Monera Flashcards
General characteristics of Monera
- single-celled
- Prokaryotic
- Microscopic
- Carry out respiration
- Binary fission
- Have ribosomes
- Role: Decomposition of dead organisms
- Found everywhere
Name the shapes of Monera
- Coccus/Round
- eg: Streptococcus- causes septic throat - Rods
- eg: Coli- in the colon - Spirals
- eg: Cholera
What are the benefits of bacteria
- Production of yoghurt and cheese
- Manufacturing antibiotics
- Insulin production
- Nutrient recycling
Harmful effects of bacteria
- Can cause disease (Animal- food poisoning Plant- rot)
- Food spoilage (Milk turns sour)
- Tooth decay (Enamel)
Bacterial cell structure
Always present: - Cell wall - Cell membrane - Cytoplasm - Ribosome - Storage granule - Loop of DNA Sometimes present: - Capsule - Flagella - Plasmid
Role of Cell wall in Bacteria
- prevents cell from bursting
Role of Cell membrane in Bacteria
- Selectively permeable
Role of Cytoplasm in Bacteria
- Suspends ribosomes and storage granules
Role of Plasmid in Bacteria
- Cloning vector
- Bacterial resistance
Role of capsule
- Protects from drying out
Role of Flagellum
- Used for movement in search of food
How does Monera carry out sexual reproduction?
Binary fission
Briefly explain how binary fission occurs
- DNA replicates
- Cell elongates
- DNA copies move to opposite sides of the cell
- Ingrowth of membrane occurs
- Cytoplasm divides to form two daughter cells
- Bacteria produce themselves every 20 minutes
- leads to create clones (identical daughter cells)
Important consequences of bacterial reproduction
- Wounds become heavily infected very quickly
- Appear in large numbers
- Can transfer plasmids and antibiotic resistance
- Efficient returns of product in industry
Define Endospore
- unicellular resistant structure produced during harsh conditions
Steps in endospore formation
- DNA replicates
- Cytoplasm shrinks
- DNA is surrounded by a thick cell wall
- Outer cell breaks down
- Endospores remain dominant for decades
When conditions are suitable again
- Endospore absorbs water
- Spore wall softens and ruptures
- A new bacterial cell emerges, enlarges and reproduces by binary fission
What is meant by autotrophic?
Make their own food
Define Photosynthetic and give an example
Use light to make food
eg: Purple sulphur bacteria
Define Chemosynthetic
Use energy from chemical reactions
eg: Nitrifying bacteria
What is meant by Heterotrophic?
Take in food from other organisms
Define saprophytic and give an example
feed on dead organic matter
eg: bacteria of decay
Define parasitic and give an example
Feed on living host causing it harm
eg: streptococcus
Define Pathogen
Disease-causing agent
Define Antibiotic
Chemicals produced by micro-organisms to kill other micro-organisms
Role of antibiotics
Treat bacterial or fungal infections
What is meant by antibiotic resistance?
Bacterial or fungi are not killed by the antibiotic
How does antibiotic resistance develop
Misuse of antibiotics, using antibiotics to treat viral infections
How does resistance develop
- all bacteria are killed (good and bad)
- bacteria will have no competition
- Can increase in numbers rapidly
- Antibiotics will not affect it
- MRSA is a bacterial strain resistant to most antibiotics and is more common in hospitals
Abuse of antibiotics in medicine
- Using antibiotics to treat viral infections
- Patients failing to complete their full course of antibiotics
- Using a broad-spectrum antibiotic that inhibits many bacteria
Doctors are reluctant to prescribe antibiotics to patients with common cold-like symptoms. Suggest a biological reason for this statement.
- Common cold can be viral
- Antibiotics have no effect on viruses
Factors affecting growth
- Temperature
- Oxygen concentration (Anaerobic facultative can respire without oxygen) (Obligate anaerobes respire in absence of oxygen)
- pH
- External solute concentration
- Pressure
List the stages of the bacterial growth curve
- Lag
- Log
- Stationary
- Death/Decline
- Survival
Briefly describe the phases of the bacterial growth curve
- Lag phase: Bacteria numbers are low-Adapting to their new environment
- Log phase: Bacteria numbers increase rapidly- plenty of food, oxygen, moisture
- Stationary phase: Number remains high and constant- Reproduction rate=death rate
- Decline phase: Bacteria decrease in numbers (death rate is greater than reproduction rate)
- Survival phase: Bacteria survive as endospores
Define Bioprocessing
- Use of micro-organisms to produce food and other products
- Micro-organisms grow in a liquid medium in a bioreactor
Give a brief account of batch processing and give an example
Example: Antibiotics
Describe: Fixed amount of sterile nutrients are added to –the bioreactor at the start
-Go through all stages of growth
-Bioreactor is emptied and the product extracted at the end
Give advantages and disadvantages of batch processing
Advantages:
- Easier process to control
- Useful when products may be needed only in small amounts
- Some micro-organisms grow well for a short period of time
Disadvantages:
- Product not available at short notice
- Sterilising the bioreactor takes a lot of time
What is meant by Continuous flow processing? Briefly describe and give an example
Definition: Nutrients are continuously added to the bioreactor
Example: Single-celled protein
- Microorganism growth maintained at the upper log phase
- Products are continuously removed
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Give advantages and disadvantages of continuous flow food processing
Advantage: Quicker process
Disadvantage: Requires close monitoring
Give one example of a beneficial effect of bacteria, other than the production of antibiotics and one example of a harmful effect of bacteria
Beneficial effect: Nutrient recycling
Harmful effect: Cause disease
Name a method of asexual reproduction
Binary fission
Describe the process of asexual reproduction
- DNA replicates
- Cell elongates
- DNA copies and moves to opposite sides
- Ingrowth of membrane
- Cytoplasm divides to form two identical daughter cells
How do certain bacteria survive when environmental conditions become unfavourable?
Formation of endospore
Name 3 general shapes of bacterial cells
Rod, Cocci, Spiral
What is the difference between asepsis and sterility
Asepsis: Free of pathogens
Sterility: Free of micro-organisms
Give one way in which bacteria cope with unfavourable environments
Endospores
Distinguish between Batch processing and Continous flow
Batch processing: a fixed amount of nutritions added at the beginning
Continuous flow: Nutrients continuously fed into the bioreactor
Explain what is happening at the stationary phase
Stationary phase: Bacteria Number remains high and constant
- Reproduction rate=death rate
- Limited space and food
Other than being prokaryotic state two ways in which a typical bacterial cell differs from a typical human cell
- Cell wall
- Size
Misuse of antibiotics
- survival of resistant strains
Name two forms of heterotrophic nutrition
- Parasitic
2. Saprophytic
