Chloroplast Structure and Function
Chloroplast is the most important organelle in any plant cell. Let us take a look at chloroplast structure and function.
We might not be aware of the number of cell organelles that make up a cell, unless you are a biology student, of course. But I guess most of us are familiar with the term 'cell', a biological cell that regulates the body metabolism in a manner which helps smooth functioning. Now, as is in animal cells, the same is the case for plant cells, wherein the cells regulate the plant metabolism, the nutrient flow (food and water), carbohydrate production, etc. What distinguishes a plant cell function structure from an animal cell is a peculiar organelle present in the former, chloroplast.
Have you ever wondered why plants appear green in color? If you know, then you must be knowing the reason as well, however, for those who are wondering, it is mainly because of the pigment chlorophyll present in the cells which is green in color. According to physics laws, when the sunrays fall on the leaves, they absorb all the light colors of the visible spectrum and reflect green color alone due to which they appear green. Now, this holds true for almost all plants, however there are few plants which have other pigments and appear to be of that particular color.
When I said that plants absorb light, another relative term comes into picture, that is photosynthesis. This is a unique process which takes place in plant cells alone. It involves the absorption of light and carbon dioxide to make food that is in the form of complex carbohydrates like glucose.
Structure
If you happen to check the plant cell anatomy under a microscope, you will see a number of chloroplasts scattered here and there in the cell. Chloroplasts are oval in shape, of the size of 2 to 10 micrometers in diameter, and 1 micrometer thick and restricted by cell membranes, the outer cell membrane and the inner cell membrane. The space between these two is called the inter membrane space and helps give a definite shape to these organelles. The inner structure is pretty complex and largely consists of two parts, the stroma and the grana. Stroma is the aqueous fluid present with the chloroplasts, comparable to the cytosol of a cell. This is the key site wherein dark reaction of photosynthesis occurs. Grana, on the other hand, are present in the form of thylakoids arranged in bundles and appear as discs under the microscope. These are connected to each other with the aid of intergranal lamellae. This is the primary site for the light reaction of photosynthesis. Let's see how these function.
Functions
As I mentioned, the chloroplast function is related to photosynthesis. The thylakoids are made up of photo systems, chlorophyll and accessory pigments which absorb light resulting in electron transfer to form complex co factors like NADP (Nicotine Amide Dinucleotide Phosphate) and ATP (Adenosine Triphosphate) which are energy providing molecules. This is followed by the dark reaction wherein carbon fixation and carbohydrate formation takes place using ATP and NADP. This reaction takes place in the stroma and is named as the Calvin cycle, after the discoverer.
Have you ever wondered why plants appear green in color? If you know, then you must be knowing the reason as well, however, for those who are wondering, it is mainly because of the pigment chlorophyll present in the cells which is green in color. According to physics laws, when the sunrays fall on the leaves, they absorb all the light colors of the visible spectrum and reflect green color alone due to which they appear green. Now, this holds true for almost all plants, however there are few plants which have other pigments and appear to be of that particular color.
When I said that plants absorb light, another relative term comes into picture, that is photosynthesis. This is a unique process which takes place in plant cells alone. It involves the absorption of light and carbon dioxide to make food that is in the form of complex carbohydrates like glucose.
Structure
If you happen to check the plant cell anatomy under a microscope, you will see a number of chloroplasts scattered here and there in the cell. Chloroplasts are oval in shape, of the size of 2 to 10 micrometers in diameter, and 1 micrometer thick and restricted by cell membranes, the outer cell membrane and the inner cell membrane. The space between these two is called the inter membrane space and helps give a definite shape to these organelles. The inner structure is pretty complex and largely consists of two parts, the stroma and the grana. Stroma is the aqueous fluid present with the chloroplasts, comparable to the cytosol of a cell. This is the key site wherein dark reaction of photosynthesis occurs. Grana, on the other hand, are present in the form of thylakoids arranged in bundles and appear as discs under the microscope. These are connected to each other with the aid of intergranal lamellae. This is the primary site for the light reaction of photosynthesis. Let's see how these function.
Functions
As I mentioned, the chloroplast function is related to photosynthesis. The thylakoids are made up of photo systems, chlorophyll and accessory pigments which absorb light resulting in electron transfer to form complex co factors like NADP (Nicotine Amide Dinucleotide Phosphate) and ATP (Adenosine Triphosphate) which are energy providing molecules. This is followed by the dark reaction wherein carbon fixation and carbohydrate formation takes place using ATP and NADP. This reaction takes place in the stroma and is named as the Calvin cycle, after the discoverer.
Like This Article?
Follow:
Post Comment | View Comments