Chloroplasts-Food producer

We all like to live in a beautiful world. Plants contribute to make this world more beautiful. An enormous amount of plants is found in the world in many varieties. These plants have different colors, shapes etc.

 Most of the plants in the world are green. Also, there are other colors. The cell is the smallest living entity inside every living organism. So, these plants are made up of cells. They are called plant cells. The factor determining the color of the plants is in the plant cells. The green color of the leaves is determined by the chloroplast organelles of the plant cells.

Also, food production is mainly done by plants. The plant uses complex processes called photosynthesis to manufacture foods. Plant uses sunlight, water and carbon dioxide for this purpose. The pigments and enzymes in the chloroplast of the plant cells contribute to this.

The chloroplasts of the plant's cell is found in the cytoplasm. The amount of the cytoplasm varies in cell to cell. They are about 3 µm - 10 µm in diameter. Also, in light microscopes it is possible to see chloroplasts. But the electron microscope is used to study the structure of chloroplasts.

Structure of the chloroplast

Here describe, the structure of the chloroplast observed with an electron microscope. We have given a diagram of a chloroplasts. It accurately depicts the structure of the chloroplast.

 Like mitochondria, it also has two membranes, which are inner and outer membranes. This forms the chloroplast envelope. They always contain the green pigments chlorophyll, enzymes, electron carriers and other photosynthetic pigments. Those are located on a system of membranes. The system runs through a ground substance, or stroma. It consists set of flat, fluid filled, disc-liked sacs called thylakoids where the photosynthesis takes place. These thylakoids are arranged on top of one another, forming stacks called grana. They are interconnected by the membranes called lamellae. 

The stroma is gel-like, containing soluble enzymes, sugar and organic acids. Sometimes excess carbohydrate is seen stored as grains of starch. Also, lipid droplets are seen in chloroplasts. Chloroplasts also contain DNA, RNA, 70s ribosomes. 

What are the functions of the chloroplast?

We have mentioned lot of details about chloroplasts in the above of this article. It has many functions and in here we summarize the functions of chloroplasts. The main function of chloroplasts is to conduct photosynthesis. Photosynthesis is a biological process that captures light energy and transforms it into chemical energy as ATP and NADPH in the form of organic molecules such as carbohydrates, which is produced by carbon dioxide and water.

 Chloroplasts have some other functions which are fatty acids synthesis and amino acid synthesis. They have another interesting feature which is protein synthesizing machinery. Also, they contribute immune response in plants.

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Endoplasmic reticulum

Endoplasmic reticulum present in Eukaryotic cells. There are two types of endoplasmic reticulum found in Eukaryotic cells. They are

1. rough endoplasmic reticulum(rER) 
2. smooth endoplasmic reticulum(sER)

They cannot be examined with a light microscope.If we look through an electron microscope we can see the system of membranes running through the cytoplasm of Eukaryotic cell.

 Endoplasmic reticulum shown as a network or reticulum of membranes. We have given a diagram of endoplasmic reticulum and you can obtain some idea about it.

There is a prominent nucleus of the Eukaryotic cells. The nucleus consists of different kind of structures. We will explain about nucleus later.

 We have shown nuclear envelope in the diagram.Because, we can't describe endoplasmic reticulum without mentioning nuclear envelope.Endoplasmic reticulum continues with the nuclear envelope according to the diagram below. It appears as pairs of parallel lines (membranes) running through the cytoplasm . 

In here we have shown two-dimensional of the endoplasmic reticulum. Thus, you can see the surface of the endoplasmic reticulum. The endoplasmic reticulum is composed of multi layers imagined as sheets in three-dimensional perspective. It is usually sheet-like structure rather than tubular.

There is a structure called cisternae found in the endoplasmic reticulum. The cisternae are flattened membrane bound sacs. 

Also, you can see dots like views on the membranes of Endoplasmic Reticulum as shown in diagram. Those are ribosomes. The cisternae covered with ribosomes forming rough endoplasmic reticulum. Sometimes ribosomes are not present in endoplasmic reticulum called smooth endoplasmic reticulum. 

Smooth endoplasmic reticulum have tubular like structure rather than rough endoplasmic reticulum.

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Mitochondria

Mitochondria appear in the eukaryotic cells and referred to as cellular energy centre. 

The major sites  of aerobics respiration within cells. The number of mitochondria in the cell varies significantly from cell to cell. Also, the number of mitochondria in a cell depends on the nature of the cell and the type of the organism.

In cells with high energy requirement, the mitochondria are abundant. There is a higher number of mitochondria in liver cells because of the high energy requirement.

In low-energy cells, the number of mitochondria decreases.

Also, the shape and size of the mitochondria are different.

Generally, the active cells are larger than  less active cells.

Mitochondria has the ability to change its shape. Some mitochondria can move to active areas of cells to supply energy. The movement of mitochondria is prevalent in the large concentration of mitochondria in areas where ATP greater.

Structure of mitochondria

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Cytoplasm

The living contents of Eukaryotic cells are divided into nucleus and cytoplasm. The cytoplasm and nuclei together forms into the Protoplasm.

Cytoplasm is an aqueous substance. It contains variety of cell organelles such as mitochondria, ribosomes, endoplasmic reticulum, chloroplast etc. And also contain insoluble waste storage products etc.

The soluble part of the cytoplasm forms the ground substance between cell organelles. It contains a skeleton of fibrous but otherwise appear and structureless in the electron microscope.

It consists of 90% water and forms solution. Solution contains all the fundamental biochemical of life.

Some of these are ions, small molecules and large molecules.

Sodium, Potassium are some examples for ions in cytoplasm.

Salts, sugars, amino acids, fatty acids, nucleotides, vitamins and dissolved gases are examples for small molecules in cytoplasm.

Also proteins are large molecules finding inside the cytoplasm which form colloidal solution.

According to this explanation ground substance is acting as a store of vital chemicals.

Also, it is the site of certain metabolic Pathways.

                 Ex:- glycolysis

Some organelles move inside the cytoplasm such as mitochondria move about.

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