Photosynthesis In Higher Plants

To solve this question, we need to identify which organism among the given options does not produce oxygen during photosynthesis. Let's analyze the options:

1. Chara: Chara is a genus of green algae, and like most green plants, they perform oxygenic photosynthesis, which involves the release of oxygen. Therefore, Chara does produce oxygen during photosynthesis.
2. Green sulphur bacteria: These are a group of photosynthetic bacteria that perform anoxygenic photosynthesis. Instead of using water as an electron donor (as in oxygenic photosynthesis), they use other compounds like hydrogen sulfide (H₂S) and do not release oxygen as a by-product. This makes them different from typical photosynthetic organisms like plants and algae.
3. Cycas: Cycas is a genus of gymnosperm, which performs oxygenic photosynthesis and releases oxygen as a by-product.
4. Nostoc: Nostoc is a genus of cyanobacteria, commonly known as blue-green algae, and it performs oxygenic photosynthesis, producing oxygen as a by-product.

Based on this analysis, the organism that does not produce oxygen during photosynthesis is green sulphur bacteria.

Conclusion: The correct answer is Green sulphur bacteria.

In photosynthesis, the light reaction (also known as the photochemical phase) takes place in the thylakoid membranes of the chloroplasts. During this process, light energy is captured and converted into chemical energy, resulting in the formation of certain products. Let's break down the options given and determine which of them is not a product of the light reaction:

1. ATP (Adenosine Triphosphate): During the light reaction, ATP is synthesized from ADP and inorganic phosphate through a process known as photophosphorylation. ATP acts as an energy carrier.
2. NADPH (Nicotinamide Adenine Dinucleotide Phosphate): NADP⁺ is reduced to NADPH, which serves as a reducing agent and is used in the Calvin cycle (light-independent reactions) for the synthesis of glucose.
3. Oxygen: Oxygen is produced as a by-product when water molecules are split by photolysis (light-induced water splitting). This process releases oxygen gas into the atmosphere.
4. NADH: This is a reducing agent that is typically involved in cellular respiration. It is not produced during the light reaction of photosynthesis.

Therefore, among the given options, NADH is not a product of the light reaction of photosynthesis.

To summarize, the primary products of the light reactions are ATP, NADPH, and Oxygen. The correct answer is NADH as it is associated with mitochondrial electron transport during cellular respiration, not photosynthesis.

The question asks which of the given organisms does not produce oxygen during photosynthesis. To answer this question, we need to understand the process of photosynthesis and how it varies among different groups of organisms. Let's analyze each option one by one:

1. Green Sulphur Bacteria: These bacteria perform a type of photosynthesis that does not produce oxygen. They use hydrogen sulfide (H₂S) instead of water as an electron donor, resulting in the production of sulfur instead of oxygen. This process is called anoxygenic photosynthesis.
2. Cycas: Cycas is a genus of seed plants. Similar to most land plants, Cycas performs oxygenic photosynthesis, where water is used as an electron donor, and oxygen is released as a byproduct.
3. Nostoc: Nostoc is a genus of cyanobacteria. Cyanobacteria are known for carrying out oxygenic photosynthesis, where oxygen is produced as a byproduct.
4. Chara: Chara is a genus of green algae. Like other green plants, Chara also performs oxygenic photosynthesis, releasing oxygen.

Based on the above explanation, the correct answer is that oxygen is not produced during photosynthesis by green sulphur bacteria. The other listed organisms, including Cycas, Nostoc, and Chara, perform oxygenic photosynthesis, which results in the production of oxygen.

To determine which statement is incorrect, let's examine the provided options one by one:

1. Oxidation-reduction reactions produce proton gradient in respiration: This statement is correct. In cellular respiration, oxidation-reduction (redox) reactions within the Electron Transport Chain (ETC) lead to the pumping of protons (H⁺) across the inner mitochondrial membrane, creating a proton gradient. This proton gradient is essential for ATP synthesis during oxidative phosphorylation.
2. During aerobic respiration, the role of oxygen is limited to the terminal stage: This statement is correct. In aerobic respiration, oxygen acts as the final electron acceptor at the end of the ETC. It combines with electrons and protons to form water, completing the process of cellular respiration.
3. In ETC (Electron Transport Chain), one molecule of NADH+H⁺ gives rise to 2 ATP molecules, and one FADH₂ gives rise to 3 ATP molecules: This statement is incorrect. The standard biochemical perspective states that one molecule of NADH typically yields approximately 2.5 to 3 ATP molecules, while one FADH₂ yields approximately 1.5 to 2 ATP molecules. Therefore, the values in this statement are incorrect.
4. ATP is synthesized through complex V: This statement is correct. Complex V, also known as ATP synthase, is the enzyme responsible for synthesizing ATP as protons flow back through it, driven by the proton gradient established during earlier stages of the ETC.

Based on these analyses, the incorrect statement is: "In ETC (Electron Transport Chain), one molecule of NADH+H⁺ gives rise to 2 ATP molecules, and one FADH₂ gives rise to 3 ATP molecules." The expected ATP yield is different as described.

To determine which statement is incorrect, let's analyze each option based on photosynthesis concepts:

1. Cyclic photophosphorylation involves both PS I and PS II.
   • Analysis: Cyclic photophosphorylation involves only photosystem I (PS I). It does not involve photosystem II (PS II). In cyclic photophosphorylation, electrons are cycled back to PS I, and only ATP is produced, not NADPH.
   • Conclusion: This statement is incorrect because PS II is not involved in cyclic photophosphorylation.
2. Both ATP and NADPH+H⁺ are synthesized during non-cyclic photophosphorylation.
   • Analysis: Non-cyclic photophosphorylation involves both PS I and PS II and leads to the production of ATP and NADPH. Electrons are transferred from water to NADP⁺, synthesizing NADPH along with ATP generation through photophosphorylation.
   • Conclusion: This statement is correct.
3. Stroma lamellae have PS I only and lack NADP reductase.
   • Analysis: Stroma lamellae contain PS I but not PS II, aligning with their role in cyclic photophosphorylation, and they do lack NADP reductase, which is part of the non-cyclic electron transport chain.
   • Conclusion: This statement is correct.
4. Grana lamellae have both PS I and PS II.
   • Analysis: Grana lamellae have both PS I and PS II. These structures are responsible for non-cyclic photophosphorylation, which involves both photosystems to generate ATP and NADPH.
   • Conclusion: This statement is correct.

After evaluating the options, it is clear that the incorrect statement is: "Cyclic photophosphorylation involves both PS I and PS II."