What is a typical gene?
Genes are composed of DNA and typically have promotor region and terminator region attach. The basic function of the gene is to transcribed RNA and then protein. But there are some genes whose function is not to make protein but they make other classes of RNA like ribosomal RNA and transfer RNA.
How genetic information processing take place in the cell?
- DNA that has the promotor region and than the intron and exon region and at the end there is the terminating region.
- It will undergo transcription process and make primary transcript of the RNA that has only exon and intron region.
- After processing intron region removes and RNA new transcript only have start codon that is AUG and exon region and at the end stop codon so now this is the functional RNA.
- Now this RNA that is functional undergo translation mechanism and passes through it all stages that are initiation stage than elongation process and at the end there is the termination.
- The translation product is protein that undergo folding process than targeting process and at the end decorating.
Different types of RNA:
Types of RNA that are found both in prokaryotic and eukaryotic organisms are:
- Transfer RNA
- Messenger RNA
- And ribosomal RNA
Types of RNA that are commonly present only in eukaryotic organisms are:
- Small interfering RNA
- Small nuclear RNA
- microRNA
detail about these different types of DNA:
Messenger RNA:
It is single strand of RNA and has genes that are complementary to the any of strand of DNA.it has codon that ensure the proper sequence of amino acid that are required to attach properly to make protein. It make as primary transcript of RNA during the process of transcription of DNA and it makes in nucleus and after that move out of nucleus through the nuclear pore in to the cytoplasm where ribosomes are present which read these transcript and make polypeptide chain that after many process turn into function protein. So it actually work as a template that is used by the ribosome for the protein manufacturing
.
Transfer RNA:
These work as an adaptor molecule that are made up of RNA. These are smallest among all types of RNA. It works as a physical carrier among mRNA and the required amino acid to sequence protein. Its main function is the transfer of amino acid unit to the ribosome that is the factory of protein. The inter-molecular base pairing ford tRNA into a tertiary structure. tRNA has hair-pin that is of leave shape.
Ribosomal RNA:
The protein manufacturing factory in the cell that we call ribosome, these RNA are the part of this ribosome organelles. So ribosomal RNA along with ribosome participate in the translation of mRNA and then in the synthesis of protein.
Small nuclear RNA:
It is the sub-type of small RNA molecule. Its basic function is that it plays its role in the splicing of primary formed mRNA transcript that is formed from DNA, and the newly form messenger RNA transcript is now mature mRNA. There are known total 6 types of SnRNA: U-1 type, U-2 type, U-3 type, U-4 type, U-5 type, and U-6 type. The function of these types of SnRNA is to remove intron part from primary mRNA.
Micro RNA:
It is the non-coding type of RNA. It can be found in plants animals and viruses too. Its main role is that it can silence RNA and plays role in the post transcriptional regulation of expression of genes. It forms base pair with the complementary sequence of the mRNA and then perform its function.
Small interfering RNA:
It is the small non-coding having double strand RNA. Its similarity match with micro RNA. It is used in the laboratory to silence the gene of interest. It perform its function by forming it form base pair with the specific complementary sequence of the nucleotide so in this way it block primary mRNA that form after transcription, to perform translation activity.
Characteristics of genetic code:
- genetic code is universal for all living organism living in this planet.
- One codon can only code for one amino acid that property is called unambiguous nature of genetic code.
- But it can happen that there is more than one codon that code for only one amino acid this property is called redundancy
- Genetic codon can be able to read as long as they are the set of total three letter series. If there is any change in punctuation or there is presence of space between letter these types of codon are not able to read. This is the continuity property of genetic code.
Function of protein:
- Most of the protein in the body are enzymes that are catalytic in nature and perform catalytical chemical reaction in the body
- Protein can also perform the function of transport. There are a lot of molecule that require carrier to move across cell membrane here hemoglobin is one of the example of protein that perform this type of function. In the body membrane proteins are present whose purpose is to transport molecule across membrane.
- Protein also perform the function of storage. Protein store amino acid. During seed germination proteins that are most abundant are broken down to get amino acid .
- Protein also involve in the motion in human body like during muscle contraction and relaxation this task is perform by the participation of actin and myosin protein. Similarly movement of organelles in a cell and movement of chromosome is perform by the intracellular components which are tubulin protein.
- Mechanical support is also provided by protein as it is the part of cell wall and membrane
- Protein plays its role in the signaling transduction like there are environmental stimuli so for their response ,receptors several hormone that protein in nature and other component of signaling pathway that are itself protein and take part in activation and inactivation of other protein, these are needed for the proper growth and differentiation of cells in living organism.
- Many protein interact with the DNA and take part in the compact packing of the chromosome. And many transcriptional factors are also protein that bind with the complementary sequence and regulate transcription of DNA. Many protein are the component of telomere and centromere
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