Virus and Bacterial Classification Quiz
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Questions and Answers

What distinguishes viruses classified as DNA viruses from those classified as RNA viruses?

  • The type of host organisms they infect
  • The method of replication they use
  • The chemical structure of their nucleic acids (correct)
  • The size of the viral particles

Which of the following statements is true regarding the classification of viruses?

  • DNA viruses can combine RNA to form hybrid viruses.
  • All viruses have the same replication methods regardless of nucleic acid type.
  • RNA viruses are generally larger than DNA viruses.
  • Viruses can be classified based solely on their nucleic acid type. (correct)

What characteristic is NOT a basis for the classification of viruses?

  • The shape of the viral capsid
  • The source of their replication (correct)
  • The type of genetic material they contain
  • The presence of an envelope

Which of these characteristics could lead to confusion in viral classification?

<p>Some viruses possess both DNA and RNA. (A)</p> Signup and view all the answers

Which of these factors is most likely to influence the evolutionary pathway of DNA viruses?

<p>The stability of their genetic material (A)</p> Signup and view all the answers

In virus classification, what does the designation 'RNA virus' primarily indicate?

<p>The structure and stability of its nucleic acids (B)</p> Signup and view all the answers

What factor primarily differentiates how RNA viruses replicate compared to DNA viruses?

<p>RNA viruses can undergo translation directly from their genetic material. (C)</p> Signup and view all the answers

Which of the following is a characteristic feature of bacterial growth?

<p>Bacteria reproduce through binary fission, leading to exponential growth. (C)</p> Signup and view all the answers

What factor is most likely to influence the rate of bacterial growth?

<p>Oxygen levels in the environment. (A)</p> Signup and view all the answers

During bacterial growth, which phase is characterized by the rapid increase in the number of cells?

<p>Log phase, when cells divide at a constant rate. (C)</p> Signup and view all the answers

What is a common misconception regarding the nutrient requirements for bacterial growth?

<p>Some bacteria can grow in minimal nutrient conditions. (C)</p> Signup and view all the answers

Which statement about the environmental conditions affecting bacterial growth is false?

<p>pH levels have no effect on bacterial metabolism. (B)</p> Signup and view all the answers

What key enzyme is found in RNA viruses, particularly retroviruses?

<p>Reverse transcriptase (D)</p> Signup and view all the answers

Which of the following statements is true regarding RNA viruses?

<p>They have a broad range of host organisms. (C)</p> Signup and view all the answers

What is a characteristic feature of retroviruses?

<p>They integrate their genetic material into the host DNA. (B)</p> Signup and view all the answers

Which of the following is a common misconception about RNA viruses?

<p>They can only infect humans. (D)</p> Signup and view all the answers

How do retroviruses primarily replicate their genetic material?

<p>Reverse transcription of RNA to DNA (C)</p> Signup and view all the answers

Which of these viruses could be considered a retrovirus?

<p>HIV (C)</p> Signup and view all the answers

What impact does reverse transcriptase have in the lifecycle of a retrovirus?

<p>It converts viral RNA into DNA for integration. (D)</p> Signup and view all the answers

What distinguishes retroviruses from other RNA viruses?

<p>The use of reverse transcriptase. (D)</p> Signup and view all the answers

What type of genetic material do retroviruses primarily use?

<p>Single-stranded RNA (D)</p> Signup and view all the answers

What is the primary challenge pathogens must overcome to establish infection?

<p>Penetrate tissues and withstand defenses (A)</p> Signup and view all the answers

Which of the following is NOT a characteristic of diseases caused by pathogens?

<p>Resistance to all treatments (D)</p> Signup and view all the answers

Why is it important for pathogens to penetrate tissues?

<p>To access nutrient-rich environments (C)</p> Signup and view all the answers

What is a common method through which pathogens induce illness?

<p>Releasing toxins or damaging host cells (D)</p> Signup and view all the answers

Which factor does NOT play a role in a pathogen's ability to withstand defenses?

<p>Higher metabolic rate (B)</p> Signup and view all the answers

What is typically a critical first step in the infectious process of a pathogen?

