Photosynthesis in Higher Plants Test - 79

NADP$$^+$$ accepts protons from photolysis of water and is reduced to NADPH$$_2$$, which is transferred or used to reduce CO$$_2$$ during the light independent reaction.

Photosynthesis is the fixation of atmospheric carbon dioxide into organic compounds; use of water as the electron donor by photoautotrophs during photophosphorylation results in the production of oxygen. Light reaction of photosynthesis includes trapping of Sunlight by chlorophyll a and other accessory pigments and production of ATP and NADPH. Aerobic respiration is the breakdown of sugar/other food substances in the presence of oxygen to released energy. It includes glycolysis, Krebs cycle and electron transport chain. Glycolysis and Kreb cycle produce reducing compounds NADH, FADH$$_2$$ which are then oxidized in the presence of oxygen by the process of chemiosmosis to produce a large amount of ATPs. Anaerobic respiration/Fermentation is incomplete oxidation of food substances into alcohol and lactic acid with small amount of energy being released. This makes option E correct answer. 

Photosynthetic algae carry out fixation of carbon dioxide into glucose wherein the first step includes carboxylation of RuBP into unstable 6C compounds which are immediately broken down into 2 molecules of 3C compounds called as phosphoglyceraldehyde (PGA). The follow-up reactions of Calvin cycle leads to the formation of one glucose molecule by three successive cycles. After five seconds, the radioactive carbon will be present in PGA only as the formation of glucose takes 3 successive Calvin cycles. Acetyl CoA is produced during cellular respiration of glucose, photosynthetic carbon is not incorporated into ATP and ADP. So, the correct answer is B.  

• There are photosynthetic pigments in the chloroplast of the plant cells. These pigments absorb the light of a certain wavelength and utilize this light for performing photosynthesis. 
• The spectrum of the absorption can be recorded by studying the reactions and the pigments involved. 
• The curve representing the light absorbed at each wavelength by the pigment is called the absorption spectrum.
• The curve showing rate of photosynthesis at different wavelengths of light is called the action spectrum.
• Quantum yield in photosynthesis is the moles of CO$$_2$$ fixed per mole of quanta (photons) absorbed.
  
• The number of photons or quanta required by a plant or leaf to release one molecule of oxygen during photosynthesis is called quantum requirement.
  
• So, the correct answer is option B.

CAM or Crassulacean Acid Metabolism is a photosynthetic process found in plants living in arid habitats. The carbon fixation pathway in CAM photosynthetic process is an evolved one adapted to meet the arid conditions wherein the stomata in the leaves remain closed during the day so as to reduce evapotranspiration, but are open at night to collect carbon dioxide.

Peter Mitchell proposed that an electrochemical concentration gradient of protons across a membrane could be utilized to make ATP. He linked this process to osmosis, the diffusion of water across a membrane, this is the reason it is called chemiosmosis. More specifically, it relates to the generation of ATP by the movement of hydrogen ions across a membrane during cellular respiration. Hydrogen ions (protons) will diffuse from an area of high proton concentration to an area of lower proton concentration.

ATPase complex (also known as Coupling factor):

Thylakoids are membrane bound compartments inside chloroplast and cyanobacteria. 

Autotrophs are the organism that can manufacture their own food using materials from inorganic sources. These are also known as the producers and they are divided into two categories; the photoautotrophs and chemoautotrophs. Few examples are plants, green algae that includes the cyanobacteria and all the archaebacteria.