Photosynthesis in Plants

Photosynthesis is an endothermic process (option B). Photosynthesis absorbs energy from sunlight to convert carbon dioxide and water into glucose and oxygen. Endothermic processes require energy input, whereas exothermic processes release energy. 'Neutral process' and 'thermostatic process' are not standard thermodynamic classifications.

Photosynthesis converts light energy (sunlight) into chemical energy stored in glucose molecules. This occurs in chloroplasts containing chlorophyll, which captures light energy to drive the synthesis of organic compounds from CO2 and water.

RuBP (Ribulose-1,5-bisphosphate) is the first compound to accept CO2 in the Calvin cycle (dark phase of photosynthesis). This reaction is catalyzed by RuBisCO enzyme. NADP and Ferredoxin are involved in electron transport, while Cytochrome is part of electron transport chain.

Chlorophyll 'a' has the molecular formula C55H72O5N4Mg, containing a porphyrin ring with a magnesium atom at the center. Chlorophyll 'b' differs by having one more oxygen atom (C55H70O6N4Mg). The key difference is the substitution of a formyl group (-CHO) for the methyl group (-CH3) on the porphyrin ring.

Free energy is converted into potential energy and stored.

They are the food producers of the cell and they work to convert light energy of the sun into sugars that can be used by cells.

This is true as enzymes needed for the fixation of carbohydrates are not present in the above set up.

All of the above four statements are the true characteristics of cyclic photophosphorylation.

It is the final electron acceptor during light reaction and is converted to its reduced form NADPH₂.

Chlorophyll-a is found in all groups of algae and is the universal photosynthetic pigment. It's the primary reaction center pigment in all photosynthetic organisms. Chlorophyll-b is found in green algae and plants, chlorophyll-c in diatoms and brown algae, and chlorophyll-d in some red algae - but only chlorophyll-a is truly universal across all algal groups.

In CAM (Crassulacean Acid Metabolism) plants, phosphoenol pyruvic acid (PEP) is the primary CO2 acceptor. During the night, PEP carboxylase fixes CO2 into oxaloacetate (which is converted to malate). During the day, malate releases CO2 for the Calvin cycle. Phosphoenol pyruvate is the 3-carbon compound that accepts CO2, not ribulose biphosphate (RuBP - used in C3 and C4 plants) or the other options listed.

The absorption spectrum of chlorophyll is useful in identifying the green colour pigment of chlorophyll. It approximates the action spectrum of photosynthesis. It also shows that some colours of light are absorbed more than others

Quantasome is the globular particle seen within the thylakoid membrane carrying out photochemical reaction during photosynthesis. Each quantasome is composed of about 200 to 300 chlorophyll molecules.

Blackman (1905) discovered that photosynthesis consists of two distinct phases: the light reactions and the dark reactions. The dark reactions (light-independent reactions) don't directly require light but use the products of light reactions. Calvin later elucidated the specific pathway (Calvin cycle) of the dark reaction.

During tomato ripening, chloroplasts (which contain green chlorophyll) break down and disappear. Simultaneously, chromoplasts (plastids containing red pigments like lycopene) develop and become visible. This transformation from chloroplasts to chromoplasts causes the color change from green to red.