Chapter 17.3, Problem 1CC

Summary Introduction

To explain: How the human cells can synthesize 75,000-100,000 different proteins when there are fewer than 21,000 human genes.

Concept introduction:

In human cells, transcription process takes place in the nucleus, and the pre-mRNA is synthesized. This pre-mRNA is further modified before translation in the cytoplasm. This is known as RNA processing. It includes modification of mRNA ends and RNA splicing. During RNA splicing, the non-coding regions that is introns are excised from RNA molecules, and the coding regions are joined. Some genes undergo alternative splicing, which leads to the production of two or more different mRNAs from the same primary transcript.