Question

Which of the following represents the correct molecular formula of chlorophyll $b$ ?

• A. $C _{55} H _{72} O _{6} N _{4} Mg$
• B. $C _{55} H _{72} O _{5} N _{4} Mg$
• C. $C _{55} H _{72} O _{4} N _{4} Mg$
• D. $C _{55} H _{70} O _{6} N _{4} Mg$

Answer 1

Answer: (D)

Chlorophyll is green photosynthetic pigment which occurs in photosynthetic thylakoids of chloroplast and takes part in absorption of light energy for the purpose of photosynthesis. Five types of chlorophylls occur in plants other than bacteria $-a, b, c, d, e$, of which only two chlorophyll i.e. chlorophyll $a$ and $b$ occur in higher plants. Chlorophyll $b$ differs from chlorophyll $a$ in having formyl or aldehyde group (-CHO) instead of methyl group $\left(- CH _{3}\right)$ at carbon atom 3 . The molecular formula of chlorophyll $a$ and $b$ are $C _{55} H _{72} O _{5} N _{4} Mg$ and $C _{55} H _{70} O _{6} N _{4} Mg$ respectively.