How Many Genes are Present in a Chromosome

Introductions

A chromosome contains hundreds to thousands of genes. Chromosomes, which are in the cell nucleus by themselves, contain genes. A normal human cell has 23 pairs of chromosomes, i.e. 46 chromosomes. Genes are used to determine the traits of a human, which are generally determined by one or more genes, these genes mutate to give newer traits in the individual, resulting in what we call evolution, over a longer duration of time. Humans have approximately 20000-23000 genes in every cell.

What are Genes

Genes consist of deoxyribonucleic acid (DNA), which contains the prototype of how the protein needs to be synthesised. Genes vary depending on the type of protein they are going to synthesise. A DNA molecule is a long double helix in structure. The double helix structure is made when adenine (A) is paired with thymine (T), and guanine (G) is paired with cystine (C), through hydrogen bonds.

How Important are Proteins for Human Body

Proteins are made up of a long chain of amino acids chained together; there are a total of 20 different amino acids, of which some can be developed by the enzymes in the body while the rest needs to be taken from our diet, which is also called "essential amino acids." The chain of amino acids folds itself into a 3-D structure, and it is this shape that determines the functionality of the protein in the body. This folding is dependent upon the specific sequence of amino acids, and thus, in this way, it gives rise to different functionalities.

How Protein is Coded in DNA

The type of protein to be synthesised in the gene is coded in the form of triplets in DNA.

Specific sequences of three bases for DNA code for specific amino acids like GCT, codes for alanine, GTT codes for valine, etc.

Transcription

It is the process in which information coded in DNA is transformed into RNA (ribonucleic acid), RNA is a single strand of bases, with everything being similar except uracil (U), which replaces the thymine. During transcription, a strand of DNA acts as a template using which RNA is formed, and that RNA is called mRNA (or messenger RNA), after which it leaves the nucleus, travels to the cytoplasm, and gets attached to ribosomes where protein synthesis occurs.

Translation

After mRNA gets attached to ribosomes, it tells the order of amino acids to be linked together, which is facilitated by a type of RNA known as tRNA (transfer RNA), Every molecule of tRNA brings an amino acid, to link in an increasing sequence of a protein, which gets folded into a three-dimensional structure due to the presence of nearby molecules.

This is how protein gets synthesised, which can be further used for the production of enzymes, gene expression, and so on.

Mutation

Due to the huge sequence of bases being replicated, and some margin of error in the replication, which may lead to some difference in the original DNA and replicated DNA, these differences may be passed on to the upcoming generations, and may undergo natural selection, leading to changes in the structure and function of their body parts from their previous generation, which, when occurring for a longer period, can be called the evolution of the being.

Every creature on this planet is a result of evolution.

Conclusions

DNA (or deoxyribonucleic acid) can be called a building block of a creature, as it is its replication that paves the path for the creation of a new human being. Without proper gene expression, an organism can't live its life in peace.