Question

1. in prokaryotic cells, translation begins before transcription is finished. give two reasons why this would not be possible in eukaryotic cells.

Explanation:

1. Nuclear Membrane Barrier: Eukaryotic cells have a nucleus enclosed by a nuclear membrane. Transcription occurs in the nucleus (DNA to mRNA), and translation occurs in the cytoplasm (ribosomes). The nuclear membrane physically separates these processes, so translation can’t start until mRNA exits the nucleus after transcription finishes. Prokaryotes lack a nucleus, so their DNA (in the nucleoid) is accessible to ribosomes in the cytoplasm, allowing translation during transcription.
2. RNA Processing in Eukaryotes: Eukaryotic pre - mRNA undergoes processing (capping, poly - adenylation, splicing) after transcription. These modifications are necessary for mRNA to be functional (e.g., capping helps ribosome binding, splicing removes introns). Prokaryotic mRNA doesn’t need extensive processing, so translation can start immediately as mRNA is transcribed. Without completing processing, eukaryotic mRNA isn’t ready for translation, so translation can’t precede the end of transcription.

Answer:

Two reasons are: 1. Eukaryotic cells have a nuclear membrane that separates the nucleus (where transcription occurs) from the cytoplasm (where translation occurs), preventing translation from starting before transcription finishes. 2. Eukaryotic pre - mRNA requires post - transcriptional processing (capping, poly - A tail addition, splicing) to be functional for translation, so translation can't begin until transcription and processing are complete.