Profile
Settings
Refer your friends
Sign out
Introduction
When doing a photosynthesis experiment, it may be observed that light intensity has a significant impact on the rate of photosynthesis. Xanthophyll, chlorophyll a, chlorophyll b and carotene are the only photosynthetic pigments that can be found in chloroplasts, according to the photosynthesis criteria. Photosynthesis is a process in which carbon dioxide, water, and light from the sun are used by all green plants and a few other autotrophic organisms. In order to create nutrients, this is done. This produces oxygen as a by-product.
To better understand photosynthesis, let us take a closer look at it.
Photosynthesis
Phs (pronounced “fos”) and σύνθεσις (pronounced “synthesis” in Greek) are the origins of the term “photosynthesis.”
The Greek word for “light” is phs, while the Greek word for “combining together” is σύνθεσις. This refers to “light-aided synthesis.”
Plants are not the only species capable of photosynthesis. purple bacteria, green sulphur bacteria, and cyanobacteria are examples of prokaryotes that can do photosynthesis in the same way as plants. Photosynthesis produces glucose, which is then used for a variety of cellular functions. This physio-chemical process produces oxygen as a by-product.
Algae also use photosynthesis to turn sunlight into chemical energy. As a by-product of photosynthesis, oxygen is released, and light is regarded as a key element in the process.
When plants employ light energy to convert carbon dioxide and water into glucose and oxygen, they are referred to as phototrophs. Chloroplasts are small cellular organelles that are found in the leaves.
Chlorophyll is a green pigment found in chloroplasts. Chlorophyll molecules take in light energy, while stomata in the leaves’ epidermis allow carbon dioxide and oxygen to enter.
In addition to oxygen, carbohydrates such as glucose and fructose are produced as a by-product of photosynthesis.
Across the plant, sugar can be found in everything from the roots to the leaves to its flowers to its seeds. In other words, the plants utilise these sugars as a source of energy, which helps them develop. Carbohydrates like starch and cellulose are formed when they combine with each other. Cellulosic substance, or cellulose, is found in the cell walls of plants. In plants and blue-green algae, chloroplasts are the places where photosynthesis takes place. Chloroplasts – green plastids – are found in all green portions of a plant, including the stems, leaves, and sepals — floral components. The mesophyll cells of leaves include several cell organelles, which are unique to plant cells.
Factors influencing Photosynthesis
Photosynthesis is accelerated by an increase in light intensity. Low light intensity, on the other hand, leads in a reduced photosynthetic rate
The amount of carbon dioxide in the air: Photosynthesis can be accelerated by raising the concentration of carbon dioxide in the atmosphere. Photosynthesis typically requires carbon dioxide concentrations between 300 and 400 parts per million (PPM).
Plants need temperatures between 25° and 35° C in order to perform photosynthesis efficiently.
Water: Deficiency of water in photosynthesis can lead to issues with the absorption of carbon dioxide, as water is a crucial element in photosynthesis. The lack of water causes stomatal openings to refuse to keep the amount of water they have stored inside.
The leaf surface may be contaminated by industrial pollution and other particles. This can obstruct the stomata’s pores, making it difficult for plants to take in CO².
Equation of Photosynthesis
Carbohydrates and water are both necessary components of the photosynthesis process. Oxygen and glucose are the two products that result from the reaction of these two ingredients. Photosynthesis is therefore classified as an endothermic process.
The photosynthesis formula is as follows:
6CO2 + 6H2O —> C6H12O6 + 6O2
While plants produce oxygen as a by-product of photosynthesis, some bacteria do not. Anoxygenic photosynthetic bacteria refer to these organisms. Oxygenic photosynthetic bacteria are those that create oxygen as a by-product of photosynthesis.
