DNA and RNA ~ Genetic Material
The compound between protein and nucleic acid is called protein nucleo. Nucleo proteins are constituents of chromosomes. Of the two compounds, only nucleic acids can carry genetic information from a parent to her offspring. So, actually nucleic acid is a genetic material or a factor of heredity, although chromosomes are commonly referred to as heredity factors. Nucleic acid as DNA material consists of DNA (deoxyribonucleic acid) and RNA (ribonucleid acid). To find out about DNA and RNA, let's look at the following description.
1. DNA (Deoxyribonucleic Acid)
From various studies revealed that DNA is a carrier of most or all genetic traits in chromosomes. DNA is present in the nucleus and together with protein compounds form a protein nucleo. Besides in the nucleus, DNA molecules are also found in mitochondria, plastids, and centrioles. The chemical makeup of DNA is a complex macromolecule. DNA molecules are composed of two very long polynucleotide chains. One polynucleotide chain consists of a series of nucleotides. A nucleotide is composed of:
a) Deoxyribose sugar group (sugar with five carbon atoms or pentose)
b) Phosphoric acid group (phosphate bound to the fifth C of sugar)
c) Nitrogen base group (this group is bound to the first C of sugar)
Nitrogen bases can be classified into two, namely purine bases and pyrimidine bases. Purine bases consist of adenine (A) and Guanin (G), while pyrimidine bases consist of cytosine (S) and thymine (T).
Sugar with a base forms a bond between C in sugar and N in the purine base and N-H in the pyrimidine base. The compounds formed are called nucleosides or deoxyribonucleosides.
Nucleosides can be divided into four types, namely:
1) Compounding between sugar and base adenine (deoxy adenosine).
2) Compounding between sugar and base guanine (deoxy guanosin).
3) Compounding between sugar and thymine base (deoxitimidin).
4) Compounding of sugar with cytosine base (deoxycididin).
Furthermore, phosphates form esters with nucleosides through the formation of C5 bonds in sugar. These 5-nucleoside phosphate esters are called nucleotides. There are 4 types of nucleotides, namely adenosine deoxyribonucleotide, deoxyribonucleotide guanosine, deoxyribonucleotide cytidine, and thymidine deoxyribonucleotide. These nucleotides can combine to form a series called polynucleotides. Twisting polynucleotide threads (double helices) form DNA. Based on the results of X-ray refraction analysis by DNA crystals, James Watson (America) and Francis Crick (England) in 1953 concluded that the structure of DNA molecules is in the form of double helices.
DNA molecules have properties, including:
a. The DNA of various organisms has the same adenine (A) content as Thymine (T). The difference between the DNA of different species lies between the contents of A + T or G + C.
b. Each DNA molecule is composed of two polynucleotide chains. The bases of the two chains are paired with adenine rules pairing with Thymine and Guanine pairing with cytosine. Between two paired bases a hydrogen bond is formed. The existence of this bond gives flexibility to DNA.
c. DNA is a structure that actively performs biological functions.
2. RNA (Ribonucleic Acid)
In the cells of prokaryotic and eukaryotic organisms, in addition to DNA there are also other important nucleic acids, namely RNA or ribonucleic acid. RNA is a single thread composed of ribose sugar molecules, phosphate groups, and nitrogen acids. Nitrogen RNA bases consist of purines (adenine and guanine) and pyrimidine classes (cytosine and uracil). RNA is formed by DNA in the nucleus, through the process of DNA transcription. The transcription results are used RNA for protein synthesis in the cytoplasm of cells.
Based on the location and function, RNA can be divided into three types, namely:
a) ambassador RNA (RNA-d) or m RNA
The ambassador's RNA is the RNA that forms the template in the process of preparing amino acids in polypeptide chains or protein synthesis. Called RNA ambassador, because this molecule is the link between DNA and protein and carries messages in the form of genetic information from DNA to form proteins. Genetic information is in the form of an N-base sequence in the RNA of an ambassador ordering an amino acid called a codon. The formation of the polypeptide chain depends on the order of the codons in the RNA ambassador. The order of codons in DNA-printed RNA-d depends on the type of protein to be synthesized.
b) RNA transfer (RNA-t)
RNA-t has the function of translating codons contained in RNA-d into one type of amino acid. The ability to translate is caused by the presence of anti-codon which is a complement of the RNA-d codon. RNA-t also functions to transport amino acids to the surface of the ribosome at the time of translation. Translation is the translation of the RNA-d nucleotide sequence into the amino acid polypeptide sequence.
c) ribosomal RNA (RNA-r)
RNA-r is the most RNA, about 83% of the RNA contained in a cell. RNA-r plays a role in protein chain synthesis as a meeting point for RNA-d and RNA-t. RNA and DNA have differences