All Free Biology MCQs with Answers
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19,844 questions · page 952 of 993
- A. Heavy chain
- B. Light chain
- C. Variable region
- D. Constant region
Explanation: The variable region binds specifically to antigens, giving antibodies their specificity.
Correct answer: Variable region19022. Two identical light chains and two identical heavy chains in the antibody molecule are linked by:
- A. Disulphide bridges
- B. Peptide bond
- C. Glycerol bond
- D. Ionic bond
Explanation: Disulphide bonds can be used to hold different sub-units of protein complexes together, as is found in antibodies between the light chains…
Correct answer: Disulphide bridges- A. Basophils
- B. Platelets
- C. Monocyte
- D. Eosinophils
Explanation: Histamine is synthesized primarily by mast cells, basophils, histaminergic neurons in the basal ganglia of the brain, and…
Correct answer: Basophils- A. Eosinophils
- B. Monocytes
- C. Neutrophils
- D. Lymphocytes
Explanation: Neutrophils are the most abundant WBCs. These are phagocytic. They kill and digest bacteria and fungi.
Correct answer: Neutrophils- A. cell-mediated response
- B. Humoral Response
- C. Active Response
- D. Compound Response
Explanation: Immunity provided by the AB secreted in the circulatory system by B cells is termed humoral immunity.
Correct answer: Humoral Response- A. Both light chains only
- B. Both heavy chains only
- C. One heavy and one light chain
- D. Both heavy and light chains
Explanation: The amino acid sequence in the tips of the "Y" varies greatly among different antibodies.
Correct answer: Both heavy and light chains- A. Basophil
- B. Neutrophil
- C. Eosinophil
- D. Monocyte
Explanation: Basophils release heparin to prevent blood clots and histamine which causes inflammation.
Correct answer: Basophil- A. Eight
- B. Four
- C. Six
- D. Two
Explanation: An Antibody molecule is made up of 4 polypeptide chains i.e. two heavy chains and two light chains. (PTB page:326)
Correct answer: Four- A. Memory cells
- B. B-lymphocytes
- C. T-lymphocytes
- D. Plasma cells
Explanation: Plasma B cells are cells produced or specialized in the bone marrow. They tend to release significant amounts of antibodies in response to…
Correct answer: Plasma cells- A. Active Immunity
- B. Natural active immunity
- C. Passive immunity
- D. Vaccination
Explanation: The method of passive immunization is used to combat active infections such as tetanus, rabies, snake venom, etc. (PTB page:327)
Correct answer: Passive immunity- A. Antibiotics, antigen
- B. Antibodies, RBC
- C. Globulin, histamine
- D. Antibodies, antigen
Explanation: Antibodies, also known as immunoglobulins, are proteins produced by white blood cells in response to antigens, and they play a crucial…
Correct answer: Antibodies, antigen- A. Parallel
- B. Both A, C
- C. Antiparallel
- D. None of these
Explanation: Coiling of two strands is opposite i.e they are coiled antiparallel to each other.
Correct answer: Antiparallel- A. CGAUACC
- B. CGTATGC
- C. CGATACC
- D. CGUTCC
Explanation: ExplanationThe mRNA would be complementary to the given DNA strand. RNA has Uracil Base instead of thymine.
Correct answer: CGAUACC- A. Dehydration
- B. Oxidation
- C. Rehydration
- D. Reduction
Explanation: Explanation:This is a dehydration reaction involving the formation of phosphodiester bonds.This option is incorrect.
Correct answer: Dehydration- A. Restriction endonuclease
- B. DNA helicase
- C. Primase
- D. DNA ligase
Explanation: Explanation:DNA Ligase is an enzyme that catalyzes the formation of a phosphodiester bond between adjacent Okazaki fragments on the…
Correct answer: DNA ligase- A. Uracil
- B. Thymine
- C. Cytosine
- D. Adenine
Explanation: [A] Uracil is a pyramiding present in RNA but not in DNA[B] Thymine(pyrimidine) is present in DNA[C] Cytosine(pyrimidine) is also present…
Correct answer: Uracil- A. Insertion
- B. Transposition
- C. Deletion
- D. Base Substitution
Explanation: In Sickle cell anemia, the gene for beta-globin is mutated. As a result, the amino acid valine is replaced by glutamic acid and the RBC…
Correct answer: Base Substitution- A. Uracil
- B. Thymine
- C. Guanine
- D. Cytosine
Explanation: The given structure is of a pyrimidine base which bears resemblance to the structure of Cytosine.
Correct answer: Cytosine- A. Making proteins.
- B. Making amino acids.
- C. Breakdown of ribose sugar
- D. Carries genetic material.
Explanation: DNA is a hereditary material which carries the genetic information generation after generation.
Correct answer: Carries genetic material.- A. Heterotherms
- B. Endotherms
- C. Ectotherms
- D. None of these
Explanation: Heterotherms are those animals who are capable of varying degrees of endothermic heat production but generally do not regulate their body…
Correct answer: Heterotherms