Study Guide: Viruses, Prions, and Prokaryotes – Step-by-Step Guidance

Q1. Why are viruses not considered living things?

Background

Topic: Characteristics of Life

This question tests your understanding of what defines a living organism and why viruses do not meet these criteria.

Key Concepts:

• Characteristics of life (e.g., metabolism, cellular structure, reproduction)

• Virus structure and function

Step-by-Step Guidance

1. List the main characteristics that define living things (such as cellular organization, metabolism, growth, response to stimuli, and reproduction).

2. Consider which of these characteristics viruses possess and which they lack.

3. Think about how viruses reproduce and whether they can do so independently.

4. Reflect on whether viruses have cellular structures or metabolic processes.

Try solving on your own before revealing the answer!

Q2. What are the two basic structural parts of a virus? (Draw them as well)

Background

Topic: Virus Structure

This question is about identifying and understanding the main components that make up a virus.

Key Terms:

• Capsid

• Nucleic acid (genome)

Step-by-Step Guidance

1. Recall the basic structure of a virus and what surrounds its genetic material.

2. Identify the protein shell that encases the viral genome.

3. Think about the type of genetic material found inside (DNA or RNA).

4. Consider drawing a simple diagram labeling these two main parts.

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Q3. If you are swimming in a lake with fish that are infected with a virus, why would it be very unlikely that you would get sick?

Background

Topic: Host Specificity of Viruses

This question tests your understanding of how viruses infect specific hosts and why cross-species infection is uncommon.

Key Concepts:

• Host range

• Viral receptors

Step-by-Step Guidance

1. Think about what determines whether a virus can infect a particular organism.

2. Consider the concept of host specificity and how viruses recognize and enter host cells.

3. Reflect on the differences between fish cells and human cells in terms of viral infection.

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Q4. What kinds of nucleic acids can you find in a virus (the genome)?

Background

Topic: Viral Genomes

This question is about the types of genetic material that viruses can have.

Key Terms:

• DNA (deoxyribonucleic acid)

• RNA (ribonucleic acid)

• Single-stranded vs. double-stranded

Step-by-Step Guidance

1. Recall the two main types of nucleic acids found in living organisms.

2. Consider whether viruses can have either type, and if so, in what forms (single or double stranded).

3. Think about examples of viruses with different types of genomes.

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Q5. Describe how a virus infects a host cell (step by step).

Background

Topic: Viral Infection Cycle

This question asks you to outline the general steps a virus takes to infect and replicate within a host cell.

Key Terms:

• Attachment

• Entry

• Replication

• Assembly

• Release

Step-by-Step Guidance

1. Start by identifying how a virus recognizes and attaches to a host cell.

2. Describe how the viral genome enters the host cell.

3. Explain what happens to the viral genome once inside (replication and protein synthesis).

4. Outline how new viral particles are assembled and released from the host cell.

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Q6. What is a prion? Explain as if you are explaining to somebody who has never taken this class.

Background

Topic: Infectious Agents

This question is about understanding what prions are and how they differ from other infectious agents like viruses and bacteria.

Key Terms:

• Protein

• Infectious agent

• No nucleic acid

Step-by-Step Guidance

1. Think about what makes prions unique compared to viruses and bacteria.

2. Consider how prions are composed and what they lack (e.g., DNA or RNA).

3. Explain in simple terms how a prion can cause disease.

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Q7. How do prions work? Include what they do to the host’s normal proteins in your response.

Background

Topic: Prion Mechanism of Action

This question tests your understanding of how prions cause disease at the molecular level.

Key Concepts:

• Protein misfolding

• Chain reaction

Step-by-Step Guidance

1. Recall what a prion is and how it differs from normal proteins.

2. Describe the process by which a prion interacts with normal proteins in the host.

3. Explain the consequences of this interaction for the host's cells and tissues.

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Q8. What are a couple of examples of prion-caused diseases?

Background

Topic: Prion Diseases

This question asks you to recall specific diseases that are caused by prions.

Key Terms:

• Neurodegenerative diseases

• Transmissible spongiform encephalopathies (TSEs)

Step-by-Step Guidance

1. Think about diseases that affect the brain and nervous system and are known to be caused by prions.

2. Recall examples from humans and animals.

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Q9. What are the two domains of prokaryotes, and how do they differ from each other?

Background

Topic: Classification of Life

This question is about the major groups of prokaryotes and their distinguishing features.

Key Terms:

• Bacteria

• Archaea

• Cell wall composition

• Genetic differences

Step-by-Step Guidance

1. Identify the two domains that include all prokaryotic organisms.

2. List at least two differences between these domains (e.g., cell wall structure, habitat, genetic sequences).

3. Consider examples of organisms from each domain.

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Q10. Rank from smallest to largest: prokaryotic cell, virus, eukaryotic cell

Background

Topic: Cell and Virus Size Comparison

This question tests your understanding of the relative sizes of different biological entities.

