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All living creatures of all kinds and the kingdoms to which they belong carry within them a genetic material (viruses, bacteria, plants, animals, humans), and this material is responsible for transmitting traits from parents to children or across generations. The genetic material is a nucleic acid, and the nucleic acids are divided into two types: RNA and DNA.
The deoxyribonucleic acid (DNA) is a molecule made up of a group of atoms linked together by both covalent and non-covalent bonds forming a double helix structure as it shown in the picture.
The DNA represents the blueprint of the organism, and it is self-replicating. It holds the information responsible for programming all of the cell’s activities.
The deoxyribonucleic acid is made up of nucleotide , each nucleotide consists of deoxy sugar, phosphate group and a nitrogenous base.
There are 4 Nitrogenous bases:
- Adenin A
- Guanine G
- Cytosine C
- Thymine T / uracil U in RNA
The structure of DNA is a double helix, resembling the shape of a twisted ladder. Sugar and phosphates are the nucleotide strands that make up the long chains. The nitrogen bases are grades. Each grade is actually two types of nitrogen bases that combine together to form a full pitch and carry long strands of nucleotides together. Remember, there are four types of nitrogen bases, and they specifically combine together – adenine pairs with thymine A = T with two hydrogen bonds, and guanine with cytosine C = G with three hydrogen bonds.
The C and T bases, which have only one ring, are called pyrimidine, while the A and G bases, which have two rings, are called purines.
What is a gene?
The gene is the basic functional unit of heredity, made up of DNA, in some cases RNA. Some genes code for proteins.
People have about 20,000-25,000 genes, according to the Human Genome Project. Genes also vary in size from a few hundreds of DNA bases to more than two million bases.
Each of us carries two copies of each gene, one inherited from the mother and the other copy from the father. All humans carry around 99% of the same genes. What makes the difference between each individual and the other is approximately 1% of genes in each. https://ghr.nlm.nih.gov/primer/basics/gene
Did you know that only 2% of the DNA is what has been understood and studied so far, while the remaining 98% are not fully understood yet?