Iodized salt is a vital part of our diet as it is essential for the synthesis of
- A.Estrogen
- B.Thyroxin
- C.Insulin
- D.Adrenalin
Correct answer
Explanation
The correct answer is B, Thyroxin. The thyroid gland needs iodine to make thyroxine, so iodized salt keeps this hormone in supply.
Thyroxine (T4) contains four iodine atoms in each molecule, and the thyroid cannot make it without iodine from food. Thyroxine controls the body's basal metabolic rate and is needed for normal growth and brain development. When the diet lacks iodine, the thyroid enlarges in an attempt to make more hormone, producing goitre; in children severe deficiency causes cretinism and stunted mental growth. India therefore made salt iodization the core of its iodine deficiency disorders programme.
A is wrong because estrogen is a steroid hormone made mainly by the ovaries from cholesterol, with no iodine. C is wrong because insulin is a protein hormone of the beta cells of the pancreas. D is wrong because adrenaline is made by the adrenal medulla from the amino acid tyrosine and needs no iodine.
Exam tip: Iodine → thyroxine → metabolism; lack of iodine causes goitre in adults and cretinism in children.
Practice Questions
View allThe instrument used for detecting the presence of electric current in a circuit is
- A.Refractometer
- B.Galvanometer
- C.Viscometer
- D.Diffractometer
Show answer
A galvanometer detects whether a small electric current is flowing in a circuit and shows its direction. A moving-coil galvanometer has a coil placed between the poles of a magnet.
Read the full explanation →Reverberation is a phenomenon associated with a
- A.multiple refraction of sound.
- B.multiple reflection of sound.
- C.single refraction of sound.
- D.single reflection of sound.
Show answer
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Read the full explanation →Which one of the following is NOT a basic property of electric charge ?
- A.Charges can be added
- B.Charge is conserved
- C.Charge on a body is always an integral multiple of an electron or a proton charge
- D.Charges can be created and destroyed in an isolated system
Show answer
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Read the full explanation →Which of the following organelles have their own DNA and ribosomes?
- A.Endoplasmic reticulum and Golgi bodies
- B.Mitochondria and Chloroplast
- C.Endoplasmic reticulum and cytoskeleton
- D.Cell wall and nucleolus
Show answer
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Read the full explanation →Which one of the following statements is NOT correct ?
- A.All proteins are enzymes
- B.Mostly enzymes are proteins
- C.All fats are energy rich compounds
- D.Glucose is a common carbohydrate
Show answer
This statement is false: enzymes are mostly proteins, but most proteins are not enzymes. Proteins do many jobs in the body.
Read the full explanation →