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Amino Acids and Peptide Bonds
Amino acids are organic compounds that act as building blocks of proteins, while a peptide bond joins amino acids together.
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Amino Acids and Peptide Bonds
Proteins are made from smaller units called amino acids.
A general amino acid contains:
an amino group `–NH₂`; a carboxyl group `–COOH`; a hydrogen; a variable side group `R`.
General form:
`H₂N–CH(R)–COOH`
Recommended for Class 9
Amino Acids and Peptide Bonds
Definition
Amino acids are organic compounds that act as building blocks of proteins, while a peptide bond joins amino acids together.
Formula / Key Relation
Two amino acids can join together.
During this reaction:
one loses `OH`
another loses `H`
and water forms.
The new linkage is called a:
peptide bond
`–CO–NH–`
General amino acid:
`H₂N–CH(R)–COOH`
Peptide bond:
`–CO–NH–`
Amino Acids and Peptide Bonds — Advanced
The joining of amino acids is a condensation reaction.
Repeated peptide-bond formation produces polypeptide chains.
The sequence of amino acids determines the primary structure of a protein and strongly influences its final shape and biological function.
Common Mistakes
Common Mistakes
- Mistake
Do not call the bond between amino acids an ionic bond.
- Mistake
It is a covalent peptide bond.
- Mistake
### Sticky Notes
- Mistake
AMINO ACID
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`NH₂`
- Mistake
- Mistake
`COOH`
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R group
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↓
- Mistake
Peptide bond
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`–CO–NH–`
- Mistake
↓
- Mistake
Polypeptide
- Mistake
↓
- Mistake
Protein
Revision Zone
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Amino acids are protein monomers. They join through peptide bonds to form polypeptides and proteins.
Amino acids are the building blocks of proteins. A typical amino acid contains an amino group, a carboxyl group and a variable R group attached to the central carbon. Amino acids join by condensation reactions, forming peptide bonds with the linkage `–CO–NH–`. Repeated joining produces polypeptide chains. The order of amino acids in the chain is important because it influences the structure and function of the final protein.
- Definition
- Amino acids are the building blocks of proteins. A typical amino acid contains an amino group, a carboxyl group and a variable R group attached to the central carbon. Amino acids join by condensation reactions, forming peptide bonds with the linkage `–CO–NH–`. Repeated joining produces polypeptide chains. The order of amino acids in the chain is important because it influences the structure and function of the final protein.
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Practice
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Q1. What are amino acids?
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Q2. Name two important groups in an amino acid
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Q3. What bond joins amino acids?
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Q4. What is its linkage?
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Q5. What is formed from many amino acids?
Exam Practice
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Q1. Define amino acid
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Q2. Draw/write the general amino acid structure
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Q3. Explain formation of a peptide bond
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Q4. Define polypeptide
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Q5. Explain why amino-acid sequence matters
School-standard facts for Matric and Intermediate. Original explanations — not copied from textbooks.