FUNDAMENTALS OF MOLECULAR BIOTECHNOLOGY-WHAT IS A GENE?

 GENE TECHNOLOGY -CONCEPTS

The main purpose of this article is everybody has a right to have a piece of minimum knowledge in molecular biology as in this pandemic COVID-19 situation, people should have at least an idea of what is going on around them to sight a solution for this adamant and strange microbiome.

Molecular biotechnology or Molecular Biology are interchangeable names to the branch of Biology, which mainly deals with the molecular behavior, changes, techniques of nucleic acid replications transcriptions and translations, and genetical modifications,etc.etc.

What are Eukaryotic and Prokaryotic Cells?

Prokaryotic cells are cells that have no defined nuclei.

e.g. Bacteria and other unicellular organisms.

Eukaryotic cells are cells that have a defined nucleus. (e.g.) human beings and other multicellular organisms.

What are the nucleic acids?

These acids are the basics of the nucleus of a cell whether the cell is prokaryotic or eukaryotic.

 RNA:-

Fig-1

Ribo Nucleic Acid. The chemical structure contains a ribose sugar attached with a purine or pyrimidine moiety at its 1st carbon position and a phosphate moiety at its 3rd carbon position. The other end of the phosphate moiety is attached with the 5th carbon position of another ribose sugar with a nitrogen base attached with its 1st carbon position. Thus a chain of ribose sugars with nitrogen bases attached by phosphate bonds is fabricated as a single RNA strand. (see Fig-1)

 DNA:-

Fig-2A

Deoxy Ribo Nucleic Acid. The chemical structure contains deoxyribose sugars attached with nitrogen bases bonded with phosphate bridges to form DNA strands. But unlike RNA, DNA is mostly available in double-stranded form.

The pentose sugar in the DNA is deoxygenated at the C'-2 position to have two hydrogen ions (one oxygen is removed) to it (H-C-H) as in the Fig-2A above. That is why it is known as deoxyribose and is more stable than ribose as the later contains oxygen at C'-2 position as (H-C-OH)

Each strand is composed of a deoxyribose ring carrying a nitrogen base (ADENINE) at the 1st carbon position attached with another deoxyribose ring with a phosphate bridge at the 5th carbon position at one end and the third carbon position at the other end. (Fig-2A)

Both RNA and DNA strands fabricated in a similar manner except one of the nitrogen bases namely thymine in DNA is replaced by uracil in RNA. Moreover, RNA is mostly occurring as a single strand whereas DNA is occurring as a double-strand spun together in a helical manner. (Fig-2B)

Fig-2B

What is a nucleotide? Nucleotides are the fundamental units of a nucleic acid strand. Every RNA and DNA strands are composed of nucleotides.

Fig-2C

Nucleotides are formed by the following equations:

A pentose back-bone+ a nitrogen base ⟶Nucleoside

A nucleoside + phosphate bonds⟶Nucleotide

A single nucleotide can be formulated as follows:

As in Fig- 2C, there are 5 nucleosides each with a pentose sugar backbone and each carrying nitrogen bases indicated by colored bands bonded together to form polynucleotides.

A pentose sugar + phosphate+ a nitrogen base.

Fig-2D

In RNA nucleotide the pentose sugar is ribose and one of the five nitrogen bases is uracil while in the DNA chain the pentose sugar is deoxyribose and one of the nitrogen bases is thymine which replaces uracil in the RNA chain. The phosphate moiety is bonding between pentoses to form the RNA or DNA backbone.

What are chromosomes?

Chromosomes are like threads made of tightly packed DNA strands packed with histones.

Fig-3

Chromosomes are formed from the twisted chain of double-stranded DNA that wrapped tightly around the pieces of proteins called histones and spun to form a rope known as chromatin which further spun tightly to form a perfect thread of chromosome (Fig-3)

In simple words, chromosomes are made of tightly wrapped DNA molecules around histones to form pairs in a eukaryotic cell nucleus.

There are about 23 pairs of chromosomes in the human cell nucleus.

A gene is any single segment of the chromosome thread which contains the heredity pieces of information including synthesizing building and demolishing or reconstructing proteins quantitatively. Genes decide the man about who he is at present and who he should be in the future. A single gene contains clear information about, physical behavior, growth, characters, and many many things.

A gene is a segment in the chromosome with a clear reading written by the jumbled nucleotide letters.

(e.g.)

Th iswh at Itr yt oexp lain-Nucleotides

This is what I try to explain-A gene

From the above anagrams, we can say nucleotides are single alphabets in a chromosome thread in an irregular scattered or jumbled manner by which a genetic character is fabricated to form a single gene.

Hence, in other words, nucleotides are scattered or jumbled chemical letters in a chromosomal thread in which a gene is fabricated by rearranging the letters to form a correct meaningful sentence that expresses a clear character. 

Thus chromosome contains many genes embossed in it.

In a human eukaryotic cell, there are 23 pairs of chromosomes of the total 46 chromosomes present.

Equation of the gene formation from the origin to end.                                                         DNA POLYMERASE

Proteins➝Nucleobases➡️Nucleotides⟶RNA⟶↲

DNA➡️DNA Helicase⟶DNA double-strand➡️histones➡️

Chromatins➡️Chromosomes➡️GENES (Fig-3)

Equation For Cell Protein Synthesis

Chromosomes➡️Chromatin➡️DNA➡️Genetic Copy(Transcription) mRNA➡️Translation by tRNA➡️Protein Synthesis by rRNA in Ribosomes.

Protein synthesis is a cyclic phenomenon. Proteins are essential for the cells to live. A cell uses proteins to make all of its contents of protoplasm, cytoplasmic organelles, nucleus, DNA, RNAs chromosomes, nucleotides, and genes. Again the gene instructs the organelle to synthesize protein. Hence it is a wonderful cyclic phenomenon in all eukaryotic and prokaryotic cells.

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