Microorganisms Overview

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Questions and Answers

What characteristic distinguishes nematodes from other parasitic worms?

They have a body cavity.

They lack separate sexes.

They are segmented and flat.

They are bilaterally symmetrical with tapered ends. (correct)

Which of the following statements is true concerning cestodes?

Cestodes attach to hosts using a scolex with suckers or hooks. (correct)

Cestodes are unsegmented and leaf-like in shape.

Cestodes have no larval stages.

Cestodes have separate male and female sexes.

What is the primary habitat for free-living nematodes?

In the tissues of invertebrates.

In soil, freshwater, and marine environments. (correct)

In the blood of vertebrates.

Inside the intestines of mammals.

What feature is present in trematodes but absent in nematodes and cestodes?

Two suckers on the body. Signup and view all the answers

Which of the following best describes the life stages of cestodes?

All stages of cestodes are parasitic. Signup and view all the answers

What is a key feature that distinguishes bacteria from archaea?

Bacteria contain peptidoglycans in their cell walls. Signup and view all the answers

What method do bacteria primarily use for reproduction?

Binary fission Signup and view all the answers

Which group of archaea is known to thrive in extremely hot environments?

Thermophiles Signup and view all the answers

Which type of algae is known for producing a significant portion of Earth's atmospheric oxygen?

Cyanobacteria Signup and view all the answers

What characteristic is used to classify bacteria?

Shape of the organism Signup and view all the answers

What do phototrophic archaea utilize for energy production?

Light Signup and view all the answers

What type of locomotion is primarily associated with protozoa?

All of the above Signup and view all the answers

Which of the following is NOT a characteristic used to classify archaea?

Reproductive strategy Signup and view all the answers

Which type of locomotion does Giardia Lamblia utilize?

Flagellar movement Signup and view all the answers

What is the main structural feature of the cell wall in fungi?

Chitin Signup and view all the answers

What distinguishes dimorphic fungi from other fungi?

They exist as yeast or mould depending on temperature. Signup and view all the answers

Which of the following is NOT a mode of locomotion for protozoa?

Root-like anchoring Signup and view all the answers

How do fungi acquire nutrients?

By decomposing organic materials Signup and view all the answers

Which type of fungi reproduces by producing zygospores?

Zygomycetes Signup and view all the answers

What reproductive structure do yeast utilize for asexual reproduction?

Budding Signup and view all the answers

Which feature is NOT characteristic of sporozoans?

Utilize pseudopodia for movement Signup and view all the answers

Which type of fungi primarily reproduces asexually and lacks a known sexual reproductive stage?

Deuteromycetes Signup and view all the answers

Which fungal disease is primarily acquired through inhalation and is associated with geographical regions?

Systemic mycoses Signup and view all the answers

Which type of nucleic acid is found in dsRNA viruses?

Double-stranded RNA Signup and view all the answers

What type of mycosis is characterized by localized lesions and tends to occur due to wound puncture?

Subcutaneous mycosis Signup and view all the answers

What characteristic is shared by most RNA viruses?

They are single-stranded. Signup and view all the answers

Which organism is commonly associated with causing oral thrush?

Candida spp. Signup and view all the answers

What type of fungi includes mushrooms and is known for producing basidiospores?

Basidiomycetes Signup and view all the answers

Which group in the Baltimore classification corresponds to ssRNA viruses that have a DNA intermediate?

Group VI Signup and view all the answers

What type of symmetry do helically structured viruses exhibit?

Helical Signup and view all the answers

Which of the following represents a primary characteristic of opportunistic mycoses?

They primarily affect immunosuppressed patients. Signup and view all the answers

Which fungus is responsible for causing tinea versicolor?

Malassezia furfur Signup and view all the answers

Which of the following is a characteristic of Poxviridae?

Replication occurs in the cytoplasm. Signup and view all the answers

Which of the following DNA viruses is recognized as a naked virus?

Parvovirus Signup and view all the answers

What is the primary characteristic of viruses regarding their classification as microorganisms?

Viruses possess a nucleocapsid. Signup and view all the answers

Which type of parasitic helminth does NOT belong to platyhelminths?

Nematodes Signup and view all the answers

What is the primary structural characteristic of icosahedral viruses?

Spherical shape with 20 triangular faces Signup and view all the answers

Study Notes

Microorganisms

Microorganisms are classified into several types: bacteria, archaea, protozoa, algae, fungi, viruses, and multicellular animal parasites (helminths).
Each type is characterized by cellular composition, morphology, locomotion, and reproduction.

