Question at position 4 which answer is the best depiction of the normal flow of genetic information? Protein ⟶DNA ⟶ RNARNA ⟶DNA ⟶ ProteinDNA ⟶RNA ⟶ ProteinProtein ⟶RNA ⟶ DNAClear my selection单项选择题
A
Protein ⟶ DNA ⟶ RNA
B
RNA ⟶ DNA ⟶ Protein
C
DNA ⟶ RNA ⟶ Protein
D
Protein ⟶ RNA ⟶ DNA

Question

Question at position 4 which answer is the best depiction of the normal flow of genetic information? Protein ⟶DNA ⟶ RNARNA ⟶DNA ⟶ ProteinDNA ⟶RNA ⟶ ProteinProtein ⟶RNA ⟶ DNAClear my selection单项选择题

A

Protein ⟶ DNA ⟶ RNA

B

RNA ⟶ DNA ⟶ Protein

C

DNA ⟶ RNA ⟶ Protein

D

Protein ⟶ RNA ⟶ DNA

BlackTom AI · Accepted Answer

To evaluate the question, I’ll compare each proposed flow to the central dogma of molecular biology, which states that genetic information typically moves from DNA to RNA and then to protein.
Option 1: 'Protein ⟶ DNA ⟶ RNA' This sequence starts with protein and then goes backward to DNA and RNA, which contradicts the established direction of genetic information flow. Proteins are the end products, not the starting template for information transfer in normal cellular processes, so this is inaccurate.
Option 2: 'RNA ⟶ DNA ⟶ Protein' This order places RNA as the initial information carrier and then proceeds to DNA, implying reverse transcription followed by translation in a linear, single pathway. While reverse transcription exists in some contexts, the standard, widely accepted flow recognized in biology is DNA → RNA → Protein, not RNA → DNA → Protein, so this option misrepresents the typical sequence.
Option 3: 'DNA ⟶ RNA ⟶ Protein' This sequence aligns with the canonical pathway: transcription converts DNA into RNA, and translation uses RNA to synthesize proteins. It reflects the core process by which genetic information expressed in genes is ultimately used to make functional molecules, so this option matches the normal flow.
Option 4: 'Protein ⟶ RNA ⟶ DNA' This path suggests that proteins influence RNA and DNA in a directional chain, which is inconsistent with the directional flow of genetic information in cells. It reverses the established order and confuses the roles of these biomolecules, making it incorrect.
Overall, each non-conforming option deviates from the standard model (DNA → RNA → Protein) by reversing direction, misplacing roles, or proposing noncanonical routes, whereas the third option correctly mirrors the central dogma’s sequence.