Q: How many ATP and NADPH + H+ are required for the synthesis of 1 molecule of glucose in c3 and c4 plants respectively ?

In C\$_3\$ pathway in Calvin cycle, one CO\$_2\$ molecule require 3ATP and 2 NADPH and as the cycle turn to be six times for the formation of one glucose molecule 18 ATP and 12 NADPH are required while in C\$_4\$ plant one CO\$_2\$ molecule needs 5 ATP molecule as the process occurs in mesophyll cells to bundle sheath cells and came back to mesophyll cells again requires more energy so in six turns of cycle 30 ATP and 12 NADPH are required.So the correct option is 18 ATP, 12 NADPH, and 30 ATP and 12 NADPH".

Question 1

Write the balanced chemical equation for the process of photosynthesis.

Accepted Answer

A straightforward word condition that can be utilized to depict the procedure of photosynthesis isCarbon dioxide + water &#8212; > Glucose + Oxygen + water. A fair synthetic condition for the procedure can be composed as 6$CO_2$ + 6$H_2O$ &#8212; > $C_6H_{12}O_6$ + $6O_2$. Generally, photosynthesis utilizes light to convert Carbon dioxide into Glucose.

Question 2

Explain chemiosmotic hypothesis for ATP synthesis.

Accepted Answer

The chemiosmotic hypothesis was proposed by Peter Mitchell. The ATP and NADH$_2$ generated during the light reaction is used for carbon dioxide fixation during the dark reaction.According to the chemiosmotic hypothesis, ATP is produced by due to the proton gradient created across the mitochondrial membrane. The essential components required for chemiosmosis are proton pump, proton gradient and ATP synthase. ATP synthase is an enzyme which helps in ATP synthesis. The enzyme ATP synthase has two part $F_0$ and $F_1$. $F_0$ is the part which transports protons across the membrane as a transmembrane channel while configuration changes in $F_1$ activates the enzyme. They phosphorylate ADP i.e., add one more phosphorus group to the ADP and converts ADP(adenosine diphosphate) to ATP (adenosine triphosphate). The proton gradient developed across the membrane is the driving force of ATP synthase.

Question 3

Explain the mechanism of photosynthesis.

Accepted Answer

Photosynthesis is the process by which green plants prepare their food in the presence of sunlight. Green plants utilize carbon dioxide and water to make carbohydrate. The reaction of photosynthesis can be depicted in the  following equation:$6CO_2+12H_2O\xrightarrow{chlorophyll+sunlight}C_6H_12O_6+6O_2+6H_2O$The process of Photosynthesis is composed of following step:(a) Absorption of light energy by chlorophyll.(b) Conversion of light energy into chemical energy(c) splitting of water molecules into hydrogen and oxygen.(d) Reduction of carbon dioxide to form carbohydrate These steps need not take place one after another immediately. For example; desert plants take up carbon dioxide at night to make an intermediate. During daytime. they make carbohydrate. After photosynthesis, carbohydrate is converted into starch and starch is stored in different plant organs.

Question 4

How many ATP and NADPH + H+  are required for the synthesis of 1 molecule of glucose in c3 and c4 plants respectively ?

Accepted Answer

In C$_3$ pathway in Calvin cycle, one CO$_2$ molecule require 3ATP and 2 NADPH and as the cycle turn to be six times for the formation of one glucose molecule 18 ATP and 12 NADPH are required while in C$_4$ plant one CO$_2$ molecule needs 5 ATP molecule as the process occurs in mesophyll cells to bundle sheath cells and came back to mesophyll cells again requires more energy so in six turns of cycle 30 ATP and 12 NADPH are required.So the correct option is 18 ATP, 12 NADPH, and 30 ATP and 12 NADPH&#34;.

Question 5

Give comparison between the following : (a) $C_3$ and $C_4$ pathways, (b) Cyclic and noncyclic photophosphorylation.(c) Anatomy of leaf in $C_3$ and $C_4$ plants.

