Conversion of light energy to chemical energy. Reactions of photosynthesis, where they take place, and their ecological importance.
Okay, if the light dependent reactions can create the ATP itself, then why not just transport that ATP everywhere instead of forming Glucose then spending a lot of other time in transforming back that Glucose into ATP? • (33 votes) Excellent question. The major reasons that I know of: (61 votes) what is hydrolysis • (17 votes) When you add water, you can separate a compound into two. For example in hydrolysis of an ester, when you add water you get alcohol and carboxylic acid. (19 votes) Why is the first photosystem depicted in photosynthesis diagrams called "photosystem II" and the second photosystem called "photosystem I"? Are the names arbitrary or do they tell us something about the nature of how the photosystems work? • (8 votes) The reason for this is simply because Photosystem I was discovered first, and Photosystem II was discovered second. You're right, it is confusing because the Photosystem II process occurs first, followed by Photosystem I. (27 votes) Why would you consider photosynthesis important ? • (0 votes) Photosynthesis is extremely important! It is the process in plants that allows it to harness energy from sunlight and convert it into chemical energy that can be used by plants and other organisms. In fact all the energy we get from food is derived from the energy we get directly from plants or indirectly from animals that ate plants. Hence without the sun or plant's ability to carry out photosynthesis, there would be no energy to sustain most of the life on earth. (29 votes) The reactions occur without any dependence on light...so can it run during night time?...if so,in night time, the guard cells of the stomata close, so how can it take in carbon-dioxide to continue the cycle?... • (4 votes) 7 years ago Posted 7 years ago. Direct link to Marianne's post “Both reactions, the light...” Both reactions, the light-depended reaction and the Calvin's cycle OCCURS ONLY in the light (and out of color spectrum, mainly blue and red colors are used thus green reflected into your eye). (5 votes) Wait, so:ATP=Three Phosphates. ADP=Two Phosphates. What if there is only one Phosphate? • (0 votes) ATP is Adenosine TriPhosphate, with three phosphates, and lots of energy stored in bonds. (11 votes) In our school, we are doing an experiment where the rate of photosynthesis is being measured using different coloured waters. We mixed blue, red and green food colouring with water and then light was shone on them including clear water. Elodea plant was used. The data measured using an oxygen probe shows that the plant in clear water produces oxygen faster and green comes in second but blue and red produces oxygen slower. Why is that? Shouldn't red produce oxygen faster as red has the highest wavelength among other colour? Why does clear water produce oxygen fastest and why does green produce oxygen faster even though the colour of the plant is green? • (1 vote) It is likely that your colored water is not purely filtering those individual wavelengths. As such, the green water is still allowing some blue and red wavelengths to pass, while the blue and red water is isolating more to only their ends of the spectrum. Since green still allows some of both blue and red to pass, chlorophyll from both ends of the spectrum still reacts with light and thus you have production on both ends. Whereas, with the blue or red water, primarily only the chlorophyll associated with those individual spectra can react. For a rough illustration, if you assume the light curves below and chlorophyll A absorbs blue light and chlorophyll B absorbs red. For the green curve, A and B get about 50% light. For the blue curve, the A is getting about 75% light and B is getting 0%, and vice versa for Red curve. So green is getting a weighted average of 50% reaction rate while Blue or Red get about 37.5% reaction rate. (6 votes) What happens after the plants form glucose and oxygen? What happens to the oxygen when it is released? • (3 votes) Glucose is utilised in respiration and excess glucose is stored in the form of starch.... (3 votes) What does the Pi stand for in the pictures describing light reactions and the Calvin cycle? • (2 votes) Pi stands for inorganic Phosphate... It is described in chemistry as the phosphoryl group, i.e. PO3 with a 2- charge.... This phosphate bonds with the adenosine group to form AMP, ADP, ATP, and the like. Hope this helps (3 votes) do all other biological molecules are derived from carbs. • (4 votes) Good question! The answer is yes. Plants make sugars through photosynthesis, but then convert some of that sugar into lipids and amino acids. (1 vote)Want to join the conversation?
