Harmful and Beneficial Microorganisms Quiz and Flashcards

Study Notes

Microorganisms are tiny organisms that cannot be seen with the naked eye, including bacteria, fungi, protozoa, algae, and viruses. These single-celled organisms play essential roles in our lives, both beneficial and harmful. In this article, we will explore how these microscopic creatures impact our health, food production, and environment.

Beneficial Microorganisms

Beneficial microorganisms, also known as probiotics, are live bacteria and yeasts that are good for your digestive system. They help break down food, crowd out harmful bacteria, boost immunity, and manufacture some vitamins. Some common examples include Lactobacillus acidophilus, Bifidobacterium bifidum, and Saccharomyces boulardii. Probiotics can be found in fermented foods like yogurt, cheese, sauerkraut, miso soup, sourdough bread, and pickles.

Beyond gut health, beneficial microorganisms contribute to various industries:

Biofertilizers enhance plant growth by converting atmospheric nitrogen into ammonia which is absorbed by plants
Bioremediation uses microbes to break down pollutants and return them to their natural state
Sewage treatment relies on bacterial action to decomposes waste products before releasing treated water back into the environment
Industrial enzymes produced by microorganisms have applications in laundry detergents, dishwashers, food processing, baking, dairy manufacturing, textile industry, paper pulp bleaching, leather processing, and animal feed processing

Harmful Microorganisms

Harmful microorganisms, such as pathogenic bacteria, fungi, parasites, and viruses, can cause diseases ranging from mild symptoms like colds to severe illnesses like tuberculosis and AIDS. For example, Escherichia coli (E.coli), Staphylococcus aureus (Staph), Streptococcus pyogenes (strep throat), Pseudomonas aeruginosa (P. aeruginosa), and Clostridium difficile (C. diff) are all pathogens that can lead to serious health problems if they enter the body.

Some microorganisms produce toxic compounds called mycotoxins. These toxins are released when spores burst in the soil or when a mold grows on crops like grapes, corn, peanuts, barley, coffee beans, rice, wheat, oats, soybeans, and cottonseed. Mycotoxin exposure can lead to respiratory symptoms, skin rashes, nausea, vomiting, diarrhea, fever, kidney damage, liver damage, jaundice, permanent brain damage, allergies, and cancer.

Microbial Interactions

Microorganisms interact with each other, often forming complex communities. One organism's waste product may serve as another's nutrient source. These interactions help maintain ecological balance within ecosystems. Over 99% of species of most types of organisms are not classified as pests but rather as part of the total community of life on Earth. Some key microbial interactions include:

Mutualistic: Two partners benefit from their symbiotic relationship, like lichens where the fungus gets energy from photosynthesis while providing shelter and nutrients to the photosynthetic partner. Other mutualistic relationships include bees and flowering plants.
Commensal: One species benefits from the presence of others without affecting them negatively, such as epiphytes growing on tree branches.
Indirectly commensal: Organisms indirectly benefit through interactions between their hosts, where neither host is affected positively nor negatively by the interaction, like photosynthetic bacteria living on the surface of freshwater chironomids.

Microbial Diseases

While many microorganisms offer health benefits, others pose threats. Bacterial infections range from strep throat caused by Streptococcus pyogenes to tetanus by Clostridium tetani. Fungal diseases include thrush caused by Candida albicans and ringworm caused by Trichophyton spp. Parasitic diseases encompass malaria caused by Plasmodium falciparum and leprosy caused by Mycobacterium leprae. Viral diseases span from influenza caused by influenza virus to HIV causing acquired immune deficiency syndrome (AIDS).

Role of Microorganisms in Ecosystems

Microorganisms play significant roles in ecosystems, contributing to processes like decomposition, nutrient cycling, and organic matter breakdown. They break down dead organic material, turning it into nutrients that can then be used by plants for growth. This process helps recycle nutrients back into the ecosystem, maintaining healthy soil composition.

In aquatic environments, microorganisms are responsible for breaking down organic matter underwater, providing nutrients for primary producers like phytoplankton. They help control populations of other species by consuming excess biomass and recycling nutrients. In marine systems, planktonic bacteria are crucial for nitrate removal and remineralization of sediments to sustain biodiversity.

Understanding the interplay between beneficial and harmful microorganisms, their interactions, and their impacts on human health and ecosystems is essential for developing strategies to mitigate adverse outcomes and maximize benefits.

Description

Test your knowledge on how microorganisms, including beneficial probiotics and harmful pathogens, impact human health, food production, and the environment. Explore their roles in biofertilizers, bioremediation, sewage treatment, industrial enzyme production, diseases, microbial interactions, and ecosystems.