Photosynthesis Basics & Empirical Equation — NEET Biology
📚 Practice ConceptBy the middle of the nineteenth century the key features of plant photosynthesis were known, namely, that plants could use light energy to make carbohydrates from CO₂ and water. The empirical equation representing the total process of photosynthesis for oxygen evolving organisms was then understood as:
Which of the following statements about the general process and components of photosynthesis are NOT correct? S1: The empirical equation for photosynthesis for oxygen evolving organisms represents water as the primary source of electrons and protons. S2: The overall process of photosynthesis is a single-step reaction that occurs uniformly throughout the chloroplast. S3: The main energy input for driving the synthesis of organic compounds in photosynthesis is chemical energy stored in ATP. S4: Chlorophyll 'a' is solely responsible for absorbing all wavelengths of light used in photosynthesis, while accessory pigments are not directly involved in light absorption. S5: The splitting of water is closely associated with Photosystem II and directly contributes to the accumulation of protons within the thylakoid lumen.
View solution & NCERT explanation
Correct answer: B — S2, S3 and S4 only
This question assesses the understanding of the fundamental aspects of photosynthesis, including its equation, energy source, and role of pigments. S1: This statement is correct. The overall equation 6CO2 + 12H2O → C6H12O6 + 6H2O + 6O2 shows 12 water molecules as reactants. "In green plants H2O is the hydrogen donor and is oxidised to O2." This also provides electrons for PSII. "Splitting of water is associated with the PS II; water is split into 2H+, [O] and electrons." S2: This statement is NOT correct. The NCERT states, "Note that this is not a single reaction but description of a multistep process called photosynthesis." Photosynthesis is divided into light reactions (in thylakoids) and dark reactions (in stroma). S3: This statement is NOT correct. "The green plants make or rather synthesise the food they need through photosynthesis and are therefore called autotrophs. Green plants carry out 'photosynthesis', a physico-chemical process by which they use light energy to drive the synthesis of organic compounds." The main energy input is light energy, which is then converted into chemical energy (ATP and NADPH). S4: This statement is NOT correct. While chlorophyll a is the chief pigment, accessory pigments like chlorophyll b, xanthophylls, and carotenoids also absorb light and transfer energy to chlorophyll a, thus broadening the range of light utilized for photosynthesis. "Indeed, they not only enable a wider range of wavelength of incoming light to be utilised for photosyntesis but also protect chlorophyll a from photo-oxidation." S5: This statement is correct. "The splitting of water molecule takes place on the inner side of the membrane, the protons or hydrogen ions that are produced by the splitting of water accumulate within the lumen of the thylakoids." This accumulation of protons helps establish the proton gradient for ATP synthesis. Therefore, statements S2, S3 and S4 are NOT correct.
What does NCERT say about By middle nineteenth century?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.