Consider statements about human hormones: 1. Insulin lowers blood sugar. 2. Adrenaline prepares the body for stress. 3. Thyroxine requires iodine for synthesis. Which are correct? MCQ with Answer and Explanation
Consider statements about human hormones: 1. Insulin lowers blood sugar. 2. Adrenaline prepares the body for stress. 3. Thyroxine requires iodine for synthesis. Which are correct?
A. 1 and 2 only
B. 1 and 3 only
C. 1, 2 and 3
D. 2 and 3 only
Answer: Option C
Solution (By JKSSB Mock Tests)
Insulin, secreted by the pancreas, promotes cellular glucose uptake, lowering blood sugar levels. Adrenaline (epinephrine) from the adrenal medulla triggers the fight-or-flight response, increasing heart rate and energy supply. Thyroxine, produced by the thyroid gland, requires iodine as an essential component for its synthesis; iodine deficiency causes goiter. All statements are correct.
Explanation:
Vitamin A (Retinol) is essential for the formation of rhodopsin (visual purple), a pigment in the rod cells of the retina necessary for vision in low light conditions. Deficiency of Vitamin A leads to night blindness (nyctalopia), where a person has difficulty seeing in dim light. Severe deficiency can also cause xerophthalmia and complete blindness.
Explanation:
Mendel's first law (law of segregation) states that two alleles of a gene separate during gamete formation (meiosis) so that each gamete receives only one allele. This is due to the separation of homologous chromosomes in anaphase I of meiosis. Fertilization restores the diploid number. This law explains the 3:1 phenotypic ratio in monohybrid crosses. Mitosis maintains the allele pair.
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