Ch21 Monera Flashcards
State some features of bacteria
Unicellular
Prokaryotic
Classified according to their shapes
What are the shapes of bacteria? Give examples.
Spherical - pneumonia, streptococcus
Rod - E-Coli, TB
Spiral - syphilis, cholera
Draw a typical bacteria cell OR name its parts
Cell membrane
Storage granules
DNA (chromosome)
Cytoplasm
Ribosome
(Capsule)
(Flagella)
(Plasmid)
What are the functions of the parts of the bacteria cell?
Cell wall: Shape and structure
Cytoplasm: Contains ribosome and storage granules
Nuclear material (DNA): Single chromosome
Capsule: protection
Flagella: Movement
Plasmid: Contains genes for drug resistance
How do bacteria reproduce?
Binary fission
Describe the process by which bacteria reproduce.
- Chromosome attaches to plasma membrane
- DNA fully replicates
- Cell elongates, chromosomes separate
(-Cell wall grows)
- Cell divides into 2 daughter cells
DEFINE endospore
Produces a tough wall around chromosome which can withstand unfavourable conditions, allowing bacteria to survive for 100s of years.
Contents of bacterium are discarded except genetic material
How do bacteria obtain nutrition? (4 types)
HETERO
Photosynthetic: use light as energy source. Eg, Purple Sulfur Bacteria
Chemosynthetic: Use chemical reactions. Eg, nitrifiying bacteria
AUTO
Parasitic: live hosts
Eg, streptococcus
Saprophytic: dead hosts
Eg, bacteria of decay
What are the factors affecting bacterial growth?
Temperature: prefer 25°-30°, high temperature = denatured, low temperature= slower growth
pH: prefer 7, too high or low = denatured
Oxygen: Aerobic bacteria require oxygen. This is why O2 is bubbled through bioreactors.
External solute conc.: Bacteria gain/lose water by osmosis, jam making uses this principle
Pressure: inhibited by high pressure, pressure tolerant bacteria used in bioreactors
DEFINE antibiotics
Chemicals made by bacteria or fungi that inhibit the growth of or kill bacteria. DO NOT KILL VIRUSES.
How do bacteria develop antibiotic resistance?
Due to misuse of antibiotics - not finishing a course = allowing some bacteria to survive and pass on resistance
Name a multi-resistant bacteria.
MRSA
Describe the stages of bacterial growth.
LAG: no change in numbers, adjusting to environment
LOG: exponential growth, rapid binary fission
STATIONARY: birth rate = death rate
DECLINE: population falls due to unfavourable conditions, too much competition for resources
SURVIVAL: some bacteria form endospores
DEFINE fermentation
Growth of organisms in a liquid medium, takes place in bioreactor
Differentiate between batch and continous flow culture.
BATCH: Fixed amount of nutrient added at start,
organisms go through first 3 stages,
product formed for a short time then cycle starts again
CONTINOUS FLOW: nutrients added continously, organisms maintained in Log phase,
product formed all the time for long periods
