Questions: m APR material: Cellular metabolism and transport across membranes Previous Page Next Page Page 35 of 49 Question 35 (1 point) Listen How is a polypeptide chain synthesized? a) Amino acids are bound together in a long specified sequence. b) MRNA that is bound to an amino acid, such as tyrosine, associates with a ribosomal subunit. c) Ribosomal subunits bind to a long strand of tRNA molecules. d) Nucleotides are bound together in a long specified sequence. Previous Page Next Page Page 35 of 49 9 MacBook Air

The answer is the first one (or A): Amino acids are bound together in a long specified sequence.

Explanation for each option:

a) Amino acids are bound together in a long specified sequence.

• This is the correct answer. During protein synthesis, amino acids are linked together in a specific order dictated by the sequence of codons in the mRNA. This process occurs in the ribosome and results in the formation of a polypeptide chain.

b) MRNA that is bound to an amino acid, such as tyrosine, associates with a ribosomal subunit.

• This is incorrect. mRNA does not bind directly to amino acids. Instead, mRNA provides the template for the sequence of amino acids, and tRNA molecules, each carrying a specific amino acid, bind to the mRNA sequence during translation.

c) Ribosomal subunits bind to a long strand of tRNA molecules.

• This is incorrect. Ribosomal subunits bind to mRNA, not to a long strand of tRNA molecules. tRNA molecules bring amino acids to the ribosome where they are added to the growing polypeptide chain.

d) Nucleotides are bound together in a long specified sequence.

• This is incorrect in the context of polypeptide synthesis. Nucleotides are the building blocks of nucleic acids (DNA and RNA), not polypeptides. The synthesis of a polypeptide involves the linking of amino acids, not nucleotides.

Summary: The synthesis of a polypeptide chain involves the binding of amino acids in a specific sequence as dictated by the mRNA template. Therefore, the correct answer is A: Amino acids are bound together in a long specified sequence.