During gene expression, what happens in the process called translation, which follows transcription and takes place on ribosomes?

Introduction / Context:
The central dogma of molecular biology describes the flow of genetic information from DNA to RNA to protein. First, DNA is transcribed into messenger RNA (mRNA) in a process called transcription. Then, in the process of translation, the information encoded in mRNA is used to synthesize proteins. Understanding what occurs during translation and how it differs from transcription and DNA replication is fundamental in genetics and molecular biology. This question focuses on identifying the correct description of translation.

Given Data / Assumptions:

• The process in question is translation, not transcription or replication.
• Translation occurs on ribosomes in the cytoplasm (or on rough endoplasmic reticulum).
• Options describe different processes involving DNA, RNA, and proteins.
• We assume basic familiarity with the steps of gene expression.

Concept / Approach:
Translation is the process in which ribosomes read the nucleotide sequence of an mRNA molecule in sets of three bases called codons. Each codon specifies a particular amino acid. Transfer RNA (tRNA) molecules carry amino acids to the ribosome, where their anticodons pair with the mRNA codons. The ribosome then catalyzes the formation of peptide bonds between amino acids, building a polypeptide chain in the sequence dictated by the mRNA. Thus, translation converts the nucleotide language of mRNA into the amino acid language of proteins.

Step-by-Step Solution:
Step 1: Identify translation as the step following transcription in gene expression. Step 2: Recall that during transcription, DNA is used as a template to make RNA, especially mRNA. Step 3: Recognize that translation uses mRNA as a template to assemble amino acids into a polypeptide on ribosomes. Step 4: Understand that tRNA and rRNA participate in translation, but they are not newly synthesized from mRNA during this step. Step 5: Choose the option that correctly states that the cell uses mRNA information to produce proteins.

Verification / Alternative check:
Textbooks and diagrams of gene expression often summarize the process with the phrase "DNA is transcribed to RNA, and RNA is translated to protein." In such diagrams, mRNA moves from the nucleus to the cytoplasm, where it associates with ribosomes. tRNA molecules bring specific amino acids that correspond to each codon on the mRNA. As the ribosome moves along the mRNA, it forms peptide bonds and builds a polypeptide chain. These common descriptions confirm that translation is the step where the information in mRNA is used to assemble proteins.

Why Other Options Are Wrong:
Transfer RNA molecules are synthesized directly from messenger RNA templates: tRNA is transcribed from tRNA genes in DNA, not made from mRNA. Copies of DNA molecules are made from existing DNA strands: This is DNA replication, not translation. Messenger RNA molecules are synthesized using DNA as a template: This describes transcription, not translation. Ribosomal RNA is converted directly into DNA inside the nucleus: There is no normal cellular process that converts rRNA into DNA.

Common Pitfalls:
Students sometimes confuse transcription and translation because they both involve nucleic acids. A helpful memory device is that transcription involves "writing" RNA from DNA, while translation involves "converting" the nucleotide language into the amino acid language of proteins. Another mistake is thinking that all forms of RNA are made from each other, when in reality each RNA type is transcribed from DNA. Keeping these distinctions clear will help you answer questions about gene expression accurately.

Final Answer:
During translation, The cell uses information in messenger RNA to assemble amino acids into proteins.