Question

what was marshall nirenberg and heinrich matthaeis contribution to our current understanding of the genetic code?

discovery of codons
discovery and extraction of dna
creation of a model of dna
creation of photo 51

Explanation:

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<reasoning>

Identify the scientists and their key experiment

Marshall Nirenberg and Heinrich Matthaei performed a groundbreaking cell-free protein synthesis experiment in 1961. They used synthetic RNA containing only uracil (poly-U) to produce a polypeptide chain consisting entirely of the amino acid phenylalanine.

Connect the experiment to the genetic code

This experiment cracked the first word of the genetic code, showing that the triplet UUU (a codon) codes for phenylalanine. This work directly led to the deciphering of all 64 codons in the genetic code.

Evaluate the given multiple-choice options

• discovery of codons: This matches their work in deciphering how triplet sequences of nucleotides (codons) correspond to specific amino acids.
• discovery and extraction of DNA: This was achieved earlier by Friedrich Miescher in 1869.
• creation of a model of DNA: This was done by James Watson and Francis Crick in 1953.
• creation of Photo 51: This famous X-ray diffraction image of DNA was captured by Rosalind Franklin in 1952.

Select the correct option

The correct option is the first one, "discovery of codons".
</reasoning>

<answer>
<mcq-correct>discovery of codons</mcq-correct>
<mcq-option>discovery and extraction of DNA</mcq-option>
<mcq-option>creation of a model of DNA</mcq-option>
<mcq-option>creation of Photo 51</mcq-option>
</answer>

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Answer:

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<reasoning>

Identify the scientists and their key experiment

Marshall Nirenberg and Heinrich Matthaei performed a groundbreaking cell-free protein synthesis experiment in 1961. They used synthetic RNA containing only uracil (poly-U) to produce a polypeptide chain consisting entirely of the amino acid phenylalanine.

Connect the experiment to the genetic code

This experiment cracked the first word of the genetic code, showing that the triplet UUU (a codon) codes for phenylalanine. This work directly led to the deciphering of all 64 codons in the genetic code.

Evaluate the given multiple-choice options

• discovery of codons: This matches their work in deciphering how triplet sequences of nucleotides (codons) correspond to specific amino acids.
• discovery and extraction of DNA: This was achieved earlier by Friedrich Miescher in 1869.
• creation of a model of DNA: This was done by James Watson and Francis Crick in 1953.
• creation of Photo 51: This famous X-ray diffraction image of DNA was captured by Rosalind Franklin in 1952.

Select the correct option

The correct option is the first one, "discovery of codons".
</reasoning>

<answer>
<mcq-correct>discovery of codons</mcq-correct>
<mcq-option>discovery and extraction of DNA</mcq-option>
<mcq-option>creation of a model of DNA</mcq-option>
<mcq-option>creation of Photo 51</mcq-option>
</answer>

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