1) The high energy bonds in ATP are (by definition) unstable, so for long term storage of energy ATP is not a good choice.
2) In many situations phosphate is a limiting nutrient, so needing to make more ATP could severely limit the plants ability to store energy.
3) Fixed carbon (e.g. glucose) can be converted into other molecules the plant needs including:
• cellulose for structure
• lipids for long term energy storage, cell membranes, etc.
• proteins for structure, catalysis, etc.
1. Light-depended reaction gives you the NADPH
2. You need NADPH in Calvin's cycle
And you don't get the NADPH without light.
EDIT after a comment brought up by Safwan: to be exact, The Calvin cycle needs light to start, but can continue for a while even without the light.
What would it be called? And what would happen if there was only one phosphate?
ADP is Adenosine DiPhosphate, with two phosphates, and some energy stored in bonds.
AMP is Adenosine MonoPhosphate, with a single phosphate group. These do not have energy stored in the bonds between phosphates, as there is only one.
Biological processes add/subtract phosphates, changing these into each other.
A related molecule, cAMP (cyclic AMP), has a cyclic structure, and rather than an energy storage role, it functions as a messenger in cell signaling pathways.
| A - B |- A B |A B-
| / \ | \ | /
| / \ | \ | /
|/ \ | \ | /
Green Blue Red
The o2 released might be utilised by humans etc
https://www.bbc.com/education/guides/z23ggk7/revision/4
As an expert in the field of photosynthesis and the conversion of light energy to chemical energy, it's evident that the questions and discussions in the provided article touch upon several key concepts related to this biological process. My expertise allows me to provide a comprehensive overview of these concepts and address the queries raised by the participants in the conversation.
Firstly, the primary process involved in the conversion of light energy to chemical energy is photosynthesis. This intricate biological process occurs in the chloroplasts of plant cells, where light energy is captured by chlorophyll molecules. The captured light energy is then utilized to drive the synthesis of organic molecules, primarily glucose, from carbon dioxide and water. The overall reaction for photosynthesis can be summarized as:
[6 \text{CO}_2 + 6 \text{H}_2\text{O} + \text{light energy} \rightarrow \text{C}6\text{H}{12}\text{O}_6 + 6 \text{O}_2]
The process of photosynthesis comprises two main stages: the light-dependent reactions and the Calvin cycle (light-independent reactions).
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Light-Dependent Reactions:
- These reactions take place in the thylakoid membrane of the chloroplasts.
- Light energy is used to generate ATP (adenosine triphosphate) and NADPH (nicotinamide adenine dinucleotide phosphate), which are energy-rich molecules.
- The energy from these molecules is later utilized in the Calvin cycle.
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Calvin Cycle (Light-Independent Reactions):
- This phase occurs in the stroma of the chloroplasts.
- ATP and NADPH produced in the light-dependent reactions are used to convert carbon dioxide into glucose through a series of chemical reactions.
Now, addressing the question raised by Paarth Tara regarding the transportation of ATP instead of forming glucose: The high-energy bonds in ATP are unstable, making it unsuitable for long-term energy storage. Additionally, the formation of glucose allows plants to store energy in a more stable form. Glucose serves as a versatile molecule that can be converted into other essential compounds such as cellulose, lipids, and proteins, fulfilling various structural and metabolic needs of the plant.
Furthermore, the conversation delves into related topics such as hydrolysis, the naming of photosystems (Photosystem I and Photosystem II), the importance of photosynthesis in sustaining life on Earth, and the occurrence of photosynthetic reactions with and without light.
The questions raised by participants regarding hydrolysis, the nature of photosystems, and the role of light in the Calvin cycle demonstrate a curiosity about the underlying biochemical mechanisms. These queries have been effectively addressed, shedding light on the scientific principles governing photosynthesis.
In conclusion, the provided article and the ensuing conversation explore fundamental concepts related to the conversion of light energy to chemical energy in photosynthesis. My expertise allows me to navigate through these concepts, providing a coherent and informative overview for those seeking a deeper understanding of this crucial biological process.
