bacterial and viral structure Flashcards
What are bacteria?
Single-celled microorganisms that can be beneficial or harmful.
What are viruses?
Non-living particles that need a host cell to replicate.
What are the main components of a bacterial cell?
Cell wall, plasma membrane, cytoplasm, ribosomes, DNA.
What is the function of the bacterial cell wall?
Provides structural support and protects the cell.
What is the function of the bacterial plasma membrane?
Controls the entry and exit of substances.
What is the role of bacterial ribosomes?
Protein synthesis.
What is bacterial DNA like?
A single circular chromosome located in the nucleoid region.
Do bacteria have organelles?
No, bacteria lack membrane-bound organelles.
What are plasmids in bacteria?
Small, circular pieces of DNA that carry extra genes.
What are pili in bacteria?
Hair-like projections that help bacteria attach to surfaces or transfer DNA.
What is the function of flagella in bacteria?
Helps bacteria move (motility).
What is a capsule in bacteria?
A protective layer outside the cell wall that helps bacteria evade the immune system.
How do bacterial cells divide?
Through binary fission.
What is a virus composed of?
A protein coat (capsid) and genetic material (DNA or RNA).
What is the role of the viral capsid?
Protects the viral genetic material and helps the virus enter host cells.
What are viral envelopes?
Lipid bilayers derived from host cells, covering some viruses.
What types of genetic material do viruses have?
DNA or RNA, but never both.
What is the shape of viral capsids?
They can be helical, icosahedral, or complex.
What is the host range of a virus?
The types of cells or organisms a virus can infect.
What is the difference between enveloped and non-enveloped viruses?
Enveloped viruses have an outer lipid layer; non-enveloped viruses do not.
Can viruses replicate on their own?
No, viruses need a host cell to replicate.
How do viruses enter host cells?
By binding to specific receptors on the host cell’s surface.
What is a bacteriophage?
A virus that infects bacteria.
How do bacterial and viral DNA differ?
Bacterial DNA is circular and in the cytoplasm; viral DNA/RNA can be single or double-stranded.
What is the difference between a lytic and lysogenic cycle in viruses?
Lytic cycle causes the host cell to burst, while lysogenic cycle integrates viral DNA into host DNA.
What is the function of a viral envelope?
Helps the virus enter and exit host cells, providing protection.
What is the difference between DNA and RNA viruses?
DNA viruses use DNA to replicate; RNA viruses use RNA.
Can bacteria be infected by viruses?
Yes, bacteria can be infected by bacteriophages (viruses).
What is an example of a bacterial disease caused by a specific structure?
Pneumonia caused by the capsule of Streptococcus pneumoniae.
What is the function of a virus’s genetic material?
It carries the instructions for replicating the virus inside a host cell.
