Importance of day length in flowering of plants was first shown in
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Solution
Photoperiodism was first studied by Garner and Allard(1920). They observed that “Maryland Mammoth”variety of tobacco could be made to flower in summer by reducing the light hours with artificial darkening. It could be made to remain vegetative in winter by providing extra light.
In leaves of C4 plants malic acid synthesis during CO2 fixation occurs in
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Solution
In leaves of C4 plants, malic acid synthesis during CO2 fixation occurs in mesophyll cells. The mesophyll cells perform C4 cycle and the cells of bundle sheath perform C3 cycle.
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma.This damage will have the most direct effect on which of the following processes?
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Solution
Damage in thylakoids have direct effect on the synthesis of ATP.
The wavelength of light absorbed by Pr form of phytochrome is
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Solution
The Pr form absorbs light between 660 to 680 nm and absorbs at a peak of 666 nm. It is the form synthesized in dark-grown seedlings. When Pr absorbs red light, it is converted to the Pfr form.
In the leaves of C4 plants, malic acid formation during CO2 fixation occurs in the cells of
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Solution
In C4 plants, C4 cycle occurs in mesophyll cells and C3 -cycle occurs in a bundle sheath.
During photorespiration, the oxygen consuming reaction(s)occur in
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Solution
Photorespiration is the process which occurs in C3 plants.In this process, peroxisomes, chloroplast and mitochondria take part. The oxygen consuming reactions occurs in peroxisomes and stroma of chloroplast while CO2 releasing reaction occurs in mitochondria.
At low light intensities, the relation between the incident light and CO2 fixation rates is
In photosystem-I the first electron acceptoris
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Solution
In Photosystem I or Photoact I electrons released by P-700 are accepted by a substance of iron-sulphur-protein complex denoted as A(FeS). A(FeS) is thus reduced and it passes these high electrons to oxidised ferredox in and it gets reduced. From reduced Fd these electrons are passed to FAD which now reduced to FADH2 and then electrons and hydrogen are accepted by NADP which makes NADPH2 . Here photosystem I ends.
Chlorophyll in chloroplasts is located in:
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Solution
Internally a chloroplast contains a matrix or stroma which is similar to cytoplasm in its constitution. It contains DNA, RNA, ribsomes, enzymes for CO2 assimilation,proteins, starch grains and fat droplets or plastoglobuli.In the matrix or stroma embedded a number of flattened membranous sacs called thylakoids or lamellae. At places the thylakoids are aggregated to form stacks called grana.
As compared to a C3– plant, how many additional molecules of ATP are needed for net production of one molecule of hexose sugar by C4 – plants:
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Solution
Equation for C4 pathway
6 PEP +6 RuBP + 6CO2 + 30 ATP +12 NADPH +6PEP + 6 RuBP+ C6H12O6+ 30 ADP + 30 H3PO4 + 12NADP +The net reaction of C4 dark fixation is
6RuBP +6CO2 + 18ATP + 12 NADPH + 6 RuBP +C6H12O6+ 18 ADP + 18 P + 12 NADP+