Question

which statement is true? (1 point)
the human body uses 20 amino acids to form all types of proteins.
amino acids form a polypeptide chain via carbon - carbon bonds.
amino acids do not need to be assembled in a particular order.
trna is attached to specific proteins in the cell’s cytoplasm.

Explanation:

• Option A: The human body does use 20 standard amino acids to synthesize all its proteins. This is a fundamental biological fact.
• Option B: Amino acids form a polypeptide chain via peptide bonds (between the amino group of one amino acid and the carboxyl group of another), not carbon - carbon bonds.
• Option C: Amino acids must be assembled in a particular order. The order of amino acids in a polypeptide chain is crucial for the protein's structure and function, as it is determined by the genetic code.
• Option D: tRNA (transfer RNA) is attached to specific amino acids (not proteins) in the cell's cytoplasm. tRNA helps in transporting amino acids to the ribosome during protein synthesis.

Answer:

A. The human body uses 20 amino acids to form all types of proteins.