The accompanying illustration shows a portion of a gene undergoing transcription. The template and coding strands for the gene are labeled, and a segment of DNA sequence is given.

For this gene segment, write the polarity and sequence [TIP 1] of the RNA transcript from the DNA sequence given.

Verified step by step guidance

1. Identify the template strand and the coding strand from the given DNA sequence. The template strand is the strand that RNA polymerase reads to synthesize RNA, while the coding strand has the same sequence as the RNA (except thymine is replaced with uracil in RNA).
2. Determine the polarity (5' to 3' direction) of the template strand. RNA synthesis occurs in the 5' to 3' direction, so the RNA transcript will be complementary to the template strand and antiparallel in polarity.
3. Using base-pairing rules, transcribe the RNA sequence from the template strand. Replace adenine (A) in the DNA template with uracil (U) in RNA, thymine (T) with adenine (A), cytosine (C) with guanine (G), and guanine (G) with cytosine (C).
4. Write the RNA sequence with its polarity explicitly labeled (e.g., 5' to 3'). Ensure that the sequence is written in the correct direction, starting from the 5' end.
5. Double-check the RNA sequence by comparing it to the coding strand of DNA. The RNA sequence should match the coding strand (except for the replacement of thymine with uracil) and have the correct polarity.

Key Concepts

Transcription

Transcription is the process by which the genetic information encoded in DNA is copied into messenger RNA (mRNA). During transcription, RNA polymerase binds to the DNA template strand and synthesizes a complementary RNA strand, following base-pairing rules where adenine pairs with uracil (instead of thymine) and cytosine pairs with guanine.

Polarity of Nucleic Acids

Nucleic acids, including DNA and RNA, have directionality, often referred to as polarity. The two ends of a nucleic acid strand are designated as the 5' (five-prime) and 3' (three-prime) ends, indicating the orientation of the sugar-phosphate backbone. RNA is synthesized in the 5' to 3' direction, meaning that nucleotides are added to the 3' end of the growing RNA strand.

Base Pairing Rules

Base pairing rules dictate how nucleotides pair with each other during the processes of DNA replication and transcription. In DNA, adenine pairs with thymine, and cytosine pairs with guanine. However, during transcription, uracil replaces thymine in RNA, so adenine in the DNA template pairs with uracil in the RNA transcript, while cytosine still pairs with guanine.