<p>Adhering to host tissues (A)</p> Signup and view all the answers

What mechanism do many pathogens utilize to penetrate host tissues?

<p>Enzymatic degradation of host barriers (B)</p> Signup and view all the answers

Which of the following describes a method of pathogen transmission?

<p>Through contaminated food and water (A)</p> Signup and view all the answers

Which statement about the relationship between pathogens and hosts is true?

<p>Some pathogens can remain dormant in hosts (D)</p> Signup and view all the answers

Which of the following best describes how a pathogen induces illness?

<p>By disrupting normal cellular functions and processes (D)</p> Signup and view all the answers

What characteristic distinguishes Gram Positive bacteria from Gram Negative bacteria?

<p>Appearance color after Gram staining (B)</p> Signup and view all the answers

Which statement is true regarding Gram Negative bacteria?

<p>They possess an outer membrane. (A)</p> Signup and view all the answers

What is the typical shape of Gram Negative bacteria discussed in this content?

<p>Spirillum (A)</p> Signup and view all the answers

What color do Gram Negative bacteria appear after the Gram staining process?

<p>Pink (B)</p> Signup and view all the answers

Which of the following is NOT a feature of Gram Positive bacteria?

<p>Presence of an outer membrane (A)</p> Signup and view all the answers

Which property of Gram Positive bacteria contributes to their color during Gram staining?

<p>Their thick peptidoglycan layer (B)</p> Signup and view all the answers

In distinguishing bacterial types, what is a primary factor contributing to the staining results?

<p>Differences in cell wall structure (C)</p> Signup and view all the answers

Which of the following shapes is associated with Gram Positive bacteria?

<p>Cocci (B)</p> Signup and view all the answers

What type of peptidoglycan layer do Gram Positive bacteria have?

<p>Thick (D)</p> Signup and view all the answers

What do Gram Positive and Gram Negative bacteria have in common?

<p>Both have peptidoglycan layers (C)</p> Signup and view all the answers

What is the main purpose of a selective medium in microbial culture?

<p>To suppress the growth of unwanted micro-organisms (B)</p> Signup and view all the answers

Which process is primarily responsible for the exponential growth of bacteria in a nutrient medium?

<p>Binary fission (C)</p> Signup and view all the answers

During which phase of bacterial growth does the cell adaptation occur before division begins?

<p>Lag phase (D)</p> Signup and view all the answers

What is a common reason for the stationary phase in a bacterial growth curve?

<p>Competition for resources (C)</p> Signup and view all the answers

What role do antibiotics play in treating bacterial infections?

<p>They interfere with bacterial metabolism or growth (C)</p> Signup and view all the answers

Which type of medium allows the growth of specific micro-organisms by adding certain substances?

<p>Enrichment medium (A)</p> Signup and view all the answers

Which mechanism is NOT involved in the action of antibiotics against bacteria?

<p>Stimulation of bacterial reproduction (C)</p> Signup and view all the answers

What is one of the results of the decline phase of bacterial growth?

<p>Death rate surpasses growth rate (C)</p> Signup and view all the answers

What kind of technique is employed to prevent contamination during microbial experimentation?

<p>Aseptic technique (A)</p> Signup and view all the answers

Which of the following does NOT directly affect bacterial growth?

<p>Time of day (C)</p> Signup and view all the answers

Which characteristics enable a bacterium to be considered a pathogen?

<p>Capacity to induce illness in the host (C)</p> Signup and view all the answers

What is a unique feature of the lysogenic life cycle of viruses?

<p>The viral genome is integrated into the host's genome (B)</p> Signup and view all the answers

Which statement accurately describes Gram staining?

<p>It distinguishes bacteria by the thickness of their peptidoglycan layer (A)</p> Signup and view all the answers

What role do antibiotics play in healthcare?

<p>They kill or inhibit the growth of bacteria without harming human cells (D)</p> Signup and view all the answers

Which bacterium is responsible for causing peptic ulcers?

<p>Helicobacter pylori (B)</p> Signup and view all the answers

What is a major difference between Gram Positive and Gram Negative bacteria?

