Concept explainers
(a)
Interpretation:
The structural formula for the amino acid, threonine is to be drawn. The chiral carbon atom in it is to be identified. The four different groups attached to the chiral carbon atom are to be circled.
Concept introduction:
Amino acids are organic compounds which combine sequentially to generate a protein. They are known as the building blocks of the human body. The main elements present in amino acids are carbon, nitrogen and oxygen while the side chains attached to the chiral carbon atom contain other elements.

Answer to Problem 19.4E
The structural formula for the amino acid, threonine is shown below.
The chiral carbon atoms in it are shown below.
The four different groups attached to the chiral carbon atom are circled as shown below.
Explanation of Solution
Amino acids are formed by an
The structure of threonine is given below.
Figure 1
The chiral carbon atoms in it are shown below.
Figure 2
The four different groups attached to the chiral carbon atom are circled as shown below.
Figure 3
The structural formula for the amino acid, threonine is shown in Figure 1. The chiral carbon atoms in it are shown in Figure 2. The four different groups attached to the chiral carbon atom are shown in Figure 3.
(b)
Interpretation:
The structural formula for the amino acid, aspartate is to be drawn. The chiral carbon atom in it is to be identified. The four different groups attached to the chiral carbon atom are to be circled.
Concept introduction:
Amino acids are organic compounds which combine sequentially to generate a protein. They are known as the building blocks of the human body. The main elements present in amino acids are carbon, nitrogen and oxygen while the side chains attached to the chiral carbon atom contain other elements.

Answer to Problem 19.4E
The structural formula for the amino acid, aspartate is shown below.
The chiral carbon atom in it is shown below.
The four different groups attached to the chiral carbon atom are circled as shown below.
Explanation of Solution
Amino acids are formed by an amine and a carboxylic acid attached to a carbon atom with a characteristic side chain. The carboxylic acid in amino acids is usually in an ionic form and therefore, it is known as carboxylate group.
The structure of aspartate is given below.
Figure 4
The chiral carbon atom in it is shown below.
Figure 5
The four different groups attached to the chiral carbon atom are circled as shown below.
Figure 6
The structural formula for the amino acid, aspartate is shown in Figure 4. The chiral carbon atom in it is shown in Figure 5. The four different groups attached to the chiral carbon atom are shown in Figure 6.
(c)
Interpretation:
The structural formula for the amino acid, serine is to be drawn. The chiral carbon atom in it is to be identified. The four different groups attached to the chiral carbon atom are to be circled.
Concept introduction:
Amino acids are organic compounds which combine sequentially to generate a protein. They are known as the building blocks of the human body. The main elements present in amino acids are carbon, nitrogen and oxygen while the side chains attached to the chiral carbon atom contain other elements.

Answer to Problem 19.4E
The structural formula for the amino acid, serine is shown below.
The chiral carbon atom in it is shown below.
The four different groups attached to the chiral carbon atom are circled as shown below.
Explanation of Solution
Amino acids are formed by an amine and a carboxylic acid attached to a carbon atom with a characteristic side chain. The carboxylic acid in amino acids is usually in an ionic form and therefore, it is known as carboxylate group.
The structure of serine is given below.
Figure 7
The chiral carbon atom in it is shown below.
Figure 8
The four different groups attached to the chiral carbon atom are circled as shown below.
Figure 9
The structural formula for the amino acid, serine is shown in Figure 7. The chiral carbon atom in it is shown in Figure 8. The four different groups attached to the chiral carbon atom are shown in Figure 9.
(d)
Interpretation:
The structural formula for the amino acid, phenylalanine is to be drawn. The chiral carbon atom in it is to be identified. The four different groups attached to the chiral carbon atom are to be circled.
Concept introduction:
Amino acids are organic compounds which combine sequentially to generate a protein. They are known as the building blocks of the human body. The main elements present in amino acids are carbon, nitrogen and oxygen while the side chains attached to the chiral carbon atom contain other elements.

Answer to Problem 19.4E
The structural formula for the amino acid, phenylalanine is shown below.
The chiral carbon atom in it is shown below.
The four different groups attached to the chiral carbon atom are circled as shown below.
Explanation of Solution
Amino acids are formed by an amine and a carboxylic acid attached to a carbon atom with a characteristic side chain. The carboxylic acid in amino acids is usually in an ionic form and therefore, it is known as carboxylate group.
The structure of phenylalanine is given below.
Figure 10
The chiral carbon atom in it is shown below.
Figure 11
The four different groups attached to the chiral carbon atom are circled as shown below.
Figure 12
The structural formula for the amino acid, phenylalanine is shown in Figure 10. The chiral carbon atom in it is shown in Figure 11. The four different groups attached to the chiral carbon atom are shown in Figure 12.
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Chapter 19 Solutions
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