Question

What are the two internal factors and two external factors that can affect gene expression?

Answer 1

Hint: Gene expression is defined as the process by which the information which is stored in the gene is converted into functional gene products that are mostly proteins, which then affect a phenotype of an organism.

Complete answer:
The gene expression involves several processes such as transcription, splicing, translation and post-translational modification in eukaryotes. Transcription is the process where RNA, mostly mRNA, is produced from DNA by the help of RNA Polymerase. Following transcription processing of the mRNA takes place which is also known as mRNA splicing that makes the mRNA ready for translation. During the splicing of mRNA the introns are removed along with the addition of a 5’ cap and a 3’ tail. This is followed by translation where the information of the mRNA is converted into proteins by the help of ribosomes. The proteins formed as a result of translation are in the form of an unfolded polypeptide that needs to be folded into a functional form which is known as the post-translational modification. Regulation of gene expression helps to give control over the location, the timing and the amount of gene present in a cell at a particular time. Internal factors that affect gene expression include hormones, gender and metabolic activities. External factors include temperature, light and other chemicals which might be taken with food.

Note:
Thus gene expression is a very important phenomenon that leads to the production of functional proteins from the genetic information of the DNA. Gene expression should be tightly regulated because unregulated expression may lead to production of non-functional proteins that have a negative effect on the phenotype of the individual.