<p>Gram Positive bacteria have a thicker peptidoglycan layer (D)</p> Signup and view all the answers

What is the primary function of peptidoglycan in bacterial cells?

<p>To provide structural integrity and shape (B)</p> Signup and view all the answers

Which disease is caused by the bacterium Mycobacterium tuberculosis?

<p>Tuberculosis (D)</p> Signup and view all the answers

What common misconception exists about pathogenic bacteria?

<p>All bacteria are harmful to humans (D)</p> Signup and view all the answers

Which of the following statements is FALSE regarding bacteria?

<p>All bacteria cause disease in humans (A)</p> Signup and view all the answers

What kind of genetic material do most viruses possess?

<p>Nucleic acid (D)</p> Signup and view all the answers

Which lifecycle describes a viral infection that does not cause immediate destruction of the host cell?

<p>Lysogenic cycle (C)</p> Signup and view all the answers

Why are viruses considered nonliving entities?

<p>They do not exhibit metabolic processes outside of a host. (C)</p> Signup and view all the answers

What is the role of reverse transcriptase in RNA viruses?

<p>To convert RNA into DNA. (B)</p> Signup and view all the answers

Which of the following components is consistently found in the structure of a virus?

<p>Capsid (C)</p> Signup and view all the answers

What discovery did Dimitri Ivanowsky make regarding viruses?

<p>Viruses can be filtered through fine-pore filters. (A)</p> Signup and view all the answers

What characterizes a virus as a retrovirus?

<p>It synthesizes DNA from RNA. (B)</p> Signup and view all the answers

What is a significant consequence of the lytic life cycle for the host cell?

<p>The host cell is destroyed after viral replication. (B)</p> Signup and view all the answers

Which type of viruses undergo a lifecycle that integrates with the host's DNA?

<p>Lysogenic viruses (B)</p> Signup and view all the answers

What is the primary structural difference between the influenza virus and HIV?

<p>Influenza virus primarily has RNA. (D)</p> Signup and view all the answers

What characteristic distinguishes fungi from plants?

<p>Fungi are heterotrophic. (D)</p> Signup and view all the answers

Which structure is NOT typically found in fungi?

<p>Cilia for movement (D)</p> Signup and view all the answers

What process do fungi primarily use for reproduction?

<p>Spore formation (C)</p> Signup and view all the answers

What is a primary function of hyphae in fungi?

<p>Nutrient absorption (B)</p> Signup and view all the answers

Which statement about the honey fungus Armillaria bulbosa is incorrect?

<p>It primarily reproduces through fragmentation. (C)</p> Signup and view all the answers

In which environment are fungi typically found thriving?

<p>In decaying organic matter (B)</p> Signup and view all the answers

Which characteristic is NOT true about fungal cell walls?

<p>Composed of proteins only (A)</p> Signup and view all the answers

What distinguishes the reproductive structures of large fungi such as mushrooms?

<p>They form fruiting bodies to release spores. (D)</p> Signup and view all the answers

What type of nutrition do fungi exhibit?

<p>Heterotrophic (A)</p> Signup and view all the answers

Which function does NOT apply to the role of fungi in agriculture?

<p>Nitrogen fixation (D)</p> Signup and view all the answers

Flashcards

DNA viruses

A category of viruses that use DNA as their genetic material.

RNA viruses

A category of viruses that use RNA as their genetic material.

Nucleic acid type classification

A system of categorizing viruses based on their type of nucleic acid, either DNA or RNA.

What are DNA viruses?

Viruses that use DNA as their genetic material.

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What are RNA viruses?

Viruses that use RNA as their genetic material.

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How are viruses classified based on nucleic acid type?

A system that sorts viruses into groups based on whether their genetic material is DNA or RNA.

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What are Gram-Positive bacteria?

Bacteria that have a thick peptidoglycan layer in their cell walls, which stains purple with the Gram stain.

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What are Gram-Negative bacteria?

Bacteria that have a thin peptidoglycan layer in their cell walls, which stains pink with the Gram stain.

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What is a coccus?

A spherical or round-shaped bacterium.

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What is a spirillum?

