Beneficial Activities of Microorganisms

A set of practice flashcards covering key concept over food chains, microbial roles, nutrient cycles, fermentation, bioremediation, and biotechnology.

What are the main trophic levels in a food chain from producers to tertiary consumers, and what does each level eat?

Producers create food (photosynthesis); Primary consumers (herbivores) eat producers; Secondary consumers (carnivores) eat primary consumers; Tertiary consumers eat secondary consumers. Decomposers recycle nutrients at all levels.

What are the two beneficial activities of microorganisms in the food chain, as described in the notes?

1) Producers via photosynthesis to make nutrients; 2) Decomposition/recycling of organic matter back into nutrients (nitrogen and other element cycles).

Name the organisms that act as producers in the microbiology context.

Plants, algae, and photosynthetic bacteria.

What elements of life are formed by inorganic versus organic compounds, and what are examples?

Inorganic compounds (formed mainly by ionic bonds) include water (H2O) and carbon dioxide (CO2); Organic compounds (formed by covalent bonds) include proteins, carbohydrates, lipids, and nucleic acids (DNA/RNA).

How do the oxygen and carbon dioxide cycles operate with photosynthesis and respiration?

Photosynthesis (producers) CO2/water to sugars/O2. Respiration (producers/consumers) sugars to energy/CO2/water. Microbes aid cycling they decompose organic matter and facilitate gas exchange.

What is nitrogen fixation and why is it essential for life?

Nitrogen fixation is the conversion of atmospheric N2 into usable forms (NH3, NH4+, NO2-, NO3-) for incorporation into amino acids, nucleotides, and ATP. It is performed abiotically (lightning) and biotically by microbes such as Azotobacter, Rhizobium (in legumes), and Nitrosomonas/Nitrobacter in soils.

What are nitrification and denitrification in the nitrogen cycle?

Nitrification is the oxidation of ammonia first to nitrite (NO2-) by organisms like Nitrosomonas and then to nitrate (NO3-). Denitrification is the conversion of nitrates back to nitrogen gas (N2), returning nitrogen to the atmosphere.

Which cellular components require nitrogen, making it essential for life?

Nitrogen is needed for amino acids (proteins), nucleotides (DNA/RNA), nitrogenous bases, and ATP.

What roles does the gut microbiota, especially E. coli, play in humans?

Synthesis of vitamin K and B vitamins; contribution to energy metabolism; helps maintain gut health when confined to the intestinal tract (infection risk if displaced).

Define fermentation and list its common products.

Fermentation is anaerobic metabolism that produces acids, alcohols, and gases; common products include lactic acid (yogurt), ethanol, and carbon dioxide.

Describe how yogurt is produced and the role of lactose.

Milk is pasteurized to kill pathogens, cooled, inoculated with yogurt starter cultures (lactic acid bacteria), and incubated to ferment lactose (milk sugar) into lactic acid, forming yogurt.

What distinguishes kefir from yogurt?

Kefir is a fermented dairy drink with a more diverse microbial community (grains), leading to greater microbial diversity than yogurt.

Give examples of industrial fermentation products and the microbes involved.

Acetic acid (vinegar) produced by Acetobacter; Ethanol produced by yeast in beer/wine; Lactic acid produced by lactic acid bacteria in yogurt and other fermented foods.

How do microbial enzymes affect cotton processing and textiles?

Microbial cellulases (e.g., from Trichoderma) break down cellulose to soften cotton fibers; this is a textile application of microbiology.

What is bioremediation and provide an example?

Bioremediation uses microorganisms to degrade environmental pollutants, such as oil spills; engineered microbes can speed the process in some cases.

What is Bacillus thuringiensis (Bt) used for in pest control?

Bt is used as a biological pesticide that produces toxins to kill certain insect pests.

What is fecal microbiota transplantation (FMT) and its purpose?

Transplanting healthy donor gut microbiota to restore normal gut flora in patients with C. difficile infection or gut dysbiosis.

How are microbes used in biotechnology beyond fermentation?

Microbes are used to produce vaccines, hormones, and in gene editing; Escherichia coli is a common lab organism due to rapid growth and a simple genome.

Describe the role of microbes in sewage treatment.

Microbes break down organic waste during sewage treatment, helping to remove solids and purify the water for safe discharge or reuse.

What notable fact about soil bacteria abundance is mentioned in the notes?

There are more bacteria in soil than there are cells in the human body; a teaspoon of soil contains billions of microorganisms.