Viruses, Fungi, Protozoa, Bacteria Info
Raudah P. Mangbisa
Grade VIII-Nilo
VIRUS
A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea.
Characteristics:
Like living organisms, viruses contain nucleic acids and proteins. Inside living cells, viruses can reproduce, but not by the process of mitosis like most living cells. Viruses lack some characteristics of living organisms. Outside of living cells, viruses are not alive.
Structure/Shape:
A virus structure can be one of the following: icosahedral, enveloped, complex or helical. These viruses appear spherical in shape, but a closer look actually reveals they are icosahedral.
Icosahedral-These viruses appear spherical in shape, but a closer look actually reveals they are icosahedral. The icosahedron is made up of equilateral triangles fused together in a spherical shape. This is the most optimal way of forming a closed shell using identical protein sub-units. The genetic material is fully enclosed inside of the capsid. Viruses with icosahedral structures are released into the environment when the cell dies, breaks down and lyses, thus releasing the virions.
Examples of viruses with an icosahedral structure are the poliovirus, rhinovirus, and adenovirus.
Envelope- This virus structure is a conventional icosahedral or helical structure that is surrounded by a lipid bilayer membrane, meaning the virus is encased or enveloped.
Complex- These virus structures have a combination of icosahedral and helical shape and may have a complex outer wall or head-tail morphology. The head-tail morphology structure is unique to viruses that only infect bacteria and are known as bacteriophages. The head of the virus has an icosahedral shape with a helical shaped tail.
Helical
This virus structure has a capsid with a central cavity or hollow tube that is made by proteins arranged in a circular fashion, creating a disc like shape.
Grade VIII-Nilo
VIRUS
A virus is a small infectious agent that replicates only inside the living cells of other organisms. Viruses can infect all types of life forms, from animals and plants to bacteria and archaea.
Characteristics:
Like living organisms, viruses contain nucleic acids and proteins. Inside living cells, viruses can reproduce, but not by the process of mitosis like most living cells. Viruses lack some characteristics of living organisms. Outside of living cells, viruses are not alive.
Structure/Shape:
A virus structure can be one of the following: icosahedral, enveloped, complex or helical. These viruses appear spherical in shape, but a closer look actually reveals they are icosahedral.
Icosahedral-These viruses appear spherical in shape, but a closer look actually reveals they are icosahedral. The icosahedron is made up of equilateral triangles fused together in a spherical shape. This is the most optimal way of forming a closed shell using identical protein sub-units. The genetic material is fully enclosed inside of the capsid. Viruses with icosahedral structures are released into the environment when the cell dies, breaks down and lyses, thus releasing the virions.
Examples of viruses with an icosahedral structure are the poliovirus, rhinovirus, and adenovirus.
Envelope- This virus structure is a conventional icosahedral or helical structure that is surrounded by a lipid bilayer membrane, meaning the virus is encased or enveloped.
Complex- These virus structures have a combination of icosahedral and helical shape and may have a complex outer wall or head-tail morphology. The head-tail morphology structure is unique to viruses that only infect bacteria and are known as bacteriophages. The head of the virus has an icosahedral shape with a helical shaped tail.
Helical
This virus structure has a capsid with a central cavity or hollow tube that is made by proteins arranged in a circular fashion, creating a disc like shape.