A DNA sequence encoding a five-amino acid polypeptide is given below.
...ACGGCAAGATCCCACCCTAATCAGACCGTACCATTCACCTCCT...
...TGCCGTTCTAGGGTGGGATTAGTCTGGCATGGTAAGTGGAGGA...
Locate the sequence encoding the five amino acids of the polypeptide, and identify the template and coding strands of DNA.

Verified step by step guidance

1. Step 1: Understand the problem. The DNA sequence provided encodes a five-amino acid polypeptide. To locate the sequence encoding the polypeptide, you need to identify the coding strand and template strand, and then determine the mRNA sequence and corresponding amino acids.
2. Step 2: Identify the coding strand and template strand. The coding strand is the strand that matches the mRNA sequence (except thymine is replaced by uracil in mRNA). The template strand is complementary to the coding strand and is used by RNA polymerase to synthesize mRNA.
3. Step 3: Locate the start codon (AUG) in the coding strand. The start codon signals the beginning of translation. Scan the coding strand for the sequence 'ATG' (start codon in DNA) and identify the subsequent codons that encode the five amino acids.
4. Step 4: Transcribe the coding strand into mRNA. Replace thymine (T) with uracil (U) in the coding strand to generate the mRNA sequence. For example, if the coding strand contains 'ATG', the mRNA sequence will contain 'AUG'.
5. Step 5: Translate the mRNA sequence into amino acids. Use the genetic code table to match each codon in the mRNA sequence to its corresponding amino acid. Continue until you have identified the five amino acids encoded by the sequence.

Key Concepts

DNA Structure and Function

DNA is composed of two strands forming a double helix, with each strand made up of nucleotides. Each nucleotide consists of a sugar, a phosphate group, and a nitrogenous base (adenine, thymine, cytosine, or guanine). The sequence of these bases encodes genetic information, including the instructions for synthesizing proteins, which are made up of amino acids.

Transcription and Translation

Transcription is the process by which the DNA sequence of a gene is copied into messenger RNA (mRNA). This mRNA then undergoes translation, where ribosomes read the mRNA sequence in sets of three nucleotides (codons) to assemble the corresponding amino acids into a polypeptide chain, ultimately forming a protein.

Template and Coding Strands

In DNA, the template strand is the strand that is read by RNA polymerase during transcription to synthesize mRNA, while the coding strand has the same sequence as the mRNA (except for thymine being replaced by uracil). Identifying these strands is crucial for understanding how the genetic code is expressed in proteins.