These MP Board Class 11th Biology Notes for Chapter 13 Photosynthesis in Higher Plants help students to get a brief overview of all the concepts.
MP Board Class 11th Biology Notes Chapter 13 Photosynthesis in Higher Plants
→ Photosynthesis is a basic most significant process on which the life on earth entirely depends.
→ It is the formation of carbon containing compounds from CO2 and H2O by illuminated green cells.
→ There are two phases in the process of photosynthesis, photochemical (light dependent) and chemical (light independent).
→ Two kinds of photosystems control the entire light phase. The pigment system-I (PS-I) and pigment system-II (PS-II).
→ Two kinds of photophosphorylation are there : cyclic and non-cyclic.
→ The dark or chemical phase is called Calvin cycle. This cycle includes carboxylative phase, reductive phase and regenerative phase. Many enzymes control the process.
→ The first CO2 acceptor is ribulose diphosphate and the first stable product is phosphoglycer- aldehyde.
→ Hatch and Slack cycle also called C4 cycle is reported in many grasses and some dicots. The CO2 acceptor is phosphoenol pyruvate (PEP) and the first stable product is oxaloacetate.
→ Blackman and his associates (1905-1915) discovered the light and dark reactions of the pho-tosynthesis.
→ The law of minimum was proposed by Liebig.
→ Law of limiting factors was proposed by Blackman in 1905.
→ Melvin, Calvin and Andrews Benson (1940-1950) have described the C3 cycle of photosyn-thesis.
→ Daniel Arnon has shown that the light reaction of photosynthesis takes place in grana, whereas dark reaction takes place within stroma.
→ Rouhani and his associates (1973) have discovered the CAM cycle of photosynthesis in Sedum (a succulent plant).
→ Robert Emerson discovered the red drop and Emerson enhancement effect. Two pigment system was also discovered by them.
→ Chl-a 700 (P 700) was discovered by Clayton which is the reaction centre of PS-I.
→ Photochemical breakdown of water always takes place during PS-II only because of the presence of a strong oxidant NADP.
→ The end-products of light reaction are ATP, O2 and NADPH2.
→ The acceptor of CO2 molecule in C3 cycle is Ribulose-1, 6-Diphosphate.
→ RuDP carboxylase enzyme catalyze the carboxylation reaction of C3 cycle and is active only in presence of higher CO2 concentration.
→ The first stable product of C3 cycle is PGA.
→ The CO2 acceptor molecule of C4 cycle is PEP.
→ PEP carboxylase enzyme catalyzes the carboxylation reaction in C4 plants and is active in presence of lower CO2 concentration too.
→ The leaves of C4 plants exhibit Kranz type of leaf anatomy.
→ In C4 plants PEP-C enzyme is found within the chloroplast of mesophyll cells, whereas RuDP-C enzyme is found within the chloroplast of bundle sheath cells.
→ In C4 plants carbohydrates are synthesized within bundle sheath cells.
→ The amount of chlorophyll in plants is measured with the help of colorimeter.
→ H2O is the hydrogen donor of green plants, whereas H2S functioning as hydrogen donor in bacterial photosynthesis.
→ The number of oxygen atoms evolved from per quantum of light is called as quantum yield.
→ Red light shows highest rate of photosynthesis and blue light shows second highest rate of photosynthesis.