DNA And RNA As The Basic Unit Of The Living System

Also, regulation of proteins occurs at the level of DNA as well as on other levels. In some cells, certain sections of DNA are bundled tight in a mass of proteins, in such a way that no RNA (and thus no protein) can be made from them. This turns off those genes. In other sections, only a few proteins might be keeping the DNA turned off, so that it could quickly be unravelled and used to make proteins.

Transcription is a process in which genetic information from DNA is encoded onto messenger RNA, by unwinding the DNA and splicing exons and introns and coding them onto the mRNA so the DNA itself is not used directly. Translation is a process by which ribosomes reads the mRNA to determine the amino acid sequence of the protein.

Finally it was found that a total of 62.1 % to about a 74.7% of the human genome was covered by either proceed or by the help of primary transcript.

MicroRNAs (miRNA) are small noncoding RNA, usually 17-25 nucleotides long that are able to bind complementary sequences of target messenger RNA (mRNA) and to induce both their degradation and translational repression (Fortunato, et al 2014). They are one of the most significant classes of non-coding RNA molecules (eg. small interfering RNA (siRNA) and ribozymes) that act within the cell. MiRNAs are also evolutionary conserved in different species from plants to humans and are encoded by their respective genes (Bader, 2012).

Dr. Tina Henkin’s seminar “Flipping the switch: How cells use RNA to regulate genes expression”, was outlined by four general questions. The first question addressed in the seminar was “Why study Microbes?”. The next, “Why study bacterial gene regulation?”. The third question, “What are the basics of gene expression?”. Finally, “What’s special about riboswitches?”. Dr. Henkin addressed these questions throughout her seminar, which eventually led into to more specific questions of gene expression and predicted hypotheses of her model. However, to understand these more specific questions and predictions it is crucial to understand the first four questions outlined in the beginning of the seminar.

Most genes in plants and animals contain regions that code for polypeptides, called exons, with noncoding sequences called introns in between. Both introns and exons are transcribed from DNA to RNA, then RNA splicing occurs to remove the introns. Introns can contain nucleotide sequences that regulate gene activity. The splicing process may contribute to controlling the flow of mRNA from nucleus to cytoplasm. Sometimes splicing occurs in different ways, to produce different mRNA molecules from the same transcript.

This study shows that 6% of the entire annotated non-coding and coding gene transcripts are overlapping with small RNAs. Highly specific subcellular positioning is found for both unannotated & annotated short RNA.

There is some redundancy in the code as most of the amino acids may be encoded by more than one codon. Moreover, the code can be expressed as RNA or DNA codons with the former being used during translation (i.e. creation of proteins) after acquiring its sequence of nucleotides from the latter during transcription (i.e. copying of DNA into mRNA).

Most genes contain the information needed to make functional molecules called proteins. (A few genes produce other molecules that help the cell assemble proteins.) The journey from gene to protein is complex and tightly controlled within each cell. It consists of two major steps: transcription and translation. Together, transcription and translation are known as gene expression.

Genes are transcribed to yield one of three types of RNA. These RNA types include messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). Messenger RNA carries the genetic instructions needed to manufacture polypeptides. Messenger RNA is absolutely necessary, because genes cannot leave the nucleus. They pass their information to mRNA, which transports that information to the cytoplasm, where protein synthesis occurs at the ribosome.

Transcription in eukaryotes is one of the most vital processes of life that involves a highly controlled and regulated systematic series of events that is mediated through various key factors. The process of transcription occurs when the genetic information stored within DNA becomes activated through the synthesis of complementary mRNA and is thus regulated by RNA polymerases. There are three types of RNA polymerases that distinctively transcribe a specified set of genes. RNA polymerase I and III transcribe genes that have terminal products such as ribosomal subunits, tRNA and small nuclear RNA. For example, RNA polymerase I is located in the nucleolus of eukaryotic cells and is responsible for transcribing 18S, 5.8S,

Gene expression is the ability of a gene to produce a biologically active protein. This process is regulated by the cells of an organism, it is very important to the survival of organisms at all levels. This is much more complex in eukaryotes than in prokaryotes. A major difference is the presence in eukaryotes of a nuclear membrane, which prevents the simultaneous transcription and translation that occurs in prokaryotes. Initiation of protein transcription is started by RNA polymerase. The activity of RNA polymerase is regulated by interaction with regulatory proteins; these proteins can act both positively, as activators, and negatively as repressors. An example of gene regulation in cells is the activity of the trp operon. The trp

One of the fundamental discoveries of the 20th century was that DNA was the genetic code’s physical structure (Watson & Crick, 1953) and, since then, many studies have disclosed the complicated pattern of regulation and expression of genes, which involve RNA synthesis and its subsequent translation into proteins.

Transcription is where DNA is transcribed into RNA which then can be pass to the ribosome’s to act as a template for protein synthesis. Before transcription can begin DNA must unwind and the two halves of the molecule much come apart so exposing the base sequence. This process begins when a region of a two DNA strands is unzipped by enzyme called RNA polymerase attaches to the DNA molecule at the imitation site.

microRNAs are a small non-coding endogenous RNA molecule (containing about 21 nucleotides) found in plants, animals and some viruses, that functions in RNA silencing and post-transcriptional regulation of gene expression. miRNA differ from other RNA like mrna, rRNA and snoRNA by its small size approximately 21 nucleotides and it exists as stable hairpin. mRNA regulate their expression through translation repression and mRNA degradation by targeting mRNA, Various biologic pathways are related with miRNAs. About 1000 MIR present in human genome and they target about 60% of genes. (19, 20)