NCERT Class 11-Biology: Chapter – 13 Photosynthesis in Higher Plants Part 8 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 7:

What are the important events and end products of the light reaction?


Important light reaction events and final products are as follows. It is important to note that these events are not the order in which they happen but the order in which the scientists discover them.

Light absorption: The Light Harvesting Complex (LHC) performs light absorption.

Each photosystem has a light harvesting system of all pigments (except one chlorophyll-a molecule) . The antennas are also known as these pigments. These pigments absorb light from different wavelengths to improve the efficiency of the system. As a reaction centre, the single chlorophyll a molecule works.

Water division: sunlight energy is used to divide the water molecule into hydrogen ion and

NADP + to NADPH is used for the extra electron released after the split.

Oxygen release: after division of the water molecule oxygen discharges into the stomach.

High-energy intermediate formation (ATP and NADPH) : two energy-rich combinations ATP and NADPH are formed at the end of an electricity reaction.

Question 8:

In the diagram shown below label A, B, C. What type of phosphorylation is possible in this?

Chapter 13 - Question 8- The Diagram Shown below L …


When only PS I is functional, the electron is circulated within the photosystem and the phosphorylation occurs due to cyclic flow of electrons.

The type of phosphorylation process possible here is: cyclic photophosphorylation. Photophosphorylation is the synthesis of ATP from ADP and inorganic phosphate in the presence of light.

Question 9:

Why is the RuBisCo enzyme more appropriately called RUBP Carboxylase-Oxygenase and what important role does it play in photosynthesis?


Both carbon dioxide and oxygen have affinity with the enzyme of Rubisco. This is competitive, however. It is more closely related to than to oxygenation. It is the relative and concentration that affects Rubisco՚s binding to a particular molecule. Since it acts as both carboxylase and oxygenase, RUBP carboxylase – Oxygenase is better referred to.

Rubisco binds to in plants. In plants, Rubisco is binding with in a process known photorespiration to generate Phosphoglycerate and Phosphoglycerate. Photo vacuum reduces carbon attachment in plants

Rubisco catalyses the production of Oxaloacetic acid in plants due to the increase in carbon dioxide levels in the vascular bundle. In this case, photorespiration is avoided and carbon fixation is more efficient.

Question 10:

What special anatomical features are displayed by leaves of plants? How do they provide advantage over the structure of plants?


The leaf anatomy of the plants is special. The vascular bundles in leaves contain a sheath of large cells. Kranz Anatomy is called. In particular, chloroplast impregnates several layers of cells around the bundle cell. These cell thick walls cannot be exchanged for gasses. The sheath is without intercellular space.

Plants over plants are securely fastened with the bundle sheath. It helps to increase the level of carbon dioxide in the leaves. We know that it is competitive to bind Rubisco to and oxygen.

We also know that a certain molecule is affected by the relative concentration of carbon dioxide and oxygen. The high carbon dioxide concentration in these plants guarantees that the whole Rubisco binds to carbon dioxide and that no oxygen is binding.

Therefore, in these plants there is no photo vacuuming. This helps to prevent resource wastage and carbon fixation in these plants is highly efficient. These plants eventually produce more biomass than the plants.

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