Accepted Answer

(a)C&#8323; pathwayC&#8324; pathway1. Known as Calvin Cycle ( due to Malvin Calvin.)Known as Hatch and Slack (due to Marshall Davidson Hatch and C.R. Slack.)2. This cycle is present in all the plants. This cycle is present only in C&#8324; plants.3. The first stable product is a 3 Carbon (3C) compound, called Phosphoglyceric acid (PGA).The first stable product is a 4 Carbon (4C) compound, called Oxaloacetic acid (OOA).4. The carbon dioxide fixation takes place at only one place.The carbon dioxide fixation takes place twice (first in mesophyll cells; second in bundle-sheath cells).5. These plants can only perform photosynthesis when the stomata is open.These plants can perform photosynthesis even if the stomata is closed.6. Their leaves do not have Kranz Anatomy.Their leaves do have Kranz Anatomy.7. Example: Cotton, sunflower, rye, oats, et cetera.Example: Sugarcane, maize, amaranthus, et cetera.(b) &#10; &#10;  &#10;  Cyclic photophosphorylation.&#10;  &#10;  &#10;  Noncyclic photophosphorylation.&#10;  &#10; &#10; &#10;  &#10;  1. Predominant in bacteria.&#10;  &#10;  &#10;  Predominant in green plants.&#10;  &#10; &#10; &#10;  &#10;  2. Only photosystem I (PS I) is involved. &#10;  &#10;  &#10;  Both photosystem I and II (PS I and II) are involved.&#10;  &#10; &#10; &#10;  &#10;  3. Since PS I is involved, the active reaction center is P&#8327;&#8320;&#8320;.&#10;  &#10;  &#10;   The active reaction center is P&#8326;&#8328;&#8320;.&#10;  &#10; &#10; &#10;  &#10;  4. The movement of electrons is cyclic.&#10;  &#10;  &#10;  The movement of electrons is non-cyclic.&#10;  &#10; &#10; &#10;  &#10;  5. This process produces no NADPH and no O&#8322;, but it does make ATP. &#10;  &#10;  &#10;   This process produces both NADPH and ATP, and O&#8322; is evolved as a by-product.&#10;  &#10; &#10; &#10;  &#10;  6. Photolysis (water-splitting) is absent.&#10;  &#10;  &#10;  Photolysis (water-splitting) is present.&#10;  &#10; &#10; &#10;  &#10;  7. The electrons travel back to PS I and completes the cycle.&#10;  &#10;  &#10;  The electrons from PS I accepted by NADPH, making the cycle incomplete.&#10;  &#10; &#10;(c) Leaf anatomy in 1. C&#8323; plants: Leaves of C&#8323; plants display only one type of cell, called mesophyll cells. It contains mesophyll chloroplast due to which, C&#8323; pathway occur. These plants show normal leaf anatomy.2. C&#8324; plants: Leaves of C&#8324; plants display two type of cells: [outer] mesophyll cells and [inner] spongy bundle-sheath cells. So, the leaves of C&#8324; plants contain two types of chloroplast: mesophyll chloroplast and bundle sheath chloroplast i.e., dimorphic chloroplast. Thus, C&#8324; pathway occurs. This anatomy of leaves in C&#8324; plants is called Kranz Anatomy.

Question 6

Write any six differences between cyclic photophosphorylation and non-cyclic photophosphorylation.

Accepted Answer

Cyclic photophosphorylationNon-cyclic photophosphorylation  1- It occurs in photosystem I. 1- It occurs in both photosystem I and photosystem II. 2- Only Atp is produced 2- Both ATP and NADPH are produced. 3- Electrons expelled by photosystem and return back. 3- Electrons expelled by photosystem but do not return back. 4- Photolysis of water does not occur. 4- Photolysis of water occur. 5- Oxygen is not released. 5- Oxygen is released. 6- Water is not consumed. 6- Water is consumed.

Question 7

How many turns of Calvin cycle are required for formation of one molecule of glucose?

Accepted Answer

Carbon dioxide fixation occurs during Calvin cycle. There are three stages in the process of Clavin cycle as carboxylation, reduction, and regeneration. One turn of Calvin cycle fixes one molecule of carbon dioxide. There are 6 atoms of carbon required for the synthesis of one glucose molecule. Hence, to produce one molecule of hexose sugar, six turns of Calvin cycle are required. Thus, the correct answer is option C.

Question 8

Which of the following is not required for chemiosmotic process?

Accepted Answer

A. Proton gradient is required because the breakdown of this gradient leads to release of energy.B. Splitting of water is required which takes place on the inner side of the membrane and the protons that are produced, they accumulate within the lumen of the thyllakoids.C. ATP synthase enzyme is required that allows diffusion of protons back across the membrane, this releases energy to activate ATPase enzyme which catalyses the formation of ATP.D. Closed membrane system is not required. Only a membrane is required for the development of a proton gradient across the membrane of the thyllakoid and the proton accumulation is towards the inside of the membrane.So, the correct answer is 'Closed membrane system'.

Question 9

Give a graphic outline of the biosynthetic phase of photosynthesis.

Accepted Answer

In the biosynthetic phase of photosynthesis, ATP and NADPH are used for synthesizing the food. CO2 is fixed to form CO2 fixation product. This stage is also called the dark phase as it is independent of light but deals with the products of the light reaction.  It takes place in the stroma of the chlorophyll.  During this phase, glucose is formed by using ATP and NADPH.

Question 10

Distinguish between photosynthesis and respiration.

Accepted Answer

PhotosynthesisRespirationIt takes place only in the presence of sunlight.It continues throughout day and night, in sun and darkness.It occurs only in the green cells of the plant.It occurs in all the cells of an organism.It is an endothermic reaction as it absorbs sunlight.It is an exothermic reaction, as it gives out energy.It utilises carbon dioxide and water.It evolves carbon dioxide and water.It builds up complex compounds such as carbohydrates from simple inorganic compounds. So, it is an anabolic process.It breaks complex substances into simple substances. So, it is a catbolic process.It converts light energy into chemical energy.It releases potential or chemical energy which is used variously in the body.Carbon dioxide and water are raw materials for photosynthesis.Sugars and oxygen are raw materials for respiration.It produces ATP by harvesting light energy.It forms ATP from energy liberated during oxidation of food.Hydrogen of water is used in the synthesis of NADPH.Hydrogen of food is used in the formation of NADP, NADPH and $FADH_{2}$.ATP and NADPH are used in the synthesis of organic compounds.ATP and reduced coenzymes are made available to cells for various metabolic activities.