30 Questions
What type of metabolism includes major metabolic pathways such as energy production, release, cell component synthesis, and enzyme production?
Primary metabolism
Which type of culture system is limited by nutrient availability, atmosphere diffusion at the liquid surface, and is not suitable for industrial-scale production?
Batch culture
In what growth mode does the culture fill until the vessel is full, allowing for controlled growth and optimization?
Fed batch
Which type of viral replication relies on the subversion of the host replication machinery and leads to cell destruction?
Lytic replication
What is the process where some bacteriophages can integrate their genome into the host and replicate alongside the host until favorable conditions trigger lytic replication?
Lysogenic replication
What causes bacterial evolution by permanently altering a single cell without necessarily causing immediately noticeable changes?
Mutation
What is the primary function of iron in a bacterial cell?
Cytochrome component, enzymatic cofactor
Which element makes up the main inorganic cations and acts as an enzymatic cofactor in bacterial cells?
Potassium
In bacterial metabolism, which type of organisms obtain carbon from CO2 as the sole or primary source?
Lithotrophs
What is the function of phosphorus in a bacterial cell?
Nucleic acids, nucleotides, phospholipids
Which energy source do chemotrophs utilize in bacterial metabolism?
Reduced inorganic compounds
What is the significance of secondary metabolism in microbial organisms?
Survival under adverse conditions and production of antibiotics
What is the main method of reproduction for most bacteria?
Binary fission
Which bacterium has a significantly longer generation time compared to Escherichia coli?
Mycobacterium leprae
During which bacterial growth phase does growth and division occur at the maximum possible rate?
Exponential (log) phase
What happens to viable cell numbers during the death phase of bacterial growth?
They decrease at an exponential rate
Which bacterial growth phase is characterized by no immediate increase in cell number and old cells needing time for synthesis of new components?
Lag phase
What type of changes occur during the stationary phase of bacterial growth?
Morphological and metabolic changes
What is the primary purpose of targeted mutagenesis in the context of increasing production in organisms?
To specifically add or remove genes to improve overall yield
How did scientists increase the production of Penicillium chrysogenum by a factor of 20?
By using UV mutagenesis in combination with spontaneous mutagenesis
What role did E.coli play in the production of the first human-identical insulin (humulin) in 1978?
Served as a host for the cloned human insulin gene
In the context of bacterial growth, what is the significance of understanding different stages of bacterial and viral replication?
To develop strategies for controlling bacterial infections
Why is the link between evolution and antibiotic resistance particularly important in the context of microbial metabolism?
To combat the development of antibiotic-resistant bacteria
Which method was used to produce Humulin and similar products, marking over 25 years of their usage?
Cloning human insulin gene into E.coli
What is the process by which bacteria can evolve through the direct uptake of DNA through the cell membrane?
Transformation
Which of the following is NOT one of the three main mechanisms by which bacteria can evolve?
Replication
What is the main reason antibiotic usage can act as a selective pressure on bacteria?
Removes competition for resistant cells by killing susceptible cells
How does initial strain improvement aim to boost efficiency of production?
By producing products at low concentrations
Which type of mutation is usually random and infrequent, and can make things worse during bacterial evolution?
Spontaneous mutation
In bacterial evolution, what is the mechanism that involves the transfer of genetic material between two directly connected bacteria?
Conjugation
Study Notes
Microbial Growth and Evolution
Top 10 Elements Making Up a Bacterium
- Carbon (50%): main constituent of cell, cell material, and water
- Oxygen (20%): electron acceptor in aerobic respiration
- Nitrogen (14%): amino acids, nucleotides, and coenzymes
- Hydrogen (8%): cell water and organic compounds
- Phosphorus (3%): nucleic acids, nucleotides, and phospholipids
- Sulfur (1%): inorganic sulfates, hydrogen sulfide, and organic sulfur compounds
- Potassium (1%): main inorganic cations and enzymatic cofactor
- Magnesium (0.5%): inorganic cations and enzymatic cofactor
- Calcium (0.5%): inorganic cations and enzymatic cofactor
- Iron (0.2%): cytochrome component and enzymatic cofactor
Sources of Carbon, Energy, and Electrons
- Carbon source: autotrophs (CO2) or heterotrophs (organic compounds)
- Energy sources: phototrophs (light), chemotrophs (chemical compounds)
- Electron sources: lithotrophs (inorganic compounds), organotrophs (organic compounds)
Bacterial Cell Division
- Each cell can survive and reproduce independently
- Most bacteria reproduce by binary fission or budding
- Generation time varies greatly between species (e.g., Escherichia coli: 30 minutes, Mycobacterium leprae: 14 days)
Phases of Bacterial Growth
- Lag phase: no immediate increase in cell number, old cells depleted, and need time for synthesis of new cell components
- Exponential (log) phase: growth and division at maximum possible rate
- Stationary phase: growth ceases due to nutrient depletion and waste accumulation
- Death phase: severe nutrient deprivation, build-up of toxic waste products, and exponential decline in viable cell numbers
Bacterial Evolution
Types of Mutations
- Beneficial mutation: increases organism fitness
- Neutral mutation: no harmful or beneficial effect
- Harmful mutation: decreases organism fitness
Mechanisms of Bacterial Evolution
- Transformation: direct uptake of DNA through cell membrane
- Transduction: introduction of genetic material via a viral vector
- Conjugation: transfer of genetic material between two directly connected bacteria
Bacterial Evolution and Antibiotic Resistance
- Antibiotic usage can act as a selective pressure on bacteria, removing competition for resistant cells
- Unlikely to be due to a single mutation
Strain Improvement
- Initial strains may produce products at low concentrations, needing improvement
- Bacterial strains can improve naturally through spontaneous mutation
- Exposure to mutagens can increase frequency of mutation
- Genetic modification of organisms can improve yields
Heterologous Gene Expression
- Insulin was first produced in E. coli in 1978
- Cloned human insulin gene into E. coli
- Humulin and similar products have been in use for over 25 years
Microbial Metabolism
- Primary metabolism: energy production and release, cell component synthesis, and enzyme production
- Secondary metabolism: non-essential metabolic pathways, including production of natural products (e.g., antibiotics)
Laboratory Scale Culture
- Batch culture: closed system, limited nutrient availability, and limited product production
- Continuous culture: open system, nutrients supplied at a constant rate, and highly controlled growth
Viral Replication
- Relies on the subversion of host replication machinery
- True in both prokaryotic and eukaryotic viruses
- Lytic replication: leads to cell destruction (e.g., bacteriophages)
- Lysogenic replication: replicates alongside host, can enter lytic replication in favorable conditions
Learn about primary and secondary metabolism in microorganisms, including major metabolic pathways, energy production, enzyme production, and the production of natural products like antibiotics. Understand the differences between primary and secondary metabolism and their significance in microbial physiology.
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