An antibody molecule is represented as H₂L₂ because it consists of:

[Human-Health-and-Disease] [class-xii ]

• Two heavy chains and two light chains
• Two primary chains and two secondary chains
• Four heavy chains and two light chains
• Two helper chains and two lipid chains
Correct Option: A  [ Two heavy chains and two light chains ]

Remark: An antibody molecule has two small light chains and two longer heavy chains, represented as H₂L₂.

Which of the following is NOT listed as a type of antibody produced in the human body?

[Human-Health-and-Disease] [class-xii ]

• IgA
• IgM
• IgE
• IgD (not listed in source)
Correct Option: D  [ IgD (not listed in source) ]

Remark: IgA, IgM, IgE, IgG are some of the types mentioned.

The immune response characterized by antibodies found in the blood is called:

[Human-Health-and-Disease] [class-xii ]

• Cell-mediated immune response (CMI)
• Humoral immune response
• Innate immunity
• Cytokine response
Correct Option: B  [ Humoral immune response ]

Remark: Because antibodies are found in the blood, the response is called humoral immune response.

Which type of immune response is mediated by T-lymphocytes and is responsible for graft rejection during organ transplantation?

[Human-Health-and-Disease] [class-xii ]

• Humoral immune response
• Cell-mediated immune response (CMI)
• Passive immunity
• Innate immunity
Correct Option: B  [ Cell-mediated immune response (CMI) ]

Remark: The T-lymphocytes mediate CMI, and this response is responsible for graft rejection.

When a host is exposed to antigens (living or dead microbes) and produces antibodies itself, this is called:

[Human-Health-and-Disease] [class-xii ]

• Passive immunity
• Acquired immunity
• Active immunity
• Auto immunity
Correct Option: C  [ Active immunity ]

Remark: When a host is exposed to antigens, and antibodies are produced in the host body, this is called active immunity.

When ready-made antibodies are directly given to protect the body against foreign agents, it is called:

[Human-Health-and-Disease] [class-xii ]

• Active immunity
• Primary response
• Passive immunity
• Anamnestic response
Correct Option: C  [ Passive immunity ]

Remark: When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.

Which antibody is abundant in colostrum (mother's milk) and provides passive immunity to the newborn infant?

[Human-Health-and-Disease] [class-xii ]

• IgG
• IgM
• IgE
• IgA
Correct Option: D  [ IgA ]

Remark: The yellowish fluid colostrum has abundant antibodies (IgA) to protect the infant, which is passive immunity.

A preparation of antigenic proteins of a pathogen or inactivated/weakened pathogen introduced into the body is called a:

[Human-Health-and-Disease] [class-xii ]

• Antibiotic
• Antitoxin
• Immunosuppressant
• Vaccine
Correct Option: D  [ Vaccine ]

Remark: In vaccination, a preparation of antigenic proteins of pathogen or inactivated/weakened pathogen (vaccine) are introduced into the body.

If a person is infected with deadly microbes requiring a quick immune response, such as in tetanus or snakebites, the injection provided contains:

[Human-Health-and-Disease] [class-xii ]

• A weak pathogen
• Antigenic proteins
• Preformed antibodies or antitoxin
• T-lymphocyte stimulators
Correct Option: C  [ Preformed antibodies or antitoxin ]

Remark: We need to directly inject the preformed antibodies, or antitoxin, which is passive immunisation.

The Hepatitis B vaccine is produced using which advanced biological technique?

[Human-Health-and-Disease] [class-xii ]

• Hybridoma technology
• Recombinant DNA technology
• Classical immunisation
• Widal test
Correct Option: B  [ Recombinant DNA technology ]

Remark: Recombinant DNA technology has allowed the production of vaccines like hepatitis B vaccine produced from yeast.