Key Concepts:

• Micrometer (μm) and nanometer (nm) scales

• Size ranges of viruses, prokaryotes, and eukaryotes

Step-by-Step Guidance

1. Recall the approximate size range for viruses, prokaryotic cells, and eukaryotic cells.

2. Arrange them in order from smallest to largest based on their typical sizes.

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Q11. Be able to describe the shapes and structures of bacteria. Include in your description of bacterial structures, what each structure does.

Background

Topic: Bacterial Morphology and Anatomy

This question is about recognizing bacterial shapes and understanding the function of their cellular structures.

Key Terms:

• Cocci, bacilli, spirilla

• Cell wall, plasma membrane, flagella, pili, capsule, nucleoid, plasmid

Step-by-Step Guidance

1. List the common shapes of bacteria and their names.

2. Identify the main structures found in bacterial cells.

3. Describe the function of each structure (e.g., movement, protection, genetic material).

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Q12. What is the major structure that allows bacteria to move?

Background

Topic: Bacterial Motility

This question is about identifying the structure responsible for bacterial movement.

Key Terms:

• Flagellum (plural: flagella)

Step-by-Step Guidance

1. Recall which bacterial structure is responsible for movement.

2. Think about how this structure works to propel the cell.

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Q13. What is the DNA like in a prokaryote? Include its shape, and what a plasmid is in your answer.

Background

Topic: Prokaryotic Genetics

This question tests your understanding of the organization of genetic material in prokaryotes.

Key Terms:

• Circular chromosome

• Plasmid

• Nucleoid

Step-by-Step Guidance

1. Describe the main chromosome found in prokaryotes (shape and location).

2. Explain what a plasmid is and how it differs from the main chromosome.

3. Consider the role of plasmids in prokaryotic cells.

Try solving on your own before revealing the answer!

Q14. After binary fission, how do the daughter cells compare to the parent?

Background

Topic: Prokaryotic Cell Division

This question is about the outcome of binary fission in prokaryotes.

Key Terms:

• Binary fission

• Genetic identity

Step-by-Step Guidance

1. Recall the process of binary fission and what happens to the DNA during this process.

2. Consider whether the daughter cells are genetically identical to the parent cell.

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Q15. How quickly do bacteria reproduce? (generally speaking)

Background

Topic: Bacterial Growth

This question is about the rate at which bacteria can divide under optimal conditions.

Key Concepts:

• Generation time

• Exponential growth

Step-by-Step Guidance

1. Recall the typical time it takes for a bacterium to divide under ideal conditions.

2. Think about how this rapid division affects bacterial populations.

Try solving on your own before revealing the answer!

Q16. Do bacteria reproduce sexually, or asexually? Explain.

Background

Topic: Bacterial Reproduction

This question tests your understanding of the mode of reproduction in bacteria.

Key Terms:

• Asexual reproduction

• Binary fission

• Genetic variation

Step-by-Step Guidance

1. Identify the main method by which bacteria reproduce.

2. Explain why this method is considered asexual.

3. Consider if bacteria have any mechanisms for genetic exchange.

Try solving on your own before revealing the answer!

Q17. What is the purpose of a sex pilus? How could this relate to antibiotic resistance?

Background

Topic: Bacterial Conjugation and Antibiotic Resistance

This question is about the role of the sex pilus in genetic exchange and its implications for antibiotic resistance.

Key Terms:

• Sex pilus (plural: pili)

• Conjugation

• Plasmid transfer

• Antibiotic resistance genes

Step-by-Step Guidance

1. Describe the function of the sex pilus in bacterial cells.

2. Explain how the sex pilus is involved in the process of conjugation.

3. Consider how this process can spread antibiotic resistance genes among bacteria.

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Q18. Why are bacteria more able to quickly adapt to their environments (evolve) than multicellular organisms?

Background

Topic: Evolution and Adaptation

This question is about the factors that contribute to the rapid evolution of bacteria.

Key Concepts:

• Mutation rate

• Generation time

• Genetic exchange mechanisms

Step-by-Step Guidance

1. Consider how the short generation time of bacteria affects their ability to evolve.

2. Think about the role of mutations and genetic exchange in bacterial populations.

3. Compare these factors to those in multicellular organisms.

Try solving on your own before revealing the answer!

Be able to define: Capsid, Pandemic, All bacterial structures shown in the PowerPoint, Cocci, Bacilli, Plasmid, Binary Fission, Sex Pili (pilus is singular)

Background

Topic: Key Terms and Definitions

This section is about being able to define important vocabulary related to viruses and prokaryotes.

Key Terms:

• Capsid: Protein shell of a virus

• Pandemic: Widespread outbreak of disease

• Cocci: Spherical bacteria

• Bacilli: Rod-shaped bacteria

• Plasmid: Small, circular DNA molecule in bacteria

• Binary Fission: Asexual reproduction in prokaryotes

• Sex Pilus: Structure for DNA transfer during conjugation

Step-by-Step Guidance

1. Write a concise definition for each term in your own words.

2. For bacterial structures, refer to your PowerPoint or textbook for diagrams and functions.

3. Practice matching each term to its definition and function.

Try solving on your own before revealing the answer!