Explain why viruses are obligate intracellular parasites

Biology Homework

This is Biology homework. I want to solve those questions based on the materials that I will be uploaded for you. Before solve questions, you should take a look about chapters powerpoint and study guides. There are 5 powerpoint and 5 study guides for chapter 11, 16, 17, 18, and 19. The file name of homework is (Assignments+Chapters+16-19+and+11-1). Be sure, to write easy words and easy vocabularies. Also I want to be free plagiarism.

CHAPTER 19: VIRUSES-answers

The Genetics of Viruses

1. List and describe the structural components of viruses.

-RNA or DNA

-Protein caspid

-Membranous envelope (only some viruses have this)

2. Explain why viruses are obligate intracellular parasites.

-Viruses cannot reproduce on their own, therefore they are obligated to enter the cells (or cell) of living organisms to reproduce. Once inside the cell (intracellular), viruses harm the host and are therefore parasitic.

3. What type of cell does a bacteriophage, such as phage (, infect?

Bacterial cells

4. Describe the lytic and lysogenic reproductive cycles using phage ( as an example .

Lytic:

1. phage attaches to a host cell and injects its DNA

2. phage DNA circularizes in host cell

3. certain factors (intracellular or extracellular) will determine whether the lytic cycle or lysogenic cycle is induced

4. When the lytic cycle is induced, new phage DNA and caspid protein is produced using the host machinery and new phages are assembled

5. The host cell lyses, releasing the new phages. New phages go on to infect new bacterial host cells.

Lysogenic:

1. phage attaches to a host cell and injects its DNA

2. phage DNA circularizes in host cell

3. certain factors (intracellular or extracellular) will determine whether the lytic cycle or lysogenic cycle is induced

4. When the lysogenic cycle is induced, the phage DNA integrates into the bacterial chromosome, becoming a prophage

5. The bacterium reproduces normally, copying the prophage and transmitting it to daughter cells

6. Occasionally a prophage exits the bacterial chromosome initiating the lytic cycle.

5. Distinguish between the lytic and lysogenic reproductive cycles, using phage ( as an example.

Lytic: virus enters and destroys host cell

Lysogenic: virus enters and integrates into the host cell DNA, the host is not destroyed.

6. Describe the 8 steps in the reproductive cycle of an enveloped RNA virus.

1. Glycoproteins on viral envelope bind to specific receptors on the host cell(entry

2. Caspid and viral genome enter the cell, caspid digested by host cell enzymes

3. Viral genome serves as template for complementary RNA strands by a viral enzyme

4. New copies of viral RNA genome are made using the complementary strands of RNA by host enzyme

5. Complementary RNA strands also serve as mRNA which is translated into caspid proteins and glycoproteins for the new viral envelopes.

6. Vesicles transport glycoproteins to the plasma membrane of host cell

7. A caspid assembles around viral genome molecule

8. Each new virus buds from the host cell with viral glycoproteins embedded in membrane derived from the host cell.

7. Are viruses living organisms? Why/Why not?

No, viruses are not considered living organisms because they cannot survive without a living host.