A spiral-shaped bacterium.

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What is antibiotic resistance?

The ability of a bacterium to resist the effects of an antibiotic.

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What is disinfection?

A process that kills or inhibits the growth of microorganisms on inanimate objects.

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What is an antiseptic?

A substance that kills or inhibits the growth of microorganisms.

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What is antisepsis?

A process that kills or inhibits the growth of microorganisms on living tissue.

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What is a pathogen?

A microorganism that causes disease.

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What is an antigen?

A substance that triggers an immune response in the body.

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What are retroviruses?

Retroviruses are a type of RNA virus that uses an enzyme called reverse transcriptase to convert their RNA genome into DNA.

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What is reverse transcriptase?

Reverse transcriptase is an enzyme used by retroviruses to convert their RNA genome into DNA. This allows the virus to integrate its genetic material into the host's genome.

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How do retroviruses replicate?

Retroviruses contain RNA as their genetic material, but they can integrate their DNA copy into the host's genome for replication.

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Can you name some examples of retroviruses?

Examples of retroviruses include HIV, which causes AIDS, and HTLV-1, which causes adult T-cell leukemia.

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What happens to the retroviral DNA after integration?

The DNA copy of the retrovirus genome can remain integrated in the host's genome, potentially leading to long-term effects.

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Why can retroviruses cause chronic infections?

Retroviruses can cause chronic infections because their genetic material can become a permanent part of the host's genome.

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What is integration in the context of retroviruses?

Integration is a process where the DNA copy of the retrovirus genome is incorporated into the host's genome, allowing for long-term persistence.

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What makes retroviruses unique?

Integration is a key feature of retroviruses and is distinct from how DNA viruses replicate, making them a unique category of viruses.

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How can retroviruses cause disease?

Retroviruses can cause disease by disrupting host cells and causing abnormalities in cellular functions, affecting the host's overall health.

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What is bacterial growth?

Bacterial growth refers to the increase in the number of bacteria in a population. It happens through a process called binary fission, where one bacterium divides into two identical daughter cells.

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What is bacterial generation time?

The generation time of bacteria is the time it takes for a bacterial population to double in size. This time can vary depending on the species and the environmental conditions.

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What is a bacterial growth curve?

Bacterial growth curve is a graphical representation of the changes in population size over time. It typically has four distinct phases: lag phase, exponential phase, stationary phase, and death phase.

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What is the lag phase in bacterial growth?

The lag phase is the initial period of bacterial growth where there is little or no increase in population size. The bacteria are adjusting to their new environment and preparing for rapid growth.

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What is the exponential phase in bacterial growth?

The exponential phase is the phase of rapid bacterial growth where the population size doubles at a constant rate. This occurs because the bacteria have adapted to their environment and are actively dividing.

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What are the four key steps for a pathogen to cause disease?

A pathogen must be able to pass from one host to another, invade and multiply within tissues, evade host defenses, and cause illness.

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What are some examples of diseases caused by viruses?

Examples include the common cold, influenza, measles, chickenpox, rabies, and HIV.

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How are bacteria classified based on their shape?

Bacteria can be classified based on their shape, including coccus (spherical), bacillus (rod-shaped), and spirillum (spiral).

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What is the difference between Gram-positive and Gram-negative bacteria?

Gram-positive bacteria have a thick peptidoglycan layer in their cell walls, making them stain purple with the Gram stain. Gram-negative bacteria have a thinner peptidoglycan layer, causing them to stain pink.

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What is a bacteriophage?

A virus that infects a bacterium. They are also known as phages.

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What is a lysogenic life cycle?

A viral life cycle where the host cell remains alive and continues to release virus particles slowly.

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What is a bacterium?

A single-celled organism lacking a nucleus and internal organelles. They have a cell wall made of peptidoglycan.

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What does it mean to be Gram-positive?

A thick layer of peptidoglycan in the cell wall, which stains purple with the Gram stain.

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What does it mean to be Gram-negative?

A thin layer of peptidoglycan in the cell wall, which stains pink with the Gram stain.

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What is a pathogenic bacterium?

A bacterium that can cause disease in a host.

