viruses

• Viruses are not classified as living things because they are non-cellular and do not carry out any metabolic reactions on their own.
• All viruses have a simple structure consisting of a core of nucleic acid (either DNA or RNA, never both) and a protein coat (capsid) on its surface.
• Viruses are not included in any of the 5 kingdoms because they are non-cellular and do not carry out any metabolic reactions on their own.
• Viruses can be distinguished by their shape of the protein coat, type of nucleic acid, size, structure, and antibody/antigen reaction.
• Living organisms possess genetic material (DNA OR RNA), are cellular, can reproduce by themselves, carry out metabolic reactions on their own, and possess ribosomes and mitochondria.
• Viruses possess genetic material (DNA OR RNA), are non-cellular, cannot reproduce by themselves, cannot carry out metabolic reactions on their own, and do not possess ribosomes and mitochondria.
• Bacteriophage: a virus that infects bacteria.
• Bacteria have defences to counter these, for example, they can produce enzymes called restriction enzymes, which act like genetic scissors and have the ability to cut the viral nucleic acid.
• Retroviruses: contain RNA (instead of DNA) and an enzyme that converts the virus RNA to DNA.
• This DNA then makes copies of the virus RNA.
• The virus HIV that causes Aids is a retrovirus.
• AIDS has no cure or vaccine, prevention is vital in controlling the spread of the disease.
• Prevention of AIDS includes using a condom, not using shared needles/razors/toothbrushes, avoiding contact with blood/bodily fluids and always wearing gloves.
• Viruses can be used as biological controls for pests.
• Viruses damage crops, for example, tomato mosaic virus.
• The resulting host cells may behave normally or may produce new chemicals, due to the presence of virus.
• HIV enters the body in fluids such as blood, semen.
• Beneficial economic effects of viruses include genetic engineering, where viruses are used as vectors to carry genes from the source to the host cell.
• Antibiotics cannot cure viral diseases.
• Viruses cause many human diseases including AIDS (HIV), influenza (‘flu’), hepatitis, measles, and more.
• Control of immunity in AIDS can be achieved through vaccination.
• Some viruses do not destroy the host DNA, instead viral DNA integrates (joins) with the host DNA and remains inactive.
• Viruses can be used in the production of vaccines, such as the MMR vaccine.
• Harmful economic effects of viruses include when people are ill, they cannot work, affecting the economy.
• HIV Virus causes AIDS (Acquired immune deficiency syndrome), a disorder in which a person cannot make antibodies due to infection with HIV (human immunodeficiency virus).
• When host DNA is copied, virus DNA is also copied and passed on to daughter cells.
• viruses can be round< rod or spiral
• order of virus replication: attachment, entry, synthesis, assembly, release
• a virus attaches to a host cell. The viruses nucleic acid enters the host cell. using the host structures , the virus begins to replicate its different parts. Virus assembly occurs and the virus is released.
• a vaccine is a non disease causing dose of a pathogen which stimulates the production of antibodies
• a vaccination is the act of introducing a vaccine into the body