Amino acids usually exist in the form of Zwitter ions. This mean that they consist of

Options

A. basic-`NH_(2)` group and acidic -COOH group
B. the basic -`overset(+)(N)H_(3)` group and acidic `-C"OO"^(-)` group
C. basic `-NH_(2)` and acidic `-H^(+)` group
D. basic `-COO^(-)` group and acidic -`overset(+)(N)H_(3)` groups

Explanation

To solve the question regarding the zwitterionic form of amino acids, we can follow these steps:

### Step 1: Understand the Structure of Amino Acids
Amino acids are organic compounds that contain both an amine group (-NH2) and a carboxylic acid group (-COOH). The general structure of an amino acid can be represented as:
- A central carbon atom (C)
- An amine group (-NH2)
- A carboxylic acid group (-COOH)
- A hydrogen atom (H)
- A variable side chain (R group)

### Step 2: Formation of Zwitterions
When an amino acid is in a solution, it can undergo a proton transfer. The carboxylic acid group can donate a proton (H+) to the amine group. This results in the formation of a zwitterion, which is a dipolar ion that has both positive and negative charges.

### Step 3: Structure of the Zwitterion
In the zwitterionic form:
- The amine group becomes positively charged (-NH3+).
- The carboxylic acid group becomes negatively charged (-COO-).

Thus, the zwitterionic form of an amino acid can be represented as:
- NH3+ (positively charged amine group)
- CH (central carbon)
- COO- (negatively charged carboxylate group)
- R (side chain)

### Step 4: Conclusion
From the zwitterionic structure, we can conclude that amino acids consist of:
- A basic group (the carboxylate group, COO-)
- An acidic group (the ammonium group, NH3+)

Therefore, the correct answer to the question is that amino acids usually exist in the form of zwitterions, which means they consist of both basic COO- and acidic NH3+ groups.