - Facultative anaerobes
- prefer anaerobic conditions, but can survive in aerobic too
Why is nitrogen metabolism essential and how do prokaryotes do it?
- Essential for the production of amino acids and nucleic acids in all organisms
- Prokaryotes perform Nitrogen Fixation; converting atmospheric nitrogen (N2) to ammonia (NH3)
- When prokaryotes perform nitrogen fixation it also helps other plants (who cannot obtain nitrgoen from the atmosphere)
How does metabolic cooperation work?
Cells in a biofilm (surface-coating colonies) secrete signaling molecules that recruit nearby cells, causing the colonies to grow. This allows them to use environmental resources they could not use as individual cells.
What are cyanobacteria?
- Gram-negative photoautotrophs.
- Only prokaryotes with plantlike, oxygen-generating photosynthesis.
What is an extremophile?
An organism that grows in extreme conditions or habitats
What are the 6 types of extremophiles?
- Hyperthermophiles (Extreme thermophiles)
- Psychrophiles
- Acidophile
- Alkaliphile
- Halophile
- Barophile
What is a hyperthermophile?
An organism that thrives in extremely hot environments
- typically above 60 °C (140 °F)
- preferably 80°C
What is a psychrophile?
An organism that thrives in extremely cold environments
- roughly -20 °C to 10°C
What is an acidophile?
An organism that lives in an acidic environment
- at or below pH3
What is an alkaliphile?
An organism that lives in an alkaline (basic) environment
- at or above pH9
What is a halophile?
An organism that lives in a high salinity (salty) environment
- at least 2M of NaCl for growth
What is a barophile?
An organism that lives in a high pressure environment
True or False:
Only Archaea are extremophiles
False
Many Bacteria and Eukaryotes are also extremophiles
What are the main differences between Archaea and Bacteria?