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What is an antibiotic?

A drug that kills or stops the growth of bacteria without harming the host's cells.

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What are viruses?

Subcellular, nonliving particles that multiply only inside living cells. They have various shapes but share common features.

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What was the early evidence for viruses?

Louis Pasteur's idea that something smaller than bacteria caused rabies, later confirmed by Dimitri Ivanowsky's observations of tobacco mosaic disease.

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What is a viral capsid?

A protein coat surrounding the virus's DNA or RNA, sometimes with an envelope.

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How are viruses classified?

Viruses are classified based on their type of nucleic acid, either DNA or RNA.

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What is the lytic life cycle?

The viral infection cycle where the virus replicates within a cell, ultimately causing the cell to burst and release new viruses.

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What is the lysogenic life cycle?

The viral infection cycle where the virus's genetic material integrates into the host cell's DNA, allowing the virus to remain dormant or be released slowly.

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What is viral specificity?

The ability of a virus to infect a specific type of living cell or organism.

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How big are viruses?

Viruses are generally smaller than bacteria and are not visible with light microscopes. Electron microscopes are needed to observe their structure.

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Can viruses be stored?

Viruses can be purified and stored in a crystalline form, but become infectious when they find living cells to invade.

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What are antibiotics?

Antibiotics are drugs that interfere with the growth or metabolism of bacteria, targeting specific processes like cell wall synthesis, protein synthesis, or DNA/RNA replication.

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What is a culture medium?

A culture medium is a substance, typically liquid or solid, that provides nutrients for the growth of microorganisms, animal cells, or plant cells.

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What is enrichment media?

Enrichment media are designed to promote the growth of specific types of microorganisms by providing them with suitable nutrients or conditions. They favor certain microbial species over others.

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What is selective media?

Selective media are designed to allow the growth of only certain types of microorganisms by inhibiting the growth of others. They use specific ingredients or conditions to select for desired organisms.

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What is aseptic technique?

Aseptic technique is a set of practices used to manipulate microorganisms or sterile materials without introducing unwanted contaminants. Sterilization and preventing contamination are key.

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What is inoculation?

Inoculation is the process of introducing a small amount of microorganisms into a nutrient medium for cultivation and growth.

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How fast do bacteria grow?

In ideal conditions, bacteria can divide by binary fission every 30 minutes, resulting in exponential growth. One cell can produce millions of cells in a short time.

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What is the lag phase?

The lag phase is the initial phase of bacterial growth where cells are adapting to the new environment and preparing for rapid growth. They are not actively dividing yet.

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What is the log phase?

The log phase, often called the exponential phase, is the stage where bacteria grow and divide at the fastest rate. This period is characterized by rapid population growth.

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What are fungi?

Organisms that obtain energy and carbon from dead or decaying matter or by feeding as parasites on living organisms. They are characterized by their lack of chlorophyll, heterotrophic nutrition, and reproduction through spores.

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What are yeasts?

Microscopic, single-celled fungi used in various applications, including food production (bread and alcoholic beverages) and biotechnological processes.

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What are hyphae?

Long, thread-like structures that make up the bodies of most fungi. They may have crosswalls or be continuous, forming a network.

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What are fruiting bodies?

Large, compacted masses of hyphae that are specialized for reproduction in fungi. They are often what we see as mushrooms.

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What is chitin?

A complex carbohydrate that makes up the cell walls of fungi, giving them structural support.

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What is spore reproduction?

The process by which fungi reproduce by releasing microscopic units called spores. Spores can survive in harsh conditions and germinate into new fungi.

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What is decomposition by fungi?

Fungi play a crucial role in breaking down dead organic matter, recycling nutrients back into the ecosystem.

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How are fungi used in food production?

Fungi are often used in the production of fermented foods, such as cheese, bread, and alcoholic beverages.

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How are fungi used in biotechnology?

Certain fungi are utilized in biotechnology to produce valuable products, including antibiotics, enzymes, and biofuels.

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How can fungi be harmful?

Fungi can cause diseases in plants, animals, and humans. These diseases can range from mild infections to serious illnesses.

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