Chapter 12, Problem 1TY

Which of the following best represents the central dogma of gene expression?

1. a. During transcription, DNA codes for polypeptides.
2. b. During transcription, DNA codes for mRNA, which codes for polypeptides during translation.
3. c. During translation, DNA codes for mRNA, which codes for polypeptides during transcription.
4. d. none of the above

Summary Introduction

Introduction: The central dogma represents the core of gene expression. The gene is made up of DNA and the information stored in the particular segments of DNA impacts cell and organs. Central dogma gives away the direction of the expression and the flow of information.

Answer to Problem 1TY

Correct answer: The best description of a central dogma according to the expression of the gene is “during transcription, DNA codes for mRNA, which codes for polypeptides during translation”. Hence, the correct answer is option b.

Explanation of Solution

Reason for correct answer:

Gene is made up of the DNA and the information stored in the gene cannot be directly changed into protein. According to the central dogma, the DNA of the gene helps in the formation of mRNA by transcription. Translation of the mRNA sequence helps in the synthesis of a protein.

Option b. is given as “During transcription, DNA codes for mRNA, which codes for polypeptides during translation.”

The central dogma represents transcription of a gene followed by translation to be the sequence for gene expression. Hence, the correct answer is option b.

Reasons for incorrect answer:

Option a. is given as, “During transcription, DNA codes for polypeptides”.

The transcription involves the formation of mRNA from DNA. It does not involve DNA to directly code for polypeptides. Hence, option a. is incorrect.

Option c. is given as, “During translation DNA codes for mRNA, which codes for polypeptides during transcription”.

The process of synthesis of mRNA from DNA is called transcription. Translation of the mRNA sequence helps in the synthesis of a protein. Hence, option c. is incorrect.

Option d. is given as, “none of the above”.

The given option b describes the correct expression of the central dogma of gene expression. Hence, option d. is incorrect.

Hence, the options a., c., and d. are incorrect.

Conclusion

Hence central dogma states that the DNA of the gene helps in the formation of mRNA by transcription, and translation of the mRNA sequence helps in the synthesis of protein.