Organic Pigments with Photosynthetic Capabilities
It is common for leaves to include four distinct types of pigments:
Carotenoids
Chlorophyll a
Xanthophylls
Chlorophyll b
Chlorophyll’s Molecular Structure
Chlorophyll is made up of four nitrogen atoms surrounding a magnesium atom in its structure. In addition, there is a hydrocarbon tail. Compared to chlorophyll-a, chlorophyll-f is more effective in absorbing near-infrared rays.
It is located in the chloroplasts of the plant cell and in the cyanobacterial mesosome. This green colour pigment is essential to photosynthesis because it allows plants to take up sunlight’s energy. It is a combination of chlorophyll a and b that is used in plants as chlorophyll . These other types of chlorophyll, including chlorophyll-f , chlorophyll-d, chlorophyll-c1 and chlorophyll-c2, are also found in other organisms that undertake photosynthesis.
Process Of Photosynthesis
Chloroplasts are cell organelles that perform photosynthesis at the cellular level. It is a green pigment called chlorophyll that gives the leaves their distinctive green hue.
The petiole, epidermis, and lamina of a leaf are all structural components. During photosynthesis, the lamina absorbs sunlight and carbon dioxide.
Steps in photosynthesis
Photosynthesis involves the exchange of carbon dioxide and water, which is delivered to the leaves via the xylem vessels by the root hairs. Water molecules are split into hydrogen and oxygen by chlorophyll, which uses sunlight to do so.
In the creation of glucose, water molecules and carbon dioxide from the air are utilised. Additionally, the leaves release oxygen into the atmosphere as a waste product.
There are two ways plants obtain glucose: by feeding themselves and by storing it as glycogen in their roots, leaves, and fruits.
Photosynthesis also relies on the presence of pigments, which are essential biological components. T give colour and absorb light at a particular wavelength and reflect it back. Chlorophyll a, chlorophyll b, and carotenoids are found in the thylakoids of chloroplasts in all green plants . To capture light energy is its primary function
There is a lot of chlorophyll-a in the plant.
Photosynthesis is a two-step process:
Reactions that require light or are light-dependent
Reaction that is not influenced by light
The two phases of photosynthesis in plants are depicted in this diagram.
Reactions that require light or are light-dependent
The light reaction is the first step of photosynthesis, and it only occurs during the day when the plant is exposed to sunlight. The light-dependent reaction occurs in the chloroplasts’ thylakoid membranes.
Photosystems are the membrane-bound sac-like structures inside the thylakoid that act by capturing light and are known as Grana.
Plant cells include enormous complexes of pigment and protein molecules, which play a key part in the light reactions of photosynthesis..
Photosystem I and photosystem II are the two types of photosystems.
The light energy is transformed into ATP and NADPH, which are used in the second phase of photosynthesis, under the light-dependent processes.
In the light processes, two electron-transport chains generate ATP and NADPH, while water is utilised and oxygen is produced, respectively.
Reaction that is not influenced by light
Carbon-fixing reaction is another name for the dark reaction.
Water and carbon dioxide molecules are combined to generate sugar molecules without the need for light.
The dark reaction occurs in the chloroplast stroma, where the NADPH and ATP products of the light reaction are used.
Stomata allow plants to take in carbon dioxide from the air and begin the Calvin photosynthesis cycle.
One glucose molecule can be made from six carbon dioxide molecules by using the ATP and NADPH generated during the light reaction.
It is possible to simplify the chemical equation for the dark reaction to:
5H2O + 6 NADPH + 3CO2 + 9ATP → 2H + G3P + 9 ADP + 6 NADP + 8 Pi
* G3P – glyceraldehyde-3-phosphate
Photosynthesis’s significance
All life on earth depends on photosynthesis for its survival. Plants use this technique to generate their own nutrients and hence function as primary producers in the food chain.
Additionally, photosynthesis produces oxygen, which is essential for the existence of most creatures.
Conclusion
For photosynthesis to occur, carbon dioxide is required. The half of the leaf within the glass container did not get carbon dioxide, but both halves of the leaf got the same quantity of water, chloroplasts and sunshine.
