Question

Which of the following statements about peptide bonds are true? 1) A tetrapeptide contains five amino acid residues. 2) Peptide bonds form from nucleophilic attack by an electron pair on an alpha - amino nitrogen atom on an alpha - carboxyl carbon atom of another amino acid. 3) Peptide bonds are ester linkages. 4) Peptides are polymers of amino acids. 5) Peptide bond formation is a hydrolysis reaction

Answer 1

The correct answers are:

2) Peptide bonds form from nucleophilic attack by an electron pair on an alpha - amino nitrogen atom on an alpha - carboxyl carbon atom of another amino acid and

4) Peptides are polymers of amino acids.

A peptide bond is an amide type of covalent chemical bond. It is formed between two amino acids:  C1 (carbon end) of one alpha-amino acid and N2 (nitrogen end) of another. Peptide bonds are the basis for the formation of a peptide chain and consequently protein.  Formation of peptide bond is a condensation process, meaning that when two amino acids combine and link, water molecule is released and dipeptide is a product of that reaction.

Answer 2

The statement that is true about peptide bonds is;

"Peptide bonds form from nucleophilic attack by an electron pair on an alpha-amino nitrogen atom on an alpha-carboxyl carbon atom of another amino acid."

Further Explanation:  

Amino acids  

• Amino acids act as a building blocks of proteins. They are made up of an amide group (NH2) and a carboxyl group (COOH).
• There are 21 amino acids present in proteins and are classified as either essential or non-essential.
• Essential amino acids are those that are obtained from the diet as humans can not synthesis them. Non-essential amino acids on the other hand are those that can be synthesized in the body.

Proteins  

• Proteins are among the four macro-molecules in living organisms others being; lipids, carbohydrates, and nucleic acids.

• Many amino acids join together through peptide bonds to form polypeptide chains that join to form proteins.

Peptide bonds  

• Peptide bonds are type of amide linkages that join amino acids together to form polypeptides or proteins.
• Each amino acid in a protein is joined to another by a peptide bond.

• During the formation of a peptide bond a carboxyl group of one amino acid combine with an amino group of another amino acid and a molecule of water is released.
• A nucleophilic attack by an electron pair on an alpha-amino nitrogen atom on an alpha-carboxyl carbon atom of another amino acid results to the formation of a peptide bond between two amino acid.

• Therefore, peptide bond formation is an example of a dehydration reaction due to the release of water molecules.

Keywords; Proteins, amino acids, peptide bonds  

Learn more about:

• Macromolecules: brainly.com/question/7173579
• Proteins: brainly.com/question/7173579
• Amino acids: brainly.com/question/2168303
• Peptide bonds: brainly.com/question/708241

Level: High school  

Subject: Biology  

Topic: Macro-molecules  

Sub-topic: Peptide bonds and amino acids