Test: Cyclic and Non-Cyclic Photo-Phosphorylation Calvin Cycle (June 20) - NEET MCQ

Carbonation is the addition of carbon dioxide to an acceptor. Photosynthetic carboxylation requires ribulose-1, 5-biphosphate or RuBP as acceptor of carbon dioxide and RuBP- Carboxylase oxygenase as enzyme in C₃ plants In C₄ plants, initial fixation of CO₂ occurs in mesophyll cells, The primary accept or of CO₂ is phosphoenol pyruvate which combines with CO₂ in presence of PEP carboxylase to form oxaloacetic acid or oxaloacetate. So, the correct answer is 'RuBP carboxylase and PEP carboxylase'.

In C₃ cycle for the fixation of every carbon dioxide molecule, the reduction and regeneration of steps require around 3ATP & 2 NADPH2 molecules.
So, the correct option is '3 ATP and 2NADPH₂'.

In fixation, the first stage of the Calvin cycle, light-independent reactions are initiated; CO₂ is fixed from an inorganic to an organic molecule. In the second stage, ATP and NADPH are used to reduce 3-PGA into G3P; then ATP and NADPH are converted to ADP and NADP⁺, respectively.

Melvin Calvin, a biochemist who detected the crucial phase of photosynthesis that now bears his name and won him a Nobel Prize in 1961, died on Wednesday at Alta Bates Hospital in Berkeley, Calif. He was 85.
So, the correct option is 'Calvin'.

The process by which ATP is sysnthesised by cells in mitochondria and chloroplasta is named as phosphorylation. Photophosphorylation is the synthesis of ATP from ADP and inorganic phosphate (Pi) in the presence of light, inside chloroplast. Photosphosphorylation is of two main types-Cyclic and non-cyclic photophosphorylation.

During Z- scheme, the electron extrucded by PS I passes through special chlorophyll X, Fe-S, ferredoxin, to finally reach NADP+,NADP⁺ is ultimately reduced by combining with H⁺ (released during photolysis) with the help of NADP⁺ reductase enzyme.

PSI is involved in both cyclic and non-cyclic photophosphorylation PS II is involved only in non-cyclic photophosphorylation PS II is present in the aprressed (inner) part of grana thylakoids, PS I is located in the non-appressed (outer) part of grana thylakoids as well as stroma thylakoids

Non-cydic photophosphorylation is the normal process of photophosphorylation in which the electron expelled by the excited photocentre does not return to it. Non- cydic photophosphorylation is carried out in collaboration of both photosystems I and II. Electron released during photolysis of H₂O is picked up by photocentre of PSII called P₆₈₀. The same is extruded out when the photocentre absorbs light energy (hv). Electrons released during the photolysis of water are immediately accepted by oxidised reaction centre of PSII (i.e., P₆₈₀) through an unknown substance Z.

Chemiosmosis is the movement of ions across a semipermeable membrane, down their electrochemical gradient.
A represents the thylakoid lumen, b-F_o & c-F₁.

In cyclic photophosphorylation, an electron expelled by the excited photocentre (P₇₀₀) is returned to it after passing through a series of electron carriers. Its photocentre P₇₀₀ extrudes an electron with a gain of 23kcal/mole of energy after absorbing a photon of light (hv). After losing the electron the photocentre becomes oxidised. The expelled electron passes through a series of carriers including X or A₀ (a special P₇₀₀ chlorophyll molecule), A₁, (a quinone), FeS complexes (F_eS_x,F_eS_A,F_eS_B), ferredoxin (Fd), plastoquinone (PQ), cytochrome b−f complex and plastocyanin (PC) before returning to photocentre. While over the cytochrome complex, the electron energises passage of protons to create a proton gradient for synthesis of ATP form ADP and inorganic phosphate.