Thursday, September 21, 2017

Chloroplasts-Food producer

photosynthesis
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

structure of the chloroplasts

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.


Monday, September 11, 2017

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.