If DNA has a sequence of AAA, then a segment of mRNA synthesized on it will have a sequence of a. TTT, b. UUU, c. GGG, d. CCC.

Verified step by step guidance

1. Identify the process involved: Transcription is the process where a segment of DNA is used as a template to synthesize mRNA.
2. Understand the base pairing rules in transcription: In DNA to mRNA transcription, adenine (A) pairs with uracil (U) instead of thymine (T), and cytosine (C) pairs with guanine (G).
3. Analyze the given DNA sequence: The DNA sequence provided is 'AAA'.
4. Apply the base pairing rules: Since adenine (A) in DNA pairs with uracil (U) in mRNA, the mRNA sequence synthesized will be 'UUU'.
5. Review the options provided: Match the synthesized mRNA sequence 'UUU' with the correct option, which is option b.

Key Concepts

DNA and RNA Structure

DNA (deoxyribonucleic acid) is a double-stranded molecule that contains the genetic blueprint of an organism, while RNA (ribonucleic acid) is typically single-stranded and plays a crucial role in protein synthesis. The key difference is that RNA contains uracil (U) instead of thymine (T), which is found in DNA.

Transcription Process

Transcription is the process by which a segment of DNA is copied into mRNA by the enzyme RNA polymerase. During this process, the DNA sequence is read, and complementary RNA nucleotides are assembled to form a strand of mRNA, where adenine (A) pairs with uracil (U) instead of thymine.

Base Pairing Rules

Base pairing rules dictate how nucleotides pair with each other during DNA and RNA synthesis. In DNA, adenine pairs with thymine, and cytosine pairs with guanine. In RNA, adenine pairs with uracil, and cytosine still pairs with guanine, which is essential for determining the mRNA sequence from the DNA template.