Biological Agents: Overview, Topics, Services, Examples
Biological agents include bacteria, viruses, fungi, toxins, and vectors that affect human, plant, and animal health. They are capable of harming humans in different ways, from very allergic reactions to major medical conditions, even death. They can cause diseases like anthrax, smallpox, and psittacosis and many others. Many can pass from person to person, either directly or indirectly.
This Story also Contains
- What Are Biological Agents?
- How Do Biological Agents Affect Us?
- Types of Biological Agents
- Biological Control Agents
- Biological Toxins
- Biological Vectors
- Applications and Risks of Biocontrol Agents
- Biological Agents NEET MCQs
- FAQs on Biological Agents
While useful in biocontrol and bioremediation, they can sometimes be turned into weapons and used in bioterrorism and other crimes as they are capable of harming human health in several different ways. Biological agents include bacteria, viruses, fungi, toxins, and vectors that affect living organisms. Learn types, examples, risks, FAQs, and NEET MCQs for Class 12 Biology.
What Are Biological Agents?
Microorganisms and poisons originating from biological sources that can be intentionally used as weapons in biological warfare or bioterrorism are referred to as biological agents. While some of these agents are specifically developed in labs, the majority of these agents are prevalent in the natural environment. The health of humans could be harmed by biological agents. From minor allergic reactions to death, debilitation, and disability, effects can range widely. Not only humans, other animals and plants can be affected as well.
How Do Biological Agents Affect Us?
The effects of the majority of biological agents take a long time to manifest and are generally unnoticeable. Because most plants and animals are susceptible to the effects of biological agents, they can also harm them. In the past, biowarfare techniques have included the use of fungi, plants, animal and human corpses, feces, and even disease-infected clothing.
Types of Biological Agents
The following categories can be used to group biological agents:
Bacteria Agents
Chlamydial Agents
Rickettsial Agents
Viral Agents
Mycotic Agents
Biological Toxins
Biological Vectors
Bacterial Agents
These "bio-agents" are, as their name implies, bacteria. The following are a handful of the most popular bacterial bioagents:
Anthrax bacteria (Anthrax)
Virus of cholera (Cholera)
Diphtheria-causing Corynebacterium (Diphtheria)
Chlamydial Agents
Chlamydophila psittaci is one of the most powerful chlamydial biological agents. A zoonotic infectious illness called Psittacosis is brought on by this bacteria. As it is spread by diseased parrots like macaws and cockatiels, it is also known as parrot fever or ornithosis.
Rickettsial Agents
Biological agents caused by Rickettsia include:
Cronobacter burnetii (Q Fever)
Prowazekii Rickettsii (Typhus)
Viral Agents
Several well-known viral agents are:
Viral encephalitis in Japan (Japanese B encephalitis)
The virus causing Rift Valley fever (Rift Valley fever)
Virus Variola (Smallpox)
Mycotic Agents
A mycotic biological agent is coccidioides immitis. It results in the illness of Coccidiomycosis (also known as desert rheumatism and Valley fever).
Biological Control Agents
Biocontrol agents are natural and eco-friendly. They do not harm humans, animals, or crops. These agents help maintain ecological balance. Here are some biocontrol agents that control pests and weeds:
Fungi
Predators
Bacteria
Virus
Parasitoids
FUNGI
One element of quick biocontrol techniques that does not harm the environment is fungi.
More so than chemical fertilisers and pesticides, it has demonstrated efficacy in managing pesticides.
One method of preventing pest infestations of green peach aphids is entomophagy (fungi).
PREDATORS
Predators eat a lot of other organisms and continue to exist as free-living creatures.
The biocontrol agents include predators including spiders, dragonflies, lacewings, lady beetles, etc.
BACTERIA
Coccobacillus bacteria are thought to be the best bacteria for weed and pest management.
Another kind of bacterium is soil-dwelling Bacillus Thuringiensis.
VIRUS
A virus may be a powerful biocontrol tool and can help bugs choose their precise targets.
Researchers are continuing working on developing a virus that would selectively target pests and perform biological control.
