propose structual formulas for pheophytin a and pheophytin b
We can't draw structures on the board but here is what I could find on the web. I don't see any structures but there is a lengthy description. Perhaps you already know all of this; perhaps not. Use it if you can.
http://en.wikipedia.org/wiki/Pheophytin
To propose the structural formulas for pheophytin a and pheophytin b, we need to understand the general structure of chlorophylls and how they differ from one another.
Both pheophytin a and pheophytin b are derived from chlorophylls by removing the central magnesium ion and replacing it with a hydrogen ion. This modification results in the conversion of chlorophylls to pheophytins.
Here are the steps to propose the structural formulas for pheophytin a and pheophytin b:
1. Understand the basic structure of chlorophyll:
- Chlorophylls consist of a porphyrin ring, which is a large ring structure composed of four pyrrole groups linked together.
- The porphyrin ring contains a central magnesium ion, which coordinates with the nitrogen atoms of the pyrrole groups.
- Chlorophylls also have a long hydrocarbon tail known as a phytol chain.
2. Remove the central magnesium ion:
- To convert chlorophylls to pheophytins, the central magnesium ion needs to be removed and replaced with a hydrogen ion (H+).
3. Retain the remaining structure:
- The porphyrin ring structure remains intact after removing the magnesium ion.
- The phytol chain also remains the same.
With this understanding, we can now propose the structural formulas for pheophytin a and pheophytin b:
- Pheophytin a: The structural formula for pheophytin a can be represented as follows:
Pheophytin a:
H
|
C=C
| \
C C
| \
C C
| \
C C
| \
C C
| \
C=CH(CH3)-CH2-CH(CH3)-CH2-CH(CH3)-CH3
- Pheophytin b: The structural formula for pheophytin b is very similar to pheophytin a, with a slight difference in one of the side chains:
Pheophytin b:
H
|
C=C
| \
C C
| \
C C
| \
C C
| \
C CH3
|
C=CH(CH3)-CH2-CH(CH3)-CH3
Please note that the structural formulas provided represent the general structures of pheophytin a and pheophytin b. The actual structures may vary slightly due to specific branching patterns or other modifications in different organisms.