Hellooo everyone! Greetings to you all.After a long break from writing I am here again. Though it's a long break bit nothing changed. I will share my experience of these days but as this article is going to be a new start so today Am going to write something learned through textbook since I was in school.

This gonna be a simple article.you may read it ful to know about our cells.

Not all cells are the same. There are structural differences between them as well as differences in shape and function. Depending on the structure of the nucleus.

In 1969, Loewy and Siekevitz called a cell an entity covered with a selectively permeable screen and a unit of biological activity that could replicate itself without any other living medium.

There are two types of cells,

• (i)Stem cells

• (ii)Actual cells.

Stem cells or Prokaryotic cells

Such cells do not have a well-formed nucleus. This is why they are also called stem nucleated cells. The nuclei of these cells are not covered by a membrane, so nucleo-objects are scattered throughout the cytoplasm. These cells do not have mitochondria, plastids, endoplasmic reticulum etc but ribosomes. The chromosome contains only DNA. Such cells are found in bluish green algae or bacteria.

Actual cells or Eukaryotic cells

The nuclei of these cells are well-organized, that is, the nucleus-objects are surrounded and well-organized by the nuclear membrane. These cells contain all the organs including ribosomes. Chromosomes contain DNA, proteins, histones and other elements. Most cells are like this.

There are two types of actual cells, body cells (somatic cells)and germ cells(Gametic cells), depending on the function.

• What is Somatic cells and germ cells?

Somatic cells: These cells participate in the formation of the body of multicellular organisms. In the process of mitosis, the body cells divide through division and thus the body grows. Body cells take part in the formation of various systems and organs.

Gametic cells : In sexual reproduction, germ cells are produced. In the process of miosis, the division of the germ cells takes place and the germ cells are produced. The number of chromosomes in the offspring germ cell is half that of the number of chromosomes in the maternal germ cell.Male and female gametes combine to form a new organism. This first cell formed as a result of the union of male and female gametes is called a zygote. Zygotes form organisms through repeated divisions.

While most of these organelles are in both plant and animal cells, there are some organelles that are found only in plant cells or only in animal cells. This time we will get acquainted with some cell organelles that can be seen under electron microscope.

Cell wall

The cell wall is one of the most important features of plant cells. It is made of dead or inanimate objects. Cells do not have cell walls. The chemical structure of the cell wall is quite complex, it contains chemicals called cellulose, hemicellulose, lignin, pectin, suberin. However, the bacterial cell wall is made up of proteins, lipids and polysaccharides, and the fungal cell wall is made up of chitin.

The primary cell wall is single-layered. A few types of chemicals secreted from the protoplasm accumulate on the middle screen, gradually forming a secondary wall.This wall sometimes has holes called wells. The cell wall strengthens the cell, maintaining the size and shape of the cell. Maintains contact with adjacent cells by creating plasmodesmata (microscopic ducts) and regulates the movement of water and mineral salts.

Protoplasm

The translucent, jelly-like substance inside the cell is called protoplasm. Cell membrane Everything surrounded by protoplasm, even the cell membrane itself is part of the protoplasm. In addition to the cytoplasm, there are cytoplasmic organs and nuclei..

Cell membrane (plasmalemma)

The two-layer elastic membrane outside the protoplasm is called the cell membrane or plasmalema. The fold of the cell membrane is called myclovi. It is mainly composed of lipids and proteins. As the cell membrane is a heterogeneous membrane, it regulates the movement of water and mineral salts through osmosis, as well as separating the cells from each other.

Pre-cytoplasm is the jelly-like substance that remains when the nucleus or nucleus is removed from the protoplasm. These cytoplasm contain many types of organelles. Although their work is different, they are dependent on each other. Some of these organs has membrane and some are membrane-free. Like👇

Mitochondria

This organ was discovered by Benda in 1898. It is surrounded by a two-layered coating or membrane. The inner layer is folded inwards. They are called cristae. Christie has round stalked objects called oxisomes. The enzymes are arranged in the oxyzyme. Inside the mitochondria is the matrix. The main function of the mitochondria is to assist in the respiration of the organism. You will see later that there are four stages of respiration; Glycolysis, Acetyl Co-A.

Since all the enzymes involved in the Krebs cycle are present in it, these reactions take place in the mitochondria. You see, the Krebs cycle produces the most energy. This is why mitochondria are called the ‘energy production center’ or ‘power house’ of the cell. This energy is expended by the organism in its various functions. Mitochondria are found in all plant cells and animal cells with few exceptions.

Nucleus

The nucleus is the most obvious object to be found in the protoplasm of a cell, carrying specific membrane chromosomes. Its shape is round, oval or cylindrical. Civic cells and red blood cells do not have a nucleus. The nucleus contains hereditary traits. It regulates all the metabolic functions in the cell. The lower parts are seen in the well-formed nucleus.

• Nuclear membrane

• Nucleoplasm

• Nucleolus

• Nuclear reticulam

• Nuclear pore

If I describe this all little organs and it's functions this article will be the longest article here. Btw, I have seen the longest article here with 87 minutes reading time written by scottishbussiness

There are many others organelles to describe but I don't want to bother you. Actually this kind of reading makes people bored I saw in my school. Even my friends didn’t like this Biology subject. But Biology was my most favourite subject. That's why I wanted to be a doctor.I tried to get admission to a medical college but I couldn’t reach the desired score.

By the way, If you are bothered am sorry for it. I just wrote this article just to start again.

Take care.

Reference : The article is based on a book I read at school. I wrote what I read at that time