What is the primary function of transcription in cells?

The primary function of transcription in cells is to create a copy of the DNA in the form of messenger RNA (mRNA). During transcription, the enzyme RNA polymerase reads the DNA sequence of a gene and synthesizes a complementary strand of RNA. This process is essential because it allows the genetic information stored in DNA to be translated into proteins, which are crucial for various cellular functions and activities.

This copying mechanism is vital for expressing genes and ensuring that the information needed for protein synthesis can be translated into the appropriate proteins at the right time in response to the cell's needs. The mRNA generated from transcription serves as a template for the subsequent process of translation, where proteins are synthesized based on the encoded information in the mRNA.

The other options do not accurately represent the process of transcription. Converting glucose into ATP is a function of cellular respiration, producing ribosomes involves a different process known as ribosome biogenesis, and packaging and transporting proteins relates to post-translational modifications and intracellular transport rather than transcription itself.