Microbial Metabolism and Nutrients Quiz

Microbial Metabolism

• Metabolism is a series of biochemical reactions where cells break down or synthesize various metabolites.
• Two types of metabolism exist:
  • Anabolism: Building larger molecules from smaller ones (e.g., amino acids to protein).
  • Catabolism: Breaking down larger molecules into smaller ones (e.g., protein to amino acids).
• Primary metabolism is crucial for survival, breaking down nutrients into basic forms.
• Secondary metabolism is involved in growth, reproduction, and survival.

Microbial Nutrients and Nutrient Uptake

• Nutrients are categorized into two types:
  • Macronutrients: Required in large amounts.
  • Micronutrients: Required in minute amounts.
• Uptake of nutrients involves crossing the cytoplasmic membrane. Active transport requires energy and moves molecules against the concentration gradient.
• Cell nutrition is dependent on both types of nutrients.

Chemicals in Predominant in Living Systems

• Carbon makes up 50% of a cell's dry weight.
• Oxygen and Hydrogen account for approximately 2% combined.
• Nitrogen represents 13% of a cell's dry weight.
• Phosphorus, Sulfur, Potassium, Magnesium, and Selenium make up less than 5% of dry weight.
• Water makes up 75% of wet weight.
• Primary macromolecules contribute the remaining portion of the wet weight.
• Protein constitutes 55% of the dry weight.
• Other macromolecular components include lipids, polysaccharides, lipopolysaccharides, DNA, and RNA.

Energy Classes of Microbes

• Chemotrophs use chemical energy as their source.
  • Chemoorganotrophs use organic chemicals.
  • Chemolithotrophs use inorganic chemicals.
• Phototrophs use light energy.
  • Photoautotrophs capture light energy to make their own food.
• Autotrophs: Use CO2 as a carbon source for synthesis.
• Heterotrophs: Obtain carbon from organic compounds.

Catalysis and Enzymes

• Activation energy is the minimum energy required for a chemical reaction to start.
• Exergonic reactions release energy.
• Endergonic reactions absorb energy.
• Catalysts, such as enzymes, speed up reactions by lowering the activation energy.

Energy-Rich Compounds

• Redox reactions release energy-rich phosphate compounds used by cells for functions such as ATP, Acetyl-CoA.
• Examples of these compounds include ATP, Acetyl-CoA, Acetyl Phosphate, Glucose 6-Phosphate, and Phosphoenolpyruvate.

Fermentation and Respiration

• Fermentation is an anaerobic catabolism where organic compounds both donate and accept electrons.
• Respiration is an aerobic or anaerobic catabolism where an organic or inorganic donor is oxidized and oxygen or another molecule acts as the acceptor.

Glycolysis

• Glyoxylate cycle is an alternative to fermentation, enabling glucose to proceed into respiration when ready.
• Glycolysis is a metabolic pathway that breaks down glucose to produce energy and smaller molecules.
  • The process encompasses three stages.
  • The first stage prepares glucose for the later stages.
  • The second stage involves redox reactions.
  • The third stage completes the conversion to pyruvate.

Microbial Interactions

• Symbiosis: A long-term biological interaction between two or more organisms of the same or different species.
  • Mutualism: Both species benefit.
  • Commensalism: One species benefits, while the other is neither harmed nor helped.
  • Parasitism: One species benefits, and the other is harmed.
• Competition: Rivalry for resources like space and nutrients.
• Antagonism: One species' products negatively impact another.
• Microbe-host interactions, including infection, colonization, and disease.
• Infectious agents can have virulence factors that enable them to evade host systems.

Additional Topics

• Microbial nutrient uptake and transport, simple transport, group translocation, ABC transport
• Autotrophs vs. Heterotrophs, Chemotrophs vs Phototrophs
• Enzymatic functions related to microbiology
• Fermentation: Various fermentation types and organisms involved.
• Bacterial interactions, including viruses, and biofilm formation.
• Energy balance sheet of aerobic respiration showing ATP yield at each stage
• Glyoxylate cycle
• Other innate host defenses such as inflammation, fever, and the roles of cytokines and Natural Killer cells (NK cells)
• Interferon’s role in combating viral replication
• Origin of mitochondria and chloroplasts
• Endosymbiotic Theory and Holobiont/Metaorganism Theory