Feb 16, 2023 14:12:00

Animation that understands how complex human beings are biological machines

The human body is said to consist of approximately 60 trillion cells. YouTube channel

Kurzgesagt , which publishes animations that explain science, explains the basic knowledge of how cells function and how they perform life activities.

You Are an Impossible Machine-YouTube

Cells are structured like tens of thousands of fruits such as watermelons and grapes floating in a room filled with tens of trillions of grains of sand.

Of course, sand and fruit are just examples, real cells are made up of water and invisible small protein and sugar molecules.

Proteins make up most of the cells. Proteins are the basis of life in the human body.

Proteins are made up of compounds called amino acids. Amino acid is a general term for organic compounds having a carboxy group (-COOH) and an amino group (-NH ₂ ), some of which are used as protein materials.

In particular, amino acids that are the materials of proteins are called α-amino acids, and there are 21 types of them.

By dehydration bonding (

peptide bond ) between the carboxyl group and amino group of amino acids, they are connected like a string made of amino acids.

In life activities, amino acids are like the alphabet, and proteins are like words.

And one life activity is executed by multiple proteins. The biological activity carried out by this chain of multiple proteins is called a 'pathway', which is equivalent to a sentence.

In the case of humans, if the number of words that make up one sentence is 8000, the life language of proteins is equivalent to about 20,000 words.

In the case of English, one word has an average of about 5 letters, but in the case of protein, it is composed of about 375 amino acids.

The blueprints of such proteins are written in

deoxyribonucleic acid (DNA) in human cells. When all the DNA contained in one cell is stretched, the total length is about 2m.

It seems that if you connect all the DNA contained in one human body, it is equivalent to 20 times the distance between the earth and the sun, which is about 150 million km.

DNA has a structure in which strings connected by substances called nucleotides draw a double helix. There are four types of nucleotides: adenine, guanine, cytosine, and thymine, and the arrangement of these nucleotides is the blueprint of proteins.

In general terms, DNA is

transcribed into ribonucleic acid (RNA) and messenger RNA (mRNA) is synthesized. An organ called the ribosome reads the unnecessary information from the mRNA, and transfer RNA (tRNA) transports the amino acid corresponding to the nucleotide sequence to produce a protein. This is the most important core system for life and is called the 'Central Dogma'.

If amino acids are letters, proteins are languages, pathways are sentences, DNA is grammar, and cells are speakers.

Amino acids connected by the central dogma acquire a three-dimensional structure by folding.

This three-dimensional structure is important for proteins in their life activities. For example, there may be multiple proteins with corresponding three-dimensional structures.