Baculovirus and nucleopolyhedro virus are two examples.
PARASITOIDS
By laying eggs, it may kill the host since the larvae need the host for feeding.
Examples of parasitoids are wasps and beetles.
One type of wasp that lays an egg within an aphid species is the Aphidius colemani. The aphid dies as a result of the larvae obtaining energy from it.
Biological Toxins
As the name implies, biological toxins are the poison that are extracted from living things. The following are some of the most potent:
Ricin (from castor bean - Ricinus communis) (from castor bean – Ricinus communis)
Tetrodotoxin (from several marine microorganisms) (from various marine bacteria)
Botulinum poisoning (from bacteria – Clostridium botulinum)
Commonly Asked Questions
Biopesticides are derived from natural materials like animals, plants, bacteria, and certain minerals. Microorganisms such as Bacillus thuringiensis (Bt) act as biological agents, producing proteins toxic to specific insect pests. These biopesticides offer more targeted pest control with fewer environmental impacts compared to broad-spectrum chemical pesticides.
Bioherbicides use living organisms or their products to control weeds. Certain fungi and bacteria act as biological agents, producing compounds toxic to specific weed species or competing with them for resources. These natural alternatives to chemical herbicides offer more targeted weed control with potentially fewer environmental side effects.
Biological Vectors
Biological vectors transport the pathogens that cause illness. The most popular include:
Mosquitos (Yellow fever, Malaria, Dengue) (Yellow fever, Malaria, Dengue)
Flea Rat (Plague)
Applications and Risks of Biocontrol Agents
Biological agents are living organisms or their byproducts that can be used to cause disease, death, or other harm to a population or environment. They include bacteria, viruses, fungi, protozoa, and toxins, and can be released deliberately as weapons of mass destruction or accidentally as a result of a natural disaster.
Biological agents can be highly contagious and may cause severe morbidity and mortality if left untreated. In some cases, biological agents can be used to create bioweapons, which are weapons that use infectious agents to cause harm or death.
Biological agents can also be used to create bioterrorism, which is the intentional use of infectious agents to cause harm or death.
Biological agents can be used to create biocontrols, which are organisms used to control the population of other organisms.
Additionally, biological agents can be used in bioremediation, which is the use of microorganisms to clean up environmental contamination.
Biological Agents NEET MCQs
Q1. Anthrax is caused by which biological agent?
a) Virus
b) Fungus
c) Bacteria
d) Protozoa
Correct answer: c) Bacteria
Explanation:
Anthrax is caused by the bacterium Bacillus anthracis, a Gram-positive, spore-forming rod. Its durable spores can persist in soil for decades and infect grazing animals, with humans exposed through contact with infected animals or animal products. Clinical forms include cutaneous (black eschar), inhalational (severe respiratory illness), and gastrointestinal anthrax. Key virulence factors include a poly-D-glutamate capsule and exotoxins (protective antigen, edema factor, lethal factor). Because the etiologic agent is unequivocally bacterial, the virus, fungus, and protozoa options are incorrect.
Hence, the correct answer is c) Bacteria.
Q2. Psittacosis (parrot fever) is caused by:
a) Virus
b) Chlamydial agent
c) Mycotic agent
d) Protozoan parasite
Correct answer: b) Chlamydial agent
Explanation:
Psittacosis, also called parrot fever or ornithosis, is a zoonotic infection caused by Chlamydia psittaci, an obligate intracellular chlamydial bacterium transmitted mainly from birds (parrots, pigeons, poultry). In humans it typically presents as an atypical pneumonia with fever, dry cough, and systemic features. It is not viral, fungal (mycotic), or protozoan in origin, which rules out the other choices. Recognition of its chlamydial nature guides appropriate public health measures and antibiotic therapy.
Hence, the correct answer is b) Chlamydial agent.
