IGNOU BBYCT-137 December 2024 Previous Year Question Paper

Q1.(a) Fillin the blanks : 1x3=3 @)_ Salt-sensitive plants are called Gi) The plant growth regulator, delays the senescence of green leaves. Gii) At full turgor, wy, of a cell will

(b) Choose the correct option from the given choices : pxde2

(i) Leaves of Potamogeton-type are (epistomatic/ astomatic).

(ii) (Cobalt/Zinc) is a component of Vitamin Bie.

(ii) Cytochromes involved in bacterial photosynthesis is of (४ / ‘b’) type.

(iv) (TCA / Calvin) cycle is considered as amphibolic.

(c) Define the following terms : 1x5=5 @) Salinity

(1) Bioassay

(ii) Anaerobiosis

(iv) Cavitation

(v) Absorption spectrum

Q2.Describe the principal events of Calvin- Benson’s cycle of photosynthetic carbon reduction.

Q3.Describe the Crassulacean Acid Metabolism and its significance to plants. 7+3=

(10)

Q4.Provide a comparative account of three important pathways for the movement of water from epidermis to the endodermis in a primary root of a terrestrial plant. Substantiate your answer with a labelled sketch.

Q5.(a) With the help of a schematic diagram, describe the ultrastructure and organization of mitochondrion. 5

(b) Discuss pentose-phosphate pathway with the help of a flowchart.

Q6.(a) Describe the events of ‘nodule’ formation during biological No-fixation. 5

(b) Discuss the structure and functional role of nitrogenase in N»-fixation.

Q7.Describe the Transpiration Pull and Cohesion Tension Theory to explain the ascent of sap in tall trees.

Q8.Write short notes on any two of the following : 5x2=10

(a) Plant response to osmotic stress

(b) Gibberellins

(c) Mycorrhiza

(d) Miinch-flow hypothesis [

(71)