Q17.2-3CC - Campbell Biology

Question

Suppose X-rays caused a sequence change in the TATA box of a particular gene's promoter. How would that affect the transcription of the gene? (See Figure17.9)

Step-by-Step Solution

Answer

X-rays can change the pattern of the sequence of the TATA box. Then, the transcription factors do not recognize the TATA box sequences. The transcription process does not take place. 

Step 1: Description of gene and transcription

Gene is the segment that is found in the DNA that codes for a protein. It also carries the genetic information that is transferred from one generation to the other generation.

Transcription is the process of producing mRNA from the DNA. 

Step 2: Definition of TATA box and promoter

The core segment present in the promoter is the TATA box. It is the sequence in which there is a repetition of A and T is seen. It is otherwise known as non-coding sequences of the DNA segment. 

The promoter is the region in which the RNA polymerase can bind to it and initiate the process of transcription.

Step 3: Effect of X-ray in the TATA box

X-rays can cause a mutation in the DNA segment. The X-ray also mutates the TATA box sequences. 

The change in the TATA box sequence causes a problem in recognizing the promoter sequences by the transcription factors. If the transcription process does not recognize the promoter region, then the transcription process does not take place. 

Hence, the X-ray mutation of TATA box sequences can stop the process of transcription.