Make sure that you know what these terms mean. You will need to use them in context to answer questions on your test.
Virus:
Classification:
● Capsid ● Taxonomy
● Genetic Information (DNA/RNA) ● Binomial Nomenclature
● Tail ● Dichotomous Key
● Tail Fibers ● Surface Markers (glycoproteins) ● Vaccine ● Antibiotic ● Lytic Cycle ● Lysogenic Cycle ● Pathogen ● Host cell
Concepts - Define or provide the answer to these concepts:
1. What is the difference between a lytic and a lysogenic virus?
2. What are some examples of both types of viruses?
3. Why are antibiotics NOT used to cure a virus? What is used to prevent viral infections?
4. Which characteristics of life do viruses have?
5. Label the structures.
Kingdoms:
● Prokaryote
● Eukaryote
● Autotroph
● Heterotroph
● Asexual Reproduction
● Sexual Reproduction
● Multicellular
● Unicellular
1. The lytic cycle is a reproductive cycle of viruses in which the virus enters the host cell, replicates its genetic material, assembles new virus particles, and then lyses (breaks open) the host cell to release the newly formed viruses. The lysogenic cycle is a reproductive cycle of viruses in which the virus inserts its genetic material into the host cell's DNA and becomes dormant, replicating along with the host cell's DNA without causing immediate harm.
2. Examples of lytic viruses include the influenza virus and the common cold virus. Examples of lysogenic viruses include the herpes virus and the HIV virus.
3. Antibiotics are not effective against viruses because antibiotics can only target and kill bacteria, not viruses. To prevent viral infections, vaccines are used. Vaccines stimulate the immune system to produce antibodies that can recognize and destroy specific viruses, providing immunity against future infections.
4. Viruses do not exhibit characteristics of life. They do not have cellular structure, cannot replicate on their own, and do not carry out metabolic processes. However, viruses can possess genetic material, evolve, and reproduce inside host cells.
5. Label the structures:
- Capsid: the protein coat of a virus.
- Genetic Information (DNA/RNA): the genetic material of a virus, either DNA or RNA.
- Tail: the structure of some viruses that helps attach to host cells.
- Tail Fibers: extensions of the tail that aid in host cell attachment.
- Surface Markers (glycoproteins): protein markers on the surface of the virus that help in recognition and attachment to host cells.
- Vaccine: a substance that stimulates the immune system to produce an immune response against a specific virus.
- Antibiotic: a substance that kills or inhibits the growth of bacteria, but not viruses.
- Pathogen: a disease-causing agent, such as a virus.
- Host cell: a living cell that a virus uses to replicate and multiply.
1. The difference between a lytic and a lysogenic virus is in their replication process. In the lytic cycle, the virus attaches to a host cell, injects its genetic material, takes over the cell's machinery to produce more viral components, and eventually causes the cell to burst (lyse), releasing new viruses. In the lysogenic cycle, the virus integrates its genetic material into the host cell's DNA, becoming dormant and replicating along with the host's DNA until it is triggered to enter the lytic cycle.
2. Examples of lytic viruses include the flu virus, HIV, and the common cold virus. Examples of lysogenic viruses include the herpes simplex virus and the varicella-zoster virus (causing chickenpox and shingles).
3. Antibiotics are not effective against viruses because antibiotics target and interfere with specific cellular processes that are unique to bacteria, such as cell wall synthesis or protein synthesis. Since viruses do not have these specific structures or mechanisms, antibiotics cannot effectively target them. To prevent viral infections, vaccines are used. Vaccines stimulate the immune system to recognize and respond to specific viral antigens, providing protection against future infections.
4. Viruses possess some characteristics of life, such as the ability to evolve and adapt to their environment. They also carry genetic material (either DNA or RNA) and can reproduce, although they require a host cell to do so. However, viruses do not display other characteristics of life, such as metabolism or cellular organization. They are considered to be obligate intracellular parasites.
5. Label the structures:
a. Capsid - The protein coat that surrounds the genetic material of a virus.
b. Tail - A structure found in certain bacteriophages that aids in attaching to the host cell.
c. Tail Fibers - Hair-like structures that extend from the tail of a bacteriophage, helping it to recognize and bind to specific host cells.
d. Genetic Information (DNA/RNA) - The genetic material of the virus, either DNA or RNA, which carries the instructions for viral replication.
e. Surface Markers (glycoproteins) - Proteins on the surface of the virus that help it attach to specific receptor sites on host cells.
f. Vaccine - A substance that stimulates the immune system to produce a specific response against a particular virus, providing immunity.
g. Antibiotic - Medication that inhibits the growth or kills bacteria, but is not effective against viruses.
h. Pathogen - A microorganism or agent that can cause disease in a host organism.
i. Host cell - The cell that a virus infects and uses as a host to replicate itself.
To answer these questions, it is important to understand the definitions and concepts related to viruses and the classification of living organisms. Here's how you can find the answers:
1. The difference between a lytic and a lysogenic virus:
- A lytic virus immediately starts multiplying and destroying the host cell, leading to cell death and the release of new virus particles.
- A lysogenic virus incorporates its genetic material into the host cell's DNA without causing immediate harm. The viral genetic material is replicated each time the host cell divides, and it can enter the lytic cycle at a later stage.
To answer this question, you need to explain the definitions of lytic and lysogenic cycles using your own words and provide examples and illustrations if necessary.
2. Examples of both types of viruses:
- Lytic viruses: Influenza, measles, herpes simplex.
- Lysogenic viruses: HIV, hepatitis B virus, human papillomavirus (HPV).
To answer this question, you can research examples of well-known lytic and lysogenic viruses or refer to your textbook or class notes.
3. Why antibiotics are not used to cure a virus and what is used to prevent viral infections:
- Antibiotics are ineffective against viruses because they target bacterial structures or processes. Viruses use host cells to replicate, so there are limited targets for antibiotics.
- To prevent viral infections, vaccines are primarily used. Vaccines stimulate the immune system to recognize and destroy specific viruses or viral components.
To answer this question, you need to understand the mechanism of action of antibiotics and vaccines. You can refer to reliable sources or consult your textbook and class materials.
4. Characteristics of life exhibited by viruses:
- Viruses possess genetic material (DNA or RNA).
- Viruses can reproduce and multiply, but only within host cells.
- Viruses can evolve and adapt.
- However, viruses do not have cellular organization, metabolism, or the ability to respond to stimuli, which are characteristics exhibited by living organisms.
To answer this question, you can explain the characteristics of life and relate them to the specific characteristics of viruses.
5. Labeling the structures of kingdoms and concepts:
- Labeling the structures of kingdoms (e.g., prokaryote, eukaryote, autotroph, heterotroph, asexual reproduction, sexual reproduction, multicellular, unicellular) requires visual representation or illustrations. It is not possible to provide a verbal explanation for labeling.
To answer this question, you can create or refer to diagrams or illustrations that represent each structure or concept.