Genetic Expression

Introduction: After getting a brief look at the basics concerning DNA and RNA, now it is time to look at transcription and translation. These are the two steps in genetic expression. An important thing to remember is that DNA is transcribed and RNA is translated.

Transcription
“DNA is read to make a mRNA in the nucleus.” Simply, the DNA will open up and an mRNA is made from the DNA template. Remember that RNA is a single strand. So after it is formed, it is separate from the DNA and the DNA will have closed back up.

(This example of transcription came from www.scientificpsychic.com)

Translation

“Reading the mRNA to make a protein in the cytoplasm.” This is not going on in the nucleus. After the mRNA has been made, it travels outside the nucleus to the cytoplasm. It finds a ribosome and they connect, lining up amino acids according to mRNA sequence.

(oak.cats.ohiou.edu is where I found this image of translation.)

The two of these combined make up genetic expression, but it is also controlled. Here is a list of the different ways regulation may take place:

1. Transcriptional Control: Mechanisms in the nucleus regulate which genes are transcribed and/or the rate at which transcription of genes occurs
2. Posttranscriptional Control: Occurs after DNA is transcribed and mRNA is formed. It will determine how mRNA is processed before it leaves the nucleus and also how fast it may leave.
3. Translational Control: This happens in the cytoplasm and it looks over the life expectancy of an mRNA in the cytoplasm.
4. Posttranslational Control: Also happening in the cytoplasm, but occurs after protein synthesis. The mRNA may need to undergo some additional changes.

DNA Technology

The technology surrounding DNA is ever growing. Some things that are happening now include:

Gene Isolation

Gene Cloning

Specific DNA Sequences Cloned

Genetically Engineered Products

Most, if not all, of this technology is shrouded by ethical issues though. Especially when it comes to cloning and genetic engineering. Many people are fearing for their overall health.

Conclusion: After a very brief over view of some key highlights about RNA and DNA, it is now time to look at how cells divide.