Fungi are eukaryotic organisms, containing membrane-bound organelles, and they may be unicellular like yeasts or multicellular.  Fungi include molds, mushrooms, and yeast. A mushroom refers to a macroscopic fruiting body of basidiomycetes or ascomycetes. Yeast is unicellular fungi. 

(source)

Yeast is a single-celled fungus that can survive in the absence of oxygen by producing alcohol and CO2 as waste material. It helps in the rising of dough by producing CO2 that gets trapped in the dough.  Yeast can be found on fruit and berries, in the stomach of mammals and on skin, among other places. Although helpful, yeast can ause infection in individuals with compromised immune systems.

Algae are a diverse group of aquatic organisms that have the ability to conduct photosynthesis. Algae are a type of plant that do not produce seeds and do not have roots, stems, or leaves. Certain algae are familiar to most people; for instance, seaweeds (such as kelp or phytoplankton), pond scum or the algal blooms in lakes. However, there exists a vast and varied world of algae that are not only helpful to us, but are critical to our existence. 

(source)

Rotifers get their name (derived from Latin and meaning "wheel-bearer"; they have also been called wheel animalcules) from the corona, which is composed of several ciliated tufts around the mouth that in motion resemble a wheel. These create a current that sweeps food into the mouth, where it is chewed up by a characteristic pharynx (mastax) containing tiny jaws. It also pulls the animal, when unattached, through the water.Most free-living forms have pairs of posterior toes to anchor themselves while feeding.

(source)

Lactobacillus is a microorganism better known as Probiotics. Lactobacillus acidophilus helps the digestive system function correctly. Probiotics are a living bacterium that can help the body absorb nutrients and keep a healthy balance of beneficial bacteria. Conditions like lactose

intolerance, eczema, asthma, and irritable bowel syndrome can be treated using probiotics. You can find lactobacillus in Greek yogurt, and it can be taken

in tablet form. Lactobacillus may also cause arthritis, bloating, blockage of a lung artery, diseases of the esophagus, heart inflammation, liver infection, skin

reactions, stomach cramping, stomach lining inflammation, and stomach rumbling.

Probiotics are live microorganisms that are intended to have health benefits when consumed or applied to the body. They can be found in yogurt and other fermented foods, dietary supplements, and beauty products. A benefit of probiotics is the treatment of lactose intolerance.

Although people often think of bacteria and other microorganisms as harmful “germs,” many are actually helpful. Some bacteria help digest food, destroy disease-causing cells, or produce vitamins. Many of the microorganisms in probiotic products are the same as or similar to microorganisms that naturally live in our bodies.

(source)

Coronaviruses are a type of virus. There are many different kinds, and some cause disease. The coronavirus is spread through droplets and virus particles released into the air when an infected person breathes, talks, laughs, sings, coughs or sneezes. Larger droplets may fall to the ground in a few seconds, but tiny infectious particles can linger in the air and accumulate in indoor places, especially where many people are gathered and there is poor ventilation. Research continues, and more studies may reveal how and why the coronavirus evolved to cause pandemic disease.

(source)

Salmonella a type of harmful bacteria that can make you sick and cause food poisoning. It infects about 1.35 million people in the U.S. every year. Salmonella can be quite serious, especially for those who are very old, very young, or already sick. The illness sends thousands of people to the hospital each year. Sometimes it's life-threatening.

You most often get salmonella when you eat or drink something that has the bacteria in it. It's more common in food that comes from animals, like eggs, beef, and poultry. But soil or  cteria from one food to another with your hands or with knives, boards, platters, and other kitchen tools. You can get the infection if you don't cook certain foods well enough.

(source)

Botulism (“BOT-choo-liz-um”) is a rare but serious illness caused by a toxin that attacks the body’s nerves and causes difficulty breathing, muscle paralysis, and even death. This toxin is made by Clostridium botulinum and sometimes Clostridium butyricum and Clostridium baratii bacteria. These bacteria can produce the toxin in food, wounds, and the intestines of infants.

The bacteria that make botulinum toxin are found naturally in many places, but it’s rare for them to make people sick. These bacteria make spores, which act like protective coatings. Spores help the bacteria survive in the environment, even in extreme conditions. The spores usually do not cause people to become sick, even when they’re eaten. But under certain conditions, these spores can grow and make one of the most lethal toxins known

(source)

Tiny animals with an outsized ability to survive in harsh environments, tardigrades are widely used in scientific research. 

(source)

Listeriosis is a serious infection usually caused by eating food contaminated with the bacterium Listeria monocytogenes - food poisoning. An estimated 1,600 people get listeriosis each year, and about 260 die. The infection is most likely to sicken pregnant women and their newborns, adults aged 65 or older, and people with weakened immune systems.

(source)

Before smallpox was eradicated, it was a serious infectious disease caused by the variola virus. It was contagious—meaning, it spread from one person to another. People who had smallpox had a fever and a distinctive, progressive skin rash.

(source)

When toxic cyanobacteria take over an aquatic ecosystem, it collects and forms a thick carpet near the surface. This is called an algal bloom. Toxic algae blooms are harmful microorganisms that can discolor seawater and lower the level of oxygen in the water. The microorganisms in an algal bloom block the light from the Sun but still absorb its heat. Plants in the water will not receive enough sunlight and their populations will decrease. 

Penicillium mold creates an antibiotic. Antibiotics are chemicals that kill or inhibit the growth of bacteria and are used to treat bacterial infections. Antibiotics are made to fight bacterial infectious microorganisms. The creation of an antibiotic is the result of a beneficial microorganism. They are produced in nature by soil bacteria and fungi. This gives the microbe an advantage when competing for food and water and other limited resources in a particular habitat, as the antibiotic kills off their competition

(source)

Escherichia coli (known as E. coli) is a group of bacteria that typically lives in the intestines of humans and animals and helps keep our guts healthy. E-coli is a helpful microorganism that can cause harm outside of its natural environment of intestines. Certain types of this bacteria, however, can occasionally cause severe illness, according to the Centers for Disease Control and Prevention (CDC).

The types of E. coli that cause the majority of harmful infections in the U.S. produce a toxin called Shiga, and are appropriately called Shiga-toxin-producing E. coli (STEC).

(source)