In photorespiration, glycolate is converted into serine and carbon dioxide in:
In the C4 pathway, which of the following molecules combines with carbon dioxide?
(1) glyceraldehyde phosphate
(2) ribulose biphosphate
(3) phosphoenol pyruvic acid
(4) citric acid
An action spectrum of photosynthesis was first described by:
(1) Jan Ingenhousz
(2) Julius von Sachs
(3) T.W. Engelmann
(4) Cornelius van Niel
(3) Read page 208, XI NCERT
Dark reactions of photosynthesis are actually not totally independent of light as:
(1) The initial reactions occur in the presence of light.
(2) The reaction will be inhibited by the presence of light.
(3) They can occur during the day as well.
(4) They utilize the products of the light reaction.
(4) Read page 209, XI NCERT
All the following regarding the role of xanthophylls and carotenoids in photosynthesis are correct except:
(1) They act as accessory pigments
(2) Their peak absorption is in blue and red regions of VIBGYOR
(3) They enable a wider range of wavelength of incoming light to be utilized for photosynthesis
(4) They protect chlorophyll a form of photo-oxidation.
(2) Read page 211, XI NCERT
The chloroplast stroma lamella membrane:
(1) Lack PS II as well as NADP reductase enzyme.
(2) Lack PS II but have NADP reductase enzyme.
(3) Lack NADP reductase enzyme but have PS II.
(4) Have PS II as well as NADP reductase enzyme.
(1) Read page 213, XI NCERT
Which stage of the Clavin Cycle utilizes ATP?
(4) Both 2 and 3
(3) Read page 217, XI NCERT
Which of the following are special features of the C4 plants?
I. They have a special type of leaf anatomy.
II. They tolerate higher temperatures and show a response to high light intensities.
III. They lack photorespiration and have greater productivity of biomass.
(1) Only I and II
(2) Only I and III
(3) Only II and III
(4) I, II and III
(4) Read page 2018, XI NCERT
Compared to retinal, chlorophyll can be described as a pigment that has a
(1) narrow absorption range but high efficiency
(2) narrow apsorption range but low efficiency
(3) wide absorption range but high effeciency
(4) wide absorption range but low efficiency
(1) This is the reason for the use of chlorophyll in photosynthesis. The range PAR not covered by chlorophyll are covered by carotenoids.
Consider the situation where photosynthesis is going on at a steady pace in a typical experiment with a light on, and carbon dioxide is being combined with ribulose-bisphosphate (RuBP) to produce 3-phosphoglycerate (3PG). Then suddenly the source of carbon dioxide is eliminated. What changes in the concentrations of 3PG and RuBP would occur?
(1) 3PG levels rise, RuBP levels fall.
(2) 3PG levels fall, RuBP levels rise.
(3) 3PG levels rise, RuBP levels rise.
(4) 3PG levels fall, RuBP levels fall.
(2) Elimination of a source of CO2 would block the action of RUBISCO, which required CO2 as a subtrate. There would be no further production of 3-phosphoglycerate (3PG).
The remaining reactions of the Clavin Cycle are not block by the absence of CO2. Intermediates in the cyclic pathway would be converted to ribulose-1,5-bisphosphate (RuBP) and the level of RuBP would rise.