Microbiology: Bacteria and Viruses Quiz (BMS Learning Outcomes)

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a distinguishing feature of all viruses compared to bacteria?

Ability to reproduce independently

Encased in a protein shell called a capsid (correct)

Single circular DNA chromosome

Presence of membrane-bound organelles

Which type of virus is HIV classified as based on its nucleic acid?

Single-stranded DNA

Double-stranded RNA

Single-stranded RNA (correct)

Double-stranded DNA

Which of the following is NOT a feature of bacteria?

Presence of chlorophyll (correct)

Ancient life form

Lack of membrane-bound organelles

Single circular DNA chromosome

What type of symmetry does the influenza virus exhibit?

Filamentous or spherical Signup and view all the answers

What is the primary tropism of the Hepatitis B virus?

Liver cells Signup and view all the answers

Which virus is characterized by its ability to mutate more rapidly?

RNA viruses Signup and view all the answers

Which of the following viruses causes cold sores?

Herpes Simplex Virus (HSV-1) Signup and view all the answers

What is the classification of Varicella Zoster Virus based on its nucleic acid?

Double-stranded DNA Signup and view all the answers

Which type of cell does HIV primarily target?

CD4+ T-cells Signup and view all the answers

Which statement about gram-negative bacteria is true?

They are generally more resistant to antibiotics. Signup and view all the answers

Which virus is primarily associated with the persistence of infections without killing host cells?

Human Immunodeficiency Virus Signup and view all the answers

What best describes viral latency?

Dormant virus that can reactivate under certain conditions Signup and view all the answers

What is the first step in the viral replication cycle?

Adsorption to host cell receptors Signup and view all the answers

Which type of tropism is demonstrated by the Hepatitis B virus?

Tissue Tropism Signup and view all the answers

What is a key feature that distinguishes prions from viruses?

Lack of nucleic acids Signup and view all the answers

Which of the following infections could be caused by a prion?

Creutzfeldt-Jakob Disease Signup and view all the answers

What process describes how new virions are released from an infected host cell?

Lysis or budding Signup and view all the answers

What type of virus is commonly associated with oropharyngeal cancers?

Human Papillomavirus Signup and view all the answers

Viral persistence is characterized by which of the following?

Silent periods without viral replication Signup and view all the answers

What defines the mechanism of adsorption in viral replication?

Virus attaching to specific receptors Signup and view all the answers

Study Notes

Bacterial Features

Bacteria are single-celled microorganisms.
They are ancient life forms.
Basic cellular functions are similar to other living cells.
Lack chlorophyll.
Typically have a single, circular DNA chromosome within the cytoplasm.
Lack membrane-bound organelles.

Gram Staining

Gram staining classifies bacteria into two groups: Gram-positive and Gram-negative.

Viral Structure and Classification

Structure:
- Capsid: Protein coat enclosing the viral genome.
- Viral Genome: DNA or RNA (never both).
- Envelope: Some viruses have a lipid membrane surrounding the capsid.
- Nucleocapsid: Combined capsid and genome.
- Other Viral Proteins: Involved in replication.
Classification:
- Symmetry: Icosahedral, filamentous, or complex.
- Nucleic Acid: DNA (dsDNA or ssDNA) or RNA (ssRNA or dsRNA). RNA viruses mutate more frequently.

Specific Virus Features

HIV:
- Symmetry: Icosahedral.
- Nucleic Acid: ssRNA, retrovirus.
- Tropism: Targets CD4+ T-cells.
Hepatitis B Virus (HBV):
- Symmetry: Icosahedral.
- Nucleic Acid: dsDNA.
- Tropism: Infects liver cells.
Varicella Zoster Virus (VZV):
- Symmetry: Icosahedral.
- Nucleic Acid: dsDNA.
- Tropism: Skin and nerve cells (chickenpox/shingles).
Herpes Simplex Virus (HSV):
- Symmetry: Icosahedral.
- Nucleic Acid: dsDNA.
- Tropism: Skin, mucous membranes, nerve cells (cold sores/genital herpes).
Influenza Virus:
- Symmetry: Filamentous or spherical.
- Nucleic Acid: ssRNA.
- Tropism: Respiratory tract cells.

Dentally Relevant Viruses

Herpes Simplex Virus (HSV-1): Oral herpes (cold sores).
Varicella Zoster Virus (VZV): Chickenpox/shingles (can affect oral tissues).
HIV: Immunocompromised patients susceptible to oral infections (e.g., candidiasis, Kaposi's sarcoma).
Human Papillomavirus (HPV): Linked to oral cancers.
Hepatitis B Virus (HBV): Risk of transmission during dental procedures.

Viral Tropism

Viral tropism: Ability to infect specific cells, tissues, or hosts.
Cellular tropism: Virus infects specific cell types.
Tissue tropism: Virus preference for particular tissues.
Host tropism: Viruses infecting specific species.

Viral Replication

Adsorption: Virus attaches to host cell receptors.
Penetration: Virus enters host cell.
Uncoating/Eclipse Phase: Viral genome is released.
Transcription: Viral genome produces mRNA.
Synthesis of Components: Viral proteins and genomes produced.
Assembly: Viral components assemble into new virions.
Release: Virions released (lysis or budding).

Viral Persistence and Latency

Viral Persistence: Virus presence without immune clearance. Can include productive phases.
Examples: HIV, Epstein-Barr virus, Hepatitis B virus.
Viral Latency: Dormant virus in host cells. Replication triggered by external factors (stress, immunity suppression).
Examples: Herpes Simplex Virus (HSV), Varicella-Zoster Virus (VZV).

Prions

Prions: Infectious misfolded proteins causing other proteins to misfold.
Key Feature: Lack nucleic acids, resistant to denaturation.
Diseases: Neurodegenerative like Creutzfeldt-Jakob Disease (CJD) and Bovine Spongiform Encephalopathy (BSE).
Relevance: Fatal; difficult to sterilize against.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers essential features of bacteria and viruses, including their structural characteristics and classification methods. It highlights the differences between Gram-positive and Gram-negative bacteria, as well as details about viral structures and notable examples like HIV. Test your knowledge on these fundamental microbiological concepts.