Question

question 4

which of these determines which protein will be built?

the sequence of phosphates
the sequence of nitrogenous bases
the sequences of amino acids
the sequence of deoxyribose sugars

Explanation:

Analyze the question

The question asks what determines which specific protein will be built in a cell.

Evaluate genetic information storage

To build a protein, the cell needs instructions. These instructions are stored in DNA (and transcribed into mRNA). DNA is a polymer of nucleotides, which consist of a phosphate group, a deoxyribose sugar, and a nitrogenous base. The backbone (phosphates and sugars) is identical throughout the molecule, meaning it cannot carry specific genetic instructions.

Identify the variable sequence

Using our understanding of Nucleic Acids, the only variable part of the DNA molecule that can encode information is the sequence of its nitrogenous bases (Adenine, Thymine, Cytosine, and Guanine).

Link genetic code to protein synthesis

The sequence of nitrogenous bases in DNA is transcribed into mRNA codons. Each codon specifies a particular amino acid. Therefore, the sequence of nitrogenous bases determines the sequence of amino acids, which ultimately determines the structure and function of the Proteins being built.

Compare the given options

• "The sequence of phosphates" and "the sequence of deoxyribose sugars" are repetitive and uniform, so they cannot carry genetic information.
• "The sequences of amino acids" is what constitutes the protein itself, but it does not determine (instruct) which protein is built; rather, it is the result of the instructions.
• "the sequence of nitrogenous bases" contains the actual genetic code that determines the amino acid sequence of the protein.

Answer:

• The sequence of phosphates
• the sequence of nitrogenous bases (Correct answer)
• the sequences of amino acids
• the sequence of deoxyribose sugars