Bacteria

Bacteria are unicellular prokaryotic organisms (lack a nucleus).
They reproduce by binary fission.
Bacteria can be classified by cell wall stain, response to oxygen (aerobic, anaerobic, facultative anaerobes, microaerobes, capnophilic), and energy source (autotrophs, heterotrophs).
Bacteria exist in four major shapes: Bacillus (rod-shaped), Coccus (spherical), Spirilla (spiral), and Curved (comma-shaped). Examples of bacteria in these shapes include Staphylococcus aureus (Bacillus), Escherichia coli (Coccus), treponema pallidum (Spirilla), and Vibrio cholerae (Curved).

Archaea

Archaea differ from true bacteria in their cell wall structure, lacking peptidoglycans.
They have an affinity for extreme environmental conditions.
Archaea can be classified by habitat (e.g., methanogens thrive in methane-rich environments, halophiles live in salty environments, thermophiles thrive in extremely hot temperatures, and psychrophiles thrive in extremely cold temperatures) and energy source (e.g., phototrophic, chemical energy utilization, or organotrophic). Examples of Archaea include Pyrolobus and Pyrococcus.

Algae

Algae (cyanobacteria) can be unicellular or multicellular eukaryotes.
Algae live in water, damp soil, and rocks.
They reproduce asexually through binary fission, budding, or fragmentation.
Algae produce oxygen and carbohydrates, playing a significant role in atmospheric oxygen production.
Algae are used in circular economy wastewater treatment systems for nutrient removal and biomass production.

Protozoa

Protozoa are unicellular eukaryotes with a nucleus and complex organelles.
They obtain nutrients through absorption or ingestion.
Protozoa are classified based on their locomotion:
Flagellates (e.g., Giardia Lamblia) use whip-like structures for movement.
Ciliates (e.g., Balantidium coli) have tiny hairs that move back and forth.
Amoeboids (e.g., Entamoeba histolytica) move by pseudopodia.
Sporozoans (e.g., Plasmodium falciparum) are nonmotile.

Fungi

Fungi are eukaryotic organisms that lack chlorophyll and do not photosynthesize.
They are either microscopic (molds and yeasts) or macroscopic (mushrooms).
Some fungi are dimorphic (existing as yeast or mold).
Fungi consist of thread-like tubular structures called hyphae. Hyphae grow by tip extension and may be coenocytic or septate, forming clumps of mycelia. Aerial hyphae and vegetative hyphae are associated with fungi.
Cell walls are composed of chitin, and cell membranes contain ergosterol instead of cholesterol.
Fungi are heterotrophic, obtaining nutrients from organic materials through decomposition, symbiotic relationships with plants (symbionts), or harmful relationships with hosts (parasites).
Spores are the reproductive bodies of molds, both sexually and asexually.
Yeasts are unicellular and reproduce by budding; daughter cells can elongate to form pseudohyphae.
Fungi are classified based on sexual reproductive methods (e.g., Zygomycetes, Ascomycetes, Basidiomycetes) or by the absence of known sexual reproduction (e.g., Deuteromycetes). Specific types and examples of fungi are detailed in the original text.
Diseases (mycoses), such as systemic, subcutaneous, cutaneous, and superficial forms, are mentioned, and specific causative agents are highlighted.
Fungi can produce mycotoxins, such as those from Amanita mushrooms or Aspergillus flavus.

Viruses

Viruses are noncellular entities.
Their genomes consist of either DNA or RNA, enclosed in a capsid (protein coat).
Viruses are classified based on nucleic acid (DNA/RNA, double/single-stranded, linear/circular, positive/negative sense RNA), capsid (icosahedral, helical), and presence/absence of an envelope.
Viruses are classified using the Baltimore classification system, which groups viruses by their genome structure and replication method.
DNA viruses (HHAPPPY) are presented in the text.
Most RNA viruses are single-stranded RNA genomes that use a positive or negative sense and have helical symmetry, often enveloped, and replicate in the cytoplasm.
Characteristics of DNA/RNA viruses based on type (e.g., envelopes, structures, replication locations) are noted in the text.

Multicellular Eukaryotic Parasites

Major groups of parasitic helminths (worms) include platyhelminths (flatworms, e.g., cestodes, trematodes), and nematodes (roundworms).
Although not microorganisms, they can have a microscopic stage in their life cycle and are clinically important.
Different types of nematodes, cestodes, and trematodes are presented in the provided text. Characteristics (e.g., life cycle stages, body shapes, reproductive modes) are detailed for each group.

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Description

Explore the fascinating world of microorganisms in this quiz. You'll learn about the classification of various types such as bacteria, archaea, and more, along with their unique characteristics. Test your knowledge on bacterial shapes and reproduction methods.