The 'Widal test' is a diagnostic test used to detect the presence of antibodies against the causative agent of: MCQ with Answer and Explanation

The 'Widal test' is a diagnostic test used to detect the presence of antibodies against the causative agent of:
A. Dengue
B. Tuberculosis
C. Malaria
D. Typhoid fever
Answer: Option D
Solution (By JKSSB Mock Tests)
The Widal test is a serological agglutination test used to diagnose enteric (typhoid) fever, caused by Salmonella enterica serotype Typhi. It detects the presence of specific antibodies (O and H antigens) in the patient's serum against the O (somatic) and H (flagellar) antigens of the Salmonella typhi bacteria. A significant rise in antibody titer indicates an active or recent infection. It is not used for TB (Mantoux test), malaria (blood smear), or dengue (NS1/IgM).

Discuss this Question (0)

No comments yet. Be the first to start the discussion!

Practice More Biology Questions

Question #1
Which of the following hormones is responsible for the closure of stomata during water stress?
A. Gibberellin
B. Cytokinin
C. Auxin
D. Abscisic acid (ABA)

Correct Answer: Option D


Explanation:
Abscisic acid (ABA) is a stress hormone that induces stomatal closure by causing efflux of K⁺ ions from guard cells, leading to loss of turgor, thereby reducing water loss during drought. Auxin and cytokinin promote growth, gibberellin stimulates stem elongation and seed germination. ABA also promotes seed dormancy and leaf senescence.

This question belongs to: Science Biology
Question #2
The Hardy-Weinberg equation p^2 + 2pq + q^2 = 1 is used to calculate:
A. The carrying capacity of an ecosystem
B. The rate of mutation in a population
C. The energy transfer between trophic levels
D. The expected genotype frequencies in a population

Correct Answer: Option D


Explanation:
The Hardy-Weinberg equation is a fundamental principle in population genetics used to calculate the expected frequencies of genotypes in a population that is not evolving (in genetic equilibrium). 'p' represents the frequency of the dominant allele, and 'q' represents the frequency of the recessive allele. p^2 is the frequency of the homozygous dominant genotype, 2pq is the heterozygous genotype, and q^2 is the homozygous recessive genotype.

This question belongs to: Science Biology
Question #3
Consider statements about human nutrition: 1. Proteins are made of amino acids. 2. Carbohydrates are made of fatty acids. 3. Fats are made of glycerol and fatty acids. Which are correct?
A. 1, 2 and 3
B. 1 and 2 only
C. 1 and 3 only
D. 2 and 3 only

Correct Answer: Option C


Explanation:
Proteins are complex macromolecules composed of long chains of amino acids linked by peptide bonds. Fats (triglycerides) are lipids composed of one glycerol molecule esterified to three fatty acid chains. Carbohydrates are composed of simple sugars (monosaccharides) like glucose, not fatty acids. Thus, statements 1 and 3 are correct, while statement 2 is false.

This question belongs to: Science Biology