Viruses and Cells

Ireland Beverly PAP Biology, Period 3 Tyrell

Labeled Animal Cell

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Labeled Plant Cell

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The Lytic Cycle

The Lytic Cycle is a fast track cycle a virus goes through. A virus attaches itself to the host cell, enters the cell, takes over the cell and replicates its parts, assembles its parts, and bursts out of the host cell and destroying the host cell. An example of a virus that goes through the Lytic Cycle is the Influenza Virus.
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The Lysogenic Cycle

The Lysogenic Cycle is a slower cycle a virus goes through. The virus attaches and enters the host cell, fuses its DNA with the cells DNA, divides with the cell, activates the virus, and enters the Lytic Cycle. An example of a virus that goes through the Lysogenic Cycle is the HIV Virus.
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The Characteristics of life

Living things:

-grow and develop

-have DNA

-respond to the environment

-are made of cells


-maintain homeostasis

-obtain and use material and energy


-are organized

Viruses are not living things, they do not respond to their environment, are not made of cells, do not maintain homeostasis, grow and develop, obtain and use material and energy, nor are organized. Though some argue they are living things because they have some sort of genetic material, either DNA or RNA, reproduce, although they cannot reproduce on their own, and evolve.

They do not have some of these characteristics because they are very simple, although some are more complex than others, and have very few parts, usually only a protein coat, enzymes, and nucleic acid. They also do not move and do not obtain and use material and energy nor maintain homeostasis nor grow and develop, .

They do however have certain characteristics because they need only the simplest parts to reproduce and infect organism. Also they are able to evolve due to mutations.

Question and Answer

Q: Describe the typical structure of a virus. What is a virus made of? What biomolecules would you find in a virus?

A: They typical structure and what a virus is made of is a nucleic acid, DNA or RNA, enzymes, a protein overcoat around the virus called a capsid, and sometimes a lipid envelope covering the capsid. The biomolecules found are proteins, nucleic acids, and lipids, which are the capsid, DNA or RNA, and lipid envelope.

Q: Discuss the different ways viruses gain entry into a cell.

A: Viruses gain entry in the cell by either using the virus's surface proteins to match with the host cell's structure or by using a process like endocytosis.

Q: Explain why the Ebola virus would not infect a tobacco plant.

A: The Ebola virus would not infect a tobacco plant because viruses are highly specific and are only able to invade a specific cell, so since Ebola infects humans and animals, it would not infect a plant.

Q: Name five viruses and the type of cell that they attack.

A: HIV attacks helper T cells. Influenza, rabies, and the common cold attack animal cells. While the lettuce mosaic virus attacks plant cells.

Q: You have been diagnosed with the flu. Explain why a doctor will not provide you

with a prescription for antibiotics in order to cure your infection.

A: Your doctor would not prescribe antibiotics because the flu is a virus and antibiotics do not work on viruses.

Q: How is it that a person can be infected with a virus such as HIV and not exhibit


A: A person might not have symptoms if infected with a virus such as HIV since it is a retrovirus and it goes through the lysogenic cycle, meaning it could be years before the virus becomes active.