Viruses
GENERAL DESCRIPTION
- small, non-living particles, no cytoplasm
- consist of genetic material surrounded by a capsid (protein)
- cannot grow/reproduce on their own, do not produce/use energy, do not create waste
- genetic material: DNA/RNA (instructions for synthesizing protein molecules)
- all are infectious: enter a host cell, the viral DNA/RNA controls the cell → cell makes copies of virus
IMPORTANCE
1) Why important?
- human diseases
- high spreading speed, abundant
- Epidemic: large, rapidly spreading outbreak of disease in a limited geographic region
- Pandemic: epidemic that occurs over a widespread geographic area (globally)
- can lead to cancer: infect host cells → create changes in host’s DNA → cancer
- ex: hepatitis C virus → liver cancer
- ecosystems: causing disease → population control
2) A few human diseases caused by viruses.
- common cold, chicken pox (mild)
- AIDS, cholera, rabies (serious)
DNA Virus Hepadnavirus Herpesvirus Adenovirus
Disease hepatitis B cold sores, genital respiratory infections,
herpes, chicken pox tumours
RNA Virus Paramyxovirus Retrovirus Rhabdovirus
Disease measles, mumps, HIV/AIDS rabies
pneumonia, polio,
common cold
GENERAL DESCRIPTION
- small, non-living particles, no cytoplasm
- consist of genetic material surrounded by a capsid (protein)
- cannot grow/reproduce on their own, do not produce/use energy, do not create waste
- genetic material: DNA/RNA (instructions for synthesizing protein molecules)
- all are infectious: enter a host cell, the viral DNA/RNA controls the cell → cell makes copies of virus
IMPORTANCE
1) Why important?
- human diseases
- high spreading speed, abundant
- Epidemic: large, rapidly spreading outbreak of disease in a limited geographic region
- Pandemic: epidemic that occurs over a widespread geographic area (globally)
- can lead to cancer: infect host cells → create changes in host’s DNA → cancer
- ex: hepatitis C virus → liver cancer
- ecosystems: causing disease → population control
2) A few human diseases caused by viruses.
- common cold, chicken pox (mild)
- AIDS, cholera, rabies (serious)
DNA Virus Hepadnavirus Herpesvirus Adenovirus
Disease hepatitis B cold sores, genital respiratory infections,
herpes, chicken pox tumours
RNA Virus Paramyxovirus Retrovirus Rhabdovirus
Disease measles, mumps, HIV/AIDS rabies
pneumonia, polio,
common cold
