Question

How many of the following statements about Chlorophyll a, b and c compounds are true ?

1. The structural difference between Chlorophyll a and Chlorophyll b is the presence of an extra double bond on Chlorophyll b.
2. The structural difference between Chlorophylla and Chlorophyll c1 is the presence of a long carbon "tail" chain in Chlorophylla.
3. Complicated mathematical equations are required to correct for the actual measured absorbance concentration of Chlorophyll a.
4. The difference between Chlorophyll c1 and Chlorophyll c2 is that there is the presence of an extra double bond in Chlorophyll c2.
5. Mg²⁺ is the metal that coordinates to two negatively charged N atoms in the central ring.

Answer 1

Only two of the statements regarding the chlorophyll compounds are true, specifically the ones concerning the structural difference involving a carbon chain and the presence of a central magnesium ion.

Step-by-step explanation:

Only statements 2 and 5 about chlorophyll compounds are true. The structural difference between Chlorophyll a and Chlorophyll b is not the presence of an extra double bond in Chlorophyll b; rather, it's a change from a methyl group in Chlorophyll a to an aldehyde in Chlorophyll b. Chlorophyll c1 and Chlorophyll a differ in more than just a long carbon chain, as Chlorophyll c1 also lacks the phytol chain present in Chlorophyll a. The mathematical equations to determine the actual measured absorbance concentration of Chlorophyll a are not necessarily complicated and can vary depending on the analysis protocol.

The structural difference between Chlorophyll c1 and c2 does indeed involve an additional double bond, but it's in Chlorophyll c1 not in Chlorophyll c2. The central metal ion is correctly identified as magnesium (Mg²⁺), which coordinates with four nitrogen atoms in the chlorophyll molecule.