Tag: dna - history and structure

Questions Related to dna - history and structure

Which one of the following pairs is not correctly matched?

  1. Plasmid - small piece of extrachromosomal DNA in bacteria.

  2. Interferon - an enzyme that helps in DNA replication.

  3. Cosmid - a vector for carrying large DNA fragments into host cells.

  4. Myeloma - tumour cells.


Correct Option: B
Explanation:

Interferons (IFNs) are proteins made and released by virally infected host cells in response to the presence of pathogens, such as viruses, bacteria, parasites, or tumor cells to protect the adjacent cells from the infection by interfering the DNA replication of the virus in the host cell. So, the correct answer is option B.

The name of drug used in cancer treatment produced by biotechnology is

  1. Interferon

  2. HGH

  3. TSH

  4. Insulin


Correct Option: A
Explanation:

Interferons are produced by the body cells as a defensive response to viruses. These belong to the group known as cytokines. Type II interferon is secreted only by natural killer cells and T lymphocytes, its main purpose is to signal the immune system to respond to infectious agents or cancerous growth. So, the correct answer is option A.

Interferon is the body's first line of defense against ............... infection

  1. Viral

  2. Bacterial

  3. Protozoan

  4. All of the above


Correct Option: A
Explanation:

Interferons (IFNs) belong to the large class of proteins known as cytokines, molecules used for communication between cells to trigger the protective defences of the immune system that help eradicate pathogens. Interferons are named for their ability to interfere with viral replication by protecting cells from virus infections. 

Therefore, the correct answer is option A.

Interferon is protein that

  1. Inactivates a bacteria

  2. Protects unattacked cells from virus

  3. Prevents bacteria from taking over the cellular machinary

  4. All of the above


Correct Option: B
Explanation:
  • When the immune system is activated due to the viral infection or other immune response the white blood cells in our body produces Interferons (are a group of proteins called cytokines).
  • The name of the interferons comes from their ability to interfere with the production of new virus particles. Interferons do not directly kill viral or cancerous cells; they boost the immune system response and reduce the growth of cancer cells by regulating the activity of several genes that control the secretion of numerous cellular proteins that affect growth.
  • Hence Interferon is the protein that protects unattacked cells from viruses.
  • So, the correct answer is 'Protects unattacked cells from virus'.

Interferons were discovered by

  1. Zinder and Lederberg

  2. Isaac and Lindemann

  3. Temin

  4. Safferman and Morris


Correct Option: B
Explanation:
  • The first interferon was discovered in 1957 by Alick Isaacs and Jean Lindenmann. During their investigation, the two scientists found that virus-infected cells secrete a special protein that causes both infected and noninfected cells to produce other proteins that prevent viruses from replicating. Hence interferons were discovered by Isaac and Lindemann.
  • So, the correct answer is 'Isaac and Lindemann'.

Interferons are

  1. Protein products of macrophages which destroy microbes

  2. Allergens

  3. Antibody molecule

  4. Proteins secreted by virus infected cells which protect non-infected cells from further viral infection


Correct Option: D
Explanation:
  • When the immune system is activated due to the viral infection or other immune response the white blood cells and virus infected cells in our body secretes Interferons (are a group of proteins called cytokines).Interferons suppress the viral multiplication and protect non infected cells from further infection.
  • The name of the interferons comes from their ability to interfere with the production of new virus particles. Interferons do not directly kill viral or cancerous cells; they boost the immune system response and reduce the growth of cancer cells by regulating the activity of several genes that control the secretion of numerous cellular proteins that affect growth.
  • Hence Interferons are proteins secreted by virus-infected cells which protect non-infected cells from further viral infection.
  • So, the correct answer is 'Proteins secreted by virus-infected cells which protect non-infected cells from further viral infection'.

Assertion : Interferons are a type of antibodies produced by body cells infected by bacteria.

Reason : Interferons stimulate inflammation at the site of injury.

  1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion

  2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion

  3. If the assertion is true but the reason is false

  4. If both the assertion and reason are false

  5. If the assertion is false but reason is true


Correct Option: D

Intererons have been used in the treatment of

  1. Ascariasis

  2. Influenza

  3. Filariasis

  4. Giardiasis


Correct Option: B
Explanation:

Interferons (IFNs) are a group of signalling proteins made and released by host cells in response to the presence of several viruses. A virus-infected cell will release interferons causing nearby cells to heighten their anti-viral defences. Interferons are named for their ability to "interfere" with viral replication (multiplication) by protecting cells from virus infections. Hence, interferons are used in the treatment of viral infections such as influenza. Influenza, commonly known as the flu is an infectious disease caused by an influenza virus.

So, the correct answer is 'Influenza'.

Which of the following staement is related to interferon?

  1. It is a  protein released by animal cells

  2. It is released in response to the entry of a virus

  3. It has the property of inhibiting virus replication

  4. All of the above


Correct Option: D
Explanation:

Interferons are a group of proteins called cytokines, produced by animal white blood cells, fibroblasts or T-cells as part of the immune response to a viral infection or other immune trigger. The name of proteins comes from their ability to interfere with the replication of new virus particles.
Interferons do not directly kill viral or cancerous cells. They boost the immune system response and reduce the growth of cancer cells by regulating the action of several genes that control the secretion of numerous cellular proteins that affect the growth.
The virus infected cells secrete a special protein that causes both infected and non infected cells, to produce other proteins that prevent viruses from replicating and protecting the non infected cells.
So the correct option is 'All of the above'.

Identify the odd from the following ;

  1. $\alpha$ - Interferon

  2. oncogenic virus

  3. proto - oncogenes

  4. UV rays


Correct Option: A
Explanation:
  • The oncogenic virus, proto - oncogenes and UV are involved in the cancer formation; when infected or stimulated have the cancer causing ability.
  • Biological response modifiers such as α-interferon activates the
immune system and helps in destroying the tumor.
So, the correct option is 'α-interferon'.