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Questions and Answers
What is the primary characteristic of the organism depicted in the micrograph?
What is the primary characteristic of the organism depicted in the micrograph?
What is the most likely explanation for the organism's inability to generate ATP?
What is the most likely explanation for the organism's inability to generate ATP?
What is the characteristic of the organism that is about 200 nm across its largest dimension?
What is the characteristic of the organism that is about 200 nm across its largest dimension?
What is the significance of the filaments observed in the organism?
What is the significance of the filaments observed in the organism?
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Which of the following is a characteristic of bacteria?
Which of the following is a characteristic of bacteria?
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Which entity acts as a template for protein folding to make more copies of itself?
Which entity acts as a template for protein folding to make more copies of itself?
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What is the reason for the organism's requirement for a host cell?
What is the reason for the organism's requirement for a host cell?
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What is a characteristic of single-celled photosynthetic organisms with nuclei and without cell walls?
What is a characteristic of single-celled photosynthetic organisms with nuclei and without cell walls?
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Which statement is true about bacteriophages?
Which statement is true about bacteriophages?
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How do prions cause diseases like mad cow disease?
How do prions cause diseases like mad cow disease?
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What are the three main branches in the phylogenetic tree of life?
What are the three main branches in the phylogenetic tree of life?
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Which characteristic is unique to protozoa and not found in bacteria?
Which characteristic is unique to protozoa and not found in bacteria?
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What is a characteristic of viroids?
What is a characteristic of viroids?
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Which of the following is a characteristic of Archaea?
Which of the following is a characteristic of Archaea?
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In Pasteur's experiment, what happened when the flasks were not exposed to air?
In Pasteur's experiment, what happened when the flasks were not exposed to air?
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Why did Tyndall's experiment differ from Pasteur's?
Why did Tyndall's experiment differ from Pasteur's?
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What is a major difference between prokaryotes and eukaryotes?
What is a major difference between prokaryotes and eukaryotes?
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Which of the following is NOT a characteristic of viroids?
Which of the following is NOT a characteristic of viroids?
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What is a characteristic of bacteriophages?
What is a characteristic of bacteriophages?
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What is the most likely identification of the organism shown in the pictures?
What is the most likely identification of the organism shown in the pictures?
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What is a structure that is 50 nanometers in diameter and composed of protein, RNA, and lipid most likely an example of?
What is a structure that is 50 nanometers in diameter and composed of protein, RNA, and lipid most likely an example of?
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What could Pasteur logically conclude after his swan necked flask experiment?
What could Pasteur logically conclude after his swan necked flask experiment?
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What does it mean when microbes are described as 'diffusion limited'?
What does it mean when microbes are described as 'diffusion limited'?
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What is a characteristic of Archaea?
What is a characteristic of Archaea?
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What is the most likely explanation for the presence of two organisms on a petri dish after inoculation?
What is the most likely explanation for the presence of two organisms on a petri dish after inoculation?
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What mechanism do viroids use to infect and kill plant cells?
What mechanism do viroids use to infect and kill plant cells?
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What is the characteristic of a culture that is growing on a petri dish?
What is the characteristic of a culture that is growing on a petri dish?
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What is the correct classification of the three domains of life?
What is the correct classification of the three domains of life?
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What would indicate that a newly discovered organism cannot be a virus?
What would indicate that a newly discovered organism cannot be a virus?
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How do prions cause infectious diseases?
How do prions cause infectious diseases?
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Study Notes
Organisms and Structures
- Fungal life cycles include two forms, while algal life cycles contain one specific form.
- Unique bacteria thrive in harsh environments; bacteria generally lack an endomembrane system, which contributes to their small size and lack of internal structures.
- Viruses exist as entities that can infect bacteria, such as Escherichia coli, and contain either RNA or DNA but not both.
Size and Composition of Organisms
- New organisms about 200 nm in size containing DNA, RNA, protein, and lipid indicate a virus due to their inability to generate ATP and reliance on a host for replication.
- Organisms measuring 15 micrometers in diameter are likely to be eukaryotic algae, as evidenced by their chemical composition.
Characteristics of Microbes
- Single-celled photosynthetic organisms with nuclei but no cell walls are classified as algae.
- Prions are infectious proteins that misfold native proteins, causing diseases like mad cow disease.
Phylogenetic Classification
- The primary divisions in the "tree" of life consist of Bacteria, Archaea, and Eukaryotes.
- Prokaryotes are considered distinct from eukaryotes because they lack certain cellular structures such as a nucleus and a cytoskeletal framework.
Microbial Infection and Replication
- Viruses that infect bacteria (bacteriophages) feature a protein coat and are not RNA particles, contrary to common misconceptions.
- Viroids are composed of small pieces of RNA without a protective protein coat and can affect plant cells by inhibiting protein synthesis.
Pasteur's Experiment and Microbial Growth
- Pasteur's experiments with swan-necked flasks demonstrated that boiling media destroys microbes, and they do not regrow from air.
- Tyndall's variations in experiment results were linked to not adequately boiling media containing resilient endospores.
Cellular Mechanisms and Growth Limitations
- Microbes are "diffusion limited," meaning they lack a complex intracellular transport system and typically rely on passive diffusion for nutrient transport.
- The presence of NADH in an analyzed organism indicates it cannot be classified as a virus.
Contamination and Culture Analysis
- Observing mixed organisms in a culture suggest contamination, possibly from prokaryotes or the unintentional inclusion of different biological entities.
- Prions propagate by acting as templates to misfold native proteins, causing infectious diseases.
Summary of Key Insights
- The three domains of life are recognized as Archaea, Bacteria, and Eukaryotes, which shapes our understanding of biological diversity and relationships within the tree of life.
- Differentiating characteristics like cell structure, replication mechanisms, and metabolic pathways are essential for identifying and classifying various microorganisms effectively.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of microorganisms, including viruses, viroids, and archaea. This quiz covers the characteristics and features of these microorganisms, as well as cellular structures and processes.
