Human chorionic gonadotropin (hCG) is a placental gonadotropin that controls hormonal secretions from corpus luteum during the initial stage of pregnancy. Following statements are made about hCG:

A. It is a glycoprotein that contains galactose and hexosamine.
B. It is a heterodimer with a larger alpha subunit and larger beta subunit.
C. It is a heterodimer with a smaller alpha subunit and larger beta subunit.
D. hCG is identical to beta subunit of LH and FSH.
E. It appears as early as 6 days after conception in blood and 14 days after conception in urine.

Which one of the following has all correct combination of statements?

Correct option is B

Explanation-

Statement A -  It is a glycoprotein that contains galactose and hexosamine - CORRECT
hCG is a glycoprotein hormone composed of carbohydrate groups including galactose and hexosamine, among others (like fucose and sialic acid).
Statement B - It is a heterodimer with a larger alpha subunit and smaller beta subunit  - INCORRECT
hCG is a heterodimer, but the beta subunit is larger than the alpha subunit. The alpha subunit is common to LH, FSH, TSH; the beta subunit is unique to each hormone and gives specificity.
Statement C - It is a heterodimer with a smaller alpha subunit and larger beta subunit- CORRECT
This is accurate. The beta subunit is larger and provides the biological activity and specificity.
​Statement D - hCG is identical to beta subunit of LH and FSH - INCORRECT
​hCG shares an identical alpha subunit with LH, FSH, and TSH. The beta subunit of hCG is similar to LH, but not identical — it has an extended C-terminal peptide. It is not identical to FSH’s beta subunit.
Statement E - It appears as early as 6 days after conception in blood and 14 days after conception in urine  - CORRECT
hCG can be detected in blood ~6–8 days after conception. In urine, it becomes detectable typically by 14 days (the time of a missed period).

Final Answer:
Correct statements: A, C, and E (Option b)