For the sequences given in the following list, indicate whether DNA replication, transcription, pre-mRNA processing, or translation will be most immediately affected by deletion of the sequence. As precisely as you can, specify what step of the process is directly affected by the deletion.

a. start codon
b. TATA box
c. 5' splice site
d. ori sequence
e. -10 consensus sequence
f. Shine–Dalgarno sequence
g. 5' cap
h. termination sequence

Verified step by step guidance

1. span>a. Start Codon: The start codon is crucial for the process of translation. Its deletion would directly affect the initiation step of translation, as it signals the ribosome where to begin protein synthesis.</span
2. span>b. TATA Box: The TATA box is a DNA sequence that indicates where a genetic sequence can be read and decoded. It is essential for transcription initiation. Deletion of the TATA box would affect the binding of RNA polymerase and transcription factors, thus impacting the initiation of transcription.</span
3. span>c. 5' Splice Site: This sequence is important for pre-mRNA processing, specifically during the splicing step. Deletion of the 5' splice site would prevent the proper removal of introns from pre-mRNA, affecting mRNA maturation.</span
4. span>d. Ori Sequence: The origin of replication (ori) is a sequence where DNA replication begins. Deletion of the ori sequence would directly affect the initiation of DNA replication, as it is the site where replication machinery assembles.</span
5. span>e. -10 Consensus Sequence: This sequence is part of the promoter region in prokaryotes and is crucial for transcription initiation. Deletion of the -10 consensus sequence would affect the binding of RNA polymerase, thus impacting the initiation of transcription.</span

Key Concepts

DNA Replication

DNA replication is the process by which a cell duplicates its DNA before cell division. It involves unwinding the double helix and synthesizing new strands complementary to the original ones. Key elements include origins of replication (ori sequences) that signal where replication begins. Deletion of these sequences can halt the replication process, preventing the cell from properly copying its genetic material.

Transcription

Transcription is the process of synthesizing RNA from a DNA template, where RNA polymerase binds to specific DNA sequences to initiate RNA synthesis. Important elements include promoter regions like the TATA box and consensus sequences that help in the binding of transcription factors. Deleting these elements can disrupt the initiation of transcription, leading to reduced or absent RNA production.

Pre-mRNA Processing

Pre-mRNA processing involves several modifications to the primary RNA transcript before it becomes mature mRNA. This includes the addition of a 5' cap, splicing out introns at splice sites, and polyadenylation at the 3' end. Deletion of critical elements like the 5' splice site or the 5' cap can severely affect the stability and translation of the mRNA, ultimately impacting gene expression.