Biology agar plates
Biology Assessment: Influenza
Structure:
Viruses are non-cellular obligate intracellular parasites, requiring a living host cell in order to reproduce. A developed viral particle (virion) lacks the metabolic machinery of cells, containing just a single type of nucleic acid (DNA or RNA) encased in a protein coat or capsid. Viruses can be distinguished by their structure and by the nature of their genetic material (single or double stranded DNA or RNA). Viruses that affect humans are more difficult to study because they require living animals, embryos, or cell cultures in order to replicate. The particular host range of a virus is determined by the virus’s requirements for attaching to the host cell and the availability, within the host, of the cellular factors needed for viral multiplication. In some viruses, the capsid is covered by an envelope, which protects the virus from the host’s nuclease enzymes. Spikes on the envelope provide a binding site for attachment to the host. Influenza virus is an enveloped virus with many glycoprotein spikes. Viruses are larger than prions and many times smaller than bacteria. They range in size from 30 to 300 nm.
Cause:
The causes of the flu are from three types of influenza viruses: A, B and C. Human influenza A and B viruses cause seasonal epidemics of disease almost every winter. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics.
Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus, the hemagglutinin (H) and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes. Influenza A viruses can be further broken down into different strains. Current subtypes of influenza A viruses found in people are influenza A (H1N1) and influenza A (H3N2) viruses. Influenza B viruses are not divided into subtypes, but can be further broken down into different strains. Type A flu viruses are
Structure:
Viruses are non-cellular obligate intracellular parasites, requiring a living host cell in order to reproduce. A developed viral particle (virion) lacks the metabolic machinery of cells, containing just a single type of nucleic acid (DNA or RNA) encased in a protein coat or capsid. Viruses can be distinguished by their structure and by the nature of their genetic material (single or double stranded DNA or RNA). Viruses that affect humans are more difficult to study because they require living animals, embryos, or cell cultures in order to replicate. The particular host range of a virus is determined by the virus’s requirements for attaching to the host cell and the availability, within the host, of the cellular factors needed for viral multiplication. In some viruses, the capsid is covered by an envelope, which protects the virus from the host’s nuclease enzymes. Spikes on the envelope provide a binding site for attachment to the host. Influenza virus is an enveloped virus with many glycoprotein spikes. Viruses are larger than prions and many times smaller than bacteria. They range in size from 30 to 300 nm.
Cause:
The causes of the flu are from three types of influenza viruses: A, B and C. Human influenza A and B viruses cause seasonal epidemics of disease almost every winter. Influenza type C infections cause a mild respiratory illness and are not thought to cause epidemics.
Influenza A viruses are divided into subtypes based on two proteins on the surface of the virus, the hemagglutinin (H) and the neuraminidase (N). There are 18 different hemagglutinin subtypes and 11 different neuraminidase subtypes. Influenza A viruses can be further broken down into different strains. Current subtypes of influenza A viruses found in people are influenza A (H1N1) and influenza A (H3N2) viruses. Influenza B viruses are not divided into subtypes, but can be further broken down into different strains. Type A flu viruses are