Question

Объяснить механизм фотосинтеза

Answer 1

Благодаря фотосинтезу растение преобразует неорганический вещества в органические.Это происходит только в зелёных частях настения.Для фотосинтеза нужны:свет,вода,углекислый газ.

Answer 2

Mechanism of Photosynthesis

Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. This process occurs in the chloroplasts of plant cells and involves several key steps.

1. Light Absorption and Water Splitting: - In the first stage of photosynthesis, light energy is absorbed by chlorophyll and other pigments in the chloroplasts. This energy is used to split water molecules into oxygen, protons, and electrons.

2. Carbon Fixation: - The electrons produced from water splitting are used to power the process of carbon fixation, where carbon dioxide (CO2) from the atmosphere is combined with a five-carbon sugar molecule, ribulose-1,5-bisphosphate (RuBP), to form two molecules of 3-phosphoglycerate (3-PGA).

3. Reduction and Sugar Formation: - The 3-PGA molecules are then converted into glyceraldehyde-3-phosphate (G3P) through a series of reduction reactions, using ATP and NADPH generated in the light-dependent reactions. Some of the G3P molecules are used to regenerate RuBP, while others are used to produce glucose and other carbohydrates.

4. Light-Dependent Reactions: - The light-dependent reactions occur in the thylakoid membranes of the chloroplast and involve the conversion of light energy into chemical energy in the form of ATP and NADPH. These molecules are essential for the carbon fixation and reduction stages of photosynthesis.

5. Calvin Cycle: - The Calvin cycle, also known as the dark reactions or light-independent reactions, is the series of chemical reactions that occur in the stroma of the chloroplast and result in the production of glucose and other carbohydrates from CO2.

Photosynthesis Variants

There are different variants of photosynthesis, such as C3, C4, and CAM photosynthesis, which have evolved in response to different environmental conditions.

1. C3 Photosynthesis: - C3 plants, such as wheat and rice, use the conventional Calvin cycle for carbon fixation. However, they are less efficient in hot and dry conditions due to a tendency to lose water through transpiration.

2. C4 Photosynthesis: - C4 plants, like maize and sugarcane, have an additional step in carbon fixation that allows them to minimize water loss and thrive in high-temperature environments.

3. CAM Photosynthesis: - CAM plants, including cacti and succulents, open their stomata at night to minimize water loss and fix CO2 into organic acids, which are then used in the Calvin cycle during the day.

Conclusion

In summary, photosynthesis is a complex process that involves the conversion of light energy into chemical energy, the fixation of carbon dioxide, and the production of glucose and other carbohydrates. Different variants of photosynthesis have evolved to adapt to various environmental conditions, allowing plants to thrive in diverse habitats.

For visual representations of the photosynthesis process, you can refer to the following sources: 1. [Structure of a Typical Higher Plant Chloroplast Diagram](https://www.shutterstock.com/ru/image-vector/structure-typical-higherplant-chloroplast-diagram-749518939) 2. [Diagram of the Process of Photosynthesis](https://image.shutterstock.com/image-vector/diagram-process-photosynthesis-showing-light-600w-290826602.jpg)