Question

3 dna, rna, and protein (continued)
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1. summarize the process by which the dna code is made into a protein

1. describe the function of each of the following in protein synthesis: rrna, mrna, and trna

1. explain why scientists concluded that the instructions for species characteristics were carried in dna

1. explain the role of rna polymerase in mrna synthesis.

1. conclude why beadle and tatum’s “one gene, one enzyme” hypothesis has been modified since they presented it in the 1940s.

1. if the genetic code used four bases as a code instead of three, how many code units could be encoded?

Explanation:

1. The process of converting DNA code to protein involves two main steps: transcription (DNA → mRNA) and translation (mRNA → protein).
2. rRNA forms the ribosome structure; mRNA carries DNA's code to ribosomes; tRNA delivers amino acids to ribosomes.
3. Experiments (e.g., Avery-MacLeod-McCarty, Hershey-Chase) showed DNA transfers genetic traits, not proteins.
4. RNA polymerase catalyzes mRNA synthesis by transcribing DNA's nucleotide sequence.
5. Later discoveries: some genes code for non-enzyme proteins, single genes make multiple proteins via alternative splicing.
6. The number of codons is calculated by $4^n$ where $n$ is the number of bases per codon.

Answer:

1. DNA code is converted to protein via transcription (DNA to mRNA) and translation (mRNA to protein).
2. rRNA: Forms ribosome structure; mRNA: Carries DNA code to ribosomes; tRNA: Delivers amino acids to ribosomes.
3. Experiments proved DNA (not proteins) transfers genetic information for species characteristics.
4. RNA polymerase synthesizes mRNA by transcribing DNA's nucleotide sequence.
5. Modifications reflect that genes code for non-enzyme proteins and single genes produce multiple proteins.
6. 256