Question

Which type of bond joins the COOH group of one molecule to the NH2 of another molecule? A. 1-4 Glycosidic bond B. Ester bond C. Hydrogen bond D. Peptide bond

Answer 1

Answer:

D. Peptide bond

Explanation:

The reaction between one amino acid and another is

$\rm H _{2} NCH(R)-CO-OH + H-NH-CH(R)COOH\\\\\longrightarrow \,\text{H {_2} NCH(R)-} \underbrace{\text{CO-NH}}_{^\text{peptide}_{\text{bond}}}\text{-CH(R)COOH + H _{2} O}$

The bond that joins the two amino acids is called a peptide bond.

A. is wrong. A 1,4-glycosidic bond is formed between two carbohydrate units.

B.  is wrong. An ester bond is the characteristic feature of fats.

C. is wrong. Hydrogen bonds are intermolecular attractive forces among molecules