Bacteria (Monera) Flashcards
What is the function of ribosomes in bacterial cells?
They are the site of protein synthesis
Describe the bacterial cell wall.
Main function- to prevent osmotic bursting of the cell
Cell wall is permeable to water, solutes and small insoluble particles
Rigid extracellular structure (no cellulose)
What is the function of the slime layer/capsule?
Provides protection.
Do bacteria have membrane enclosed organelles?
No.
The ribosomes, bacterial chromosome and plasmid are suspended.
What is a flagellum?
-Allows movement in search of food or more suitable growing conditions.
Is the flagellum present in all bacteria?
No.
What is a plasmid?
- Small circle of DNA
- Carries genes of benefit to the bacterium eg. resistance to antibiotics
What is the function of the mesosome?
- Infolding of cell membrane
- Involved in aerobic respiration
What is the function of the storage granules?
To store food or waste.
What factors affect the growth of bacteria?
- Temperature
- Oxygen concentration
What do aerobic bacteria need for respiration?
-Need oxygen
Do anaerobic bacteria need oxygen to respire?
No, they do not need oxygen.
What can facultative anaerobes do?
-Can respire with or without oxygen
What can obligate anaerobes not do?
They cannot not use oxygen and do not grow if oxygen is present.
Does high pressure stop bacterial growth?
Yes, however some bacteria can withstand high pressure.
How are endospores formed?
These are formed when the bacterial chromosome replicates.
What happens to the endospore when there is favourable conditions?
-The spores absorb water, break their walls and reproduce by binary fission.
Name two economic benefits of bacteria.
- Produce antibiotics
- Produce yogurt and cheese
Name two harmful economic effects of bacteria.
- Causes food poisoning
- Causes cholera
What are antibiotics?
-Are chemicals produced by micro-organisms that stop the growth of, or kill other micro-organisms without damaging human tissue.
How do bacteria develop a resistance to antibiotics?
They mutate
Can antibiotics be abused?
- Yes
- Repeated exposure to antibiotics enables resistant strains of bacteria to evolve.
What can cause bacteria to become resistant?
Not taking the full course of antibiotics once prescribed can also cause resistant bacteria to develop.
What are pathogenic bacteria?
Are bacteria that cause disease
What kingdom do bacteria belong to?
Kingdom Monera
Are bacteria eukarotic or prokaryotic?
They are prokaryotic
Describe the lag phase.
- Adapting to new environment
- Numbers remain constant
- Bacteria are producing the enzymes necessary to digest the nutrients
- The rate of growth begins to increase towards the end of this phase
Describe the log phase.
- Numbers increase rapidly
- Ideal conditions, plenty of food, moisture, space and oxygen
Describe the stationary phase.
- No increase in bacterial numbers
- New bacteria = number of dying bacteria
- Lack of food, space, moisture
- Build up of toxins
Describe the decline phase.
- Death phase
- Rapid decline in bacterial numbers
Describe the survival phase.
-Small number of bacteria survive by remaining dormant as endospores.
What is a bioreactor?
Is a vessel in which biological reactions take place
What are the two main methods of food processing?
- Batch food processing
- Continuous flow food processing
Describe batch food processing.
-A fixed amount of sterile nutrient is added to the micro-organisms in the bioreactor.
What happens at the end of the batch food processing.
-At the end of production the bioreactor is cleared out. The product is separated from the rest of the solution and is purified.
What happens in continuous flow food processing?
-Nutrients are continuously fed into the bioreactor
What phase in the growth curve is continuous flow food processing kept at?
Log phase
What does unicellular mean?
They are made up of only one cell.
What are three main types of bacteria?
- Rods
- Round (coccus)
- Spiral
Give an example of a rod shaped bacteria.
E.coli
Give an example of a round shaped bacteria.
Streptococcus
Give an example of a spiral shaped bacteria.
Syphilis
How do bacteria reproduce?
Produce by binary fission
How do bacteria asexually reproduce?
- DNA stand replicates
- How there is 2 strands of DNA
- The bacterial cell elongates. A strand of DNA moves to each end of the cell
- The cell splits and two identical cells are formed.
When are endospores formed?
Formed when conditions become unfavourable.
How long does an endospore take to form?
About 8 hours
Describe the formation of the endospore.
- Bacterial chromosome replicates
- One of the strands of DNA becomes enclosed by a tough walled endospore formed within the bacterial cell.
- Parent cell breaks down.
- Endospore remains dormant
Where are chemosynthetic involved in?
-Parts of the nitrogen cycle
