Viruses
Understand the structure, genetic material, replication, and diseases caused by viruses, which are acellular entities not fitting into the five kingdoms.
What is Viruses?
The protein shell that encloses the genetic material of a virus.
Key points
- Define a virus and explain why it is not considered living.
- Describe the basic structure of a virus.
- Explain the process of viral replication.
- Identify diseases caused by viruses.
Common exam trap
Considering viruses as living organisms.
Definitions
- Term
Capsid
- Meaning
The protein shell that encloses the genetic material of a virus.
- Term
Capsomere
- Meaning
Subunit of the capsid, a protein molecule.
- Term
Envelope
- Meaning
An outer lipid layer surrounding the capsid of some viruses, derived from the host cell membrane.
- Term
Obligate intracellular parasite
- Meaning
An organism that can only survive and reproduce inside a host cell.
- Term
Bacteriophage
- Meaning
A virus that infects and replicates within bacteria.
- Term
Viroid
- Meaning
An infectious agent that consists only of a strand of RNA, with no associated proteins.
- Term
Prion
- Meaning
An infectious agent composed of misfolded protein, without any genetic material.
Learning objectives
Define a virus and explain why it is not considered living.
Describe the basic structure of a virus.
Explain the process of viral replication.
Identify diseases caused by viruses.
Differentiate between viruses, viroids, and prions.
Prerequisites
Basic understanding of cell structure and function.
Knowledge of genetic material (DNA and RNA).
Familiarity with basic biological terms like 'parasite' and 'host'.
Common mistakes
Considering viruses as living organisms.
Confusing viruses with bacteria.
Forgetting that viruses can have either DNA or RNA, but not both.
Not understanding the obligate parasitic nature of viruses.
Keywords
Virus
Acellular
Obligate Parasite
Capsid
Genetic Material
Replication
Bacteriophage
Viroid
Prion
Infectious Disease
Practice preview
Which of the following is a disease caused by a virus?…
easy
The process by which a virus replicates within a host cell, leading to the destruction of the host cell, is known as:…
medium
A virus that infects bacteria is called a:…
medium