Bacteria Flashcards
Unicellular
organisms that have one cell only
Prokaryotes
Lack membrane bound nucleus and membrane bound organelles
Plasmid loops
Dna of bacteria
Location of bacteria
Everywhere in biosphere
2 heterotrophic nutrition
Saprophytic , bacteria of decay
Parasitic , streptococci (strep throat )
2 autotrophic nutrition
Photosynthetic , cyarobacteria
Chemosynthetic , nitrifying bacteria
Parts of monera cell
Genetic material ( dna cele replication )
Cytosol
Ribosome
Cell membrane
Slime capsule
Cell wall plasmids ( antibiotic resistance )
Flagellum
Beneficial bacteria
Make vitamins in the human gut
Make insulin and antibiotics
Harmful bacteria
Strep throat
Tooth decay
Precautions
Wipe surface with disinfectant wipe
Wear gloves
Asepsis
Free of pathogens
Sterility
Free of all microorganisms
Reproduction
Binary fission
Reproduction (procedure)
- Dna replicates
- Dna is connected to cell membrane
- Cell elongates , Dna move to opposite side
- When it’s doubles in size , divides, splits down middle and forms two equal sized identical cells
Antibiotics
Chemicals produced by microorganisms that stop the growth of, or kill other bacteria
How do bacteria become antibiotic resistant
One mutates and becomes antibiotic resistant
All other bacteria are killed by antibiotics except antibiotic resistant bacteria , create cell wall to resist and reproduce new populations of (arb)
(Arb) can transfer mutation to other bacteria
Overuse of antibiotics
Increases growth resistant bacteria
Factors affecting growth of bacteria
Temperature ; optimum is 20-30 degrees , some prefer 0-90
Oxygen concentration; aerobic , anaerobic, facultative anaerobes ,
ph , external solute concentration,
pressure
Survival in harsh and unfavourable conditions
Produce spores (From endospores )
Endospores
A dormant , tough , non - reproductive structure produced by bacteria
Endospore formation
Dna replicates moves to end of cell
Contents shrink due to loss of water
Forms a thick resistant wall formed in original cell producing endospore
Parent cell breaks down endospore remains dormant
Spores resist high temp
When conditions are favourable spores take in water and expand breaking their tough resistant wall
New bacterium divides by binary fission
Lag phase
Bacteria adapting to environment , getting prepared to reproduce
Log phase
Bacteria reproduce rapidly as there is ideal conditions
(Food , o2, space )
Stationary phase
Competition occurs due to shortage of food and o2 and is limited
Death phase
Numbers fall rapidly when death rate is more than rate of production
Survival
Small amount survive as dormant endospores
Dormant until ideal conditions
Batch culture processing
Fixed amount of sterile nutrient added to bioreactor
Undergoes all 5 stages of growth curve
Correct constant temperature
Nutrients consumed product formed
Bioreactor emptied re-sterilised and repeats process
Advantages of batch culture
If one batch is contaminated only one is destroyed
Bioreactor can be used for various processes
Continuos flow culture
Volume is constant
Microorganisms maintained at log phase
Nutrient continuously added to bioreactor
Culture medium with product is constantly taken away
Conditions are kept constant
Advantages ( Continuous flow)
Product forms quicker
no regular hutting down process
Less lag phases than in batch
