how was the existence of mRNA fit in the theory of DNA and RNA? and its important?
Answers
The central dogma of molecular biology suggests that DNA maintains the information to encode all of our proteins, and that three different types of RNA rather passively convert this code into polypeptides. Specifically, messenger RNA (mRNA) carries the protein blueprint from a cell's DNA to its ribosomes, which are the "machines" that drive protein synthesis. Transfer RNA (tRNA) then carries the appropriate amino acids into the ribosome for inclusion in the new protein. Meanwhile, the ribosomes themselves consist largely of ribosomal RNA (rRNA) molecules.
However, in the half-century since the structure of DNA was first elaborated, scientists have learned that RNA does much more than simply play a role in protein synthesis. For example, many types of RNA have been found to be catalytic--that is, they carry out biochemical reactions just like enzymes do. Furthermore, many other varieties of RNA have been found to have complex regulatory roles in cells.
Thus, RNA molecules play numerous roles in both normal cellular processes and disease states. Generally, those RNA molecules that do not take the form of mRNA are referred to as noncoding, because they do not encode proteins. The involvement of noncoding mRNAs in many regulatory processes, their abundance, and their diversity of functions has led to the hypothesis that an "RNA world" may have preceded the evolution of DNA and proteins (Gilbert, 1986).
Answer:
The RNA world is a hypothetical stage in the evolutionary history of life on Earth, in which self-replicating RNA molecules proliferated before the evolution of DNA and proteins. The term also refers to the hypothesis that posits the existence of this stage.
A comparison of RNA (left) with DNA (right), showing the helices and nucleobases each employs
Alexander Rich first proposed the concept of the RNA world in 1962,and Walter Gilbert coined the term in 1986.Alternative chemical paths to life have been proposed, and RNA-based life may not have been the first life to exist.Even so, the evidence for an RNA world is strong enough that the hypothesis has gained wide acceptance. The concurrent formation of all four RNA building blocks further strengthened the hypothesis.
Like DNA, RNA can store and replicate genetic information; like protein enzymes, RNA enzymes (ribozymes) can catalyze (start or accelerate) chemical reactions that are critical for life.[8] One of the most critical components of cells, the ribosome, is composed primarily of RNA. Ribonucleotide moieties in many coenzymes, such as acetyl-CoA, NADH, FADH, and F420, may be surviving remnants of covalently bound coenzymes in an RNA world.[9]
Explanation:
HOPE THIS WILL HELP U