Q3. Which of the following is a biological toxin?
a) Ricin
b) Anthrax
c) Cholera
d) Smallpox
Correct answer: a) Ricin
Explanation:
Ricin is a highly potent protein toxin derived from the castor bean (Ricinus communis). It inactivates ribosomes by depurinating 28S rRNA, thereby halting protein synthesis and leading to cell death; it is toxic but not infectious. By contrast, anthrax is caused by the bacterium Bacillus anthracis, cholera by the bacterium Vibrio cholerae (which produces cholera toxin but the disease itself is bacterial), and smallpox by the variola virus. Thus, among the options, only ricin is itself a biological toxin rather than an infectious organism.
Hence, the correct answer is a) Ricin.
Also Read:
FAQs on Biological Agents
What are biological agents?
Biological agents are microorganisms, such as bacteria, viruses, fungi, and protozoa, that can be used for beneficial purposes in various fields like agriculture, medicine, and industry. These agents are harnessed for their natural abilities to perform specific functions or produce useful substances.
What are examples of biological agents?
Biological agents consist of bacteria, viruses, fungi (such as yeasts and molds), and protozoa. They can cause mild infection or serious conditions leading to death. Some of them are beneficial as well.
What are biological control agents?
Biocontrol agents are the living organisms that are used to suppress pests in agriculture. Biological agents like predatory insects, parasitoids, or microorganisms that cause diseases. This approach reduces dependence on chemical pesticides and is more targeted and environmentally friendly. Example: Ladybird beetles, Trichoderma fungi, and Bacillus thuringiensis.
What are biological toxins?
Biological toxins are poisonous substances that are produced by microorganisms, plants, or animals that can harm or kill living cells. Examples of biological toxins include Botulinum toxin, ricin, and aflatoxins.
Frequently Asked Questions (FAQs)
Biogas production involves anaerobic digestion of organic matter by various microorganisms. These biological agents break down complex organic compounds in the absence of oxygen, producing a mixture of gases (primarily methane and carbon dioxide) that can be used as a renewable energy source.
Citric acid is primarily produced through fermentation using the fungus Aspergillus niger. This biological agent efficiently converts sugar-containing substrates into citric acid. The process is widely used in industry due to its cost-effectiveness and high yield compared to chemical synthesis methods.
Certain bacteria and fungi produce cellulase enzymes that can break down cellulose into simpler sugars. These biological agents are used in various industries, including biofuel production (to break down plant biomass), textile manufacturing (to soften fabrics), and paper production (to improve pulp properties).
Many amino acids are produced industrially using bacterial fermentation. Genetically modified strains of bacteria, such as Corynebacterium glutamicum, are used as biological agents to efficiently convert simple sugars or other substrates into specific amino acids. This process is used for producing food additives, animal feed supplements, and pharmaceutical ingredients.
Biological agents, primarily bacteria and fungi, are used in the treatment of industrial wastewater. These microorganisms break down organic pollutants, remove heavy metals, and reduce the overall toxicity of effluents. This biological treatment is often more cost-effective and environmentally friendly than chemical treatment methods.
Various microorganisms act as biological agents in promoting plant growth. For example, Azospirillum bacteria can fix nitrogen and produce plant hormones, while certain fungi produce gibberellins. These biological agents are used to develop biofertilizers and plant growth stimulants for sustainable agriculture.
Certain bacteria and fungi have been identified that can degrade various types of plastics. These microorganisms produce enzymes that break down plastic polymers into simpler compounds. Research is ongoing to harness these biological agents for more effective plastic waste management and recycling.
Certain microorganisms act as biological agents in controlling plant pathogens. For example, Trichoderma fungi can parasitize other fungi that cause plant diseases. These beneficial microbes are cultivated and used as biocontrol agents, offering an alternative to chemical fungicides in crop protection.
Microorganisms play crucial roles in converting lignocellulosic biomass (like wood or grass) into biofuels. Fungi and bacteria produce enzymes that break down complex plant materials into simple sugars. Other microorganisms then ferment these sugars into ethanol or other biofuels. This process allows the utilization of non-food plant materials for fuel production.
Certain bacteria, such as Acidithiobacillus ferrooxidans, can be used as biological agents to treat acid mine drainage. These microorganisms oxidize dissolved metals and sulfur compounds, precipitating them out of solution. This biotreatment approach helps in reducing the environmental impact of mining activities.
