Arachid onic acid ha s a carboxyl group attached to an R group. This R group contain:-

Options

A. 16 carbons
B. 15 carbons
C. 20 carbons
D. 19 carbons

Answer

To solve the question regarding the R group of arachidonic acid, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Arachidonic Acid**:
Arachidonic acid is a polyunsaturated fatty acid that contains a carboxyl group (-COOH) at one end of its carbon chain.

2. **Identify the R Group**:
The R group in fatty acids refers to the hydrocarbon chain that is attached to the carboxyl group. In the case of arachidonic acid, this hydrocarbon chain is composed of carbon and hydrogen atoms.

3. **Count the Carbons in the R Group**:
Arachidonic acid specifically has a total of 20 carbon atoms in its structure, including the carbon in the carboxyl group. Therefore, to find the number of carbons in the R group alone, we subtract the one carbon from the carboxyl group.

\[ \text{Total Carbons} - \text{Carboxyl Carbon} = \text{Carbons in R Group} \]
\[ 20 - 1 = 19 \text{ Carbons in the R Group} \]

4. **Conclusion**:
Thus, the R group of arachidonic acid contains 19 carbon atoms.

### Final Answer:
The R group of arachidonic acid contains 19 carbons.

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