Question

how do viruses infect cells? (coloring)
viruses are non - living organisms that can infect the cells of living organisms. viruses are usually specific to the host. for example, the chickenpox virus infects humans, but does not infect dogs. some viruses can jump species, like the swine flu, which originated in pigs and then jumped to human hosts. viruses make a person sick when they get into the cells and make more viruses, which kills the cells. as the virus multiplies, your immune system attempts to find the virus and kill them before they can make more viruses. this is what makes you feel bad and causes symptoms like running nose, fever, and congestion.
viruses have a wide variety of shapes, but most follow the same basic pattern. each has an envelope with proteins. these proteins act like a key where they attach to the host cell. a respiratory virus like the common cold enters the body when you breathe in particles or transfer it from surfaces to your eyes or nose. once inside the body, the virus proteins attach to the cell surface and the cell takes in the virus where it then releases its contents. those contents include dna that will integrate with the host dna and change the cells activities, causing it to make more viruses using the cells own machinery. these newly assembled viruses leave the cell and then infect other cells.

1. label the stages of infection on the image (use the underlined words above).
2. why is it that a virus that infects humans, is not likely to infect a dog or a cat?
3. what eventually stops the spread of the virus in the host?
4. what occurs after dna is released into the host cell?
5. the virus uses the cells machinery to do what?

Explanation:

1. The stages are: virus attaches to cell membrane, virus releases DNA into cell, cell makes virus parts, new viruses are assembled and leave the cell.
2. Viruses are usually specific to certain hosts due to the specificity of viral - host cell protein interactions.
3. The immune system attempts to fight off the virus and stop its spread.
4. The viral DNA integrates with the host DNA and the cell starts using its machinery to make more viruses.
5. The virus uses the cell's machinery to make more viruses.

Answer:

1. Virus attaches to cell membrane; Virus releases DNA into cell; Cell makes virus parts; New viruses are assembled and leave the cell.
2. Viruses are usually host - specific due to protein - interaction specificity.
3. The immune system.
4. Viral DNA integrates with host DNA and the cell makes more viruses.
5. Make more viruses.