Respiration In Plants

Answer (a) 2

Answer (c) Dephosphorylation

There is no transfer o f electron from cyt b to cyt c as they are not nearby

Anaerobic respiration generates only 2 ATP per glucose molecule. So, on the breakdown of 20 glucose molecules, 40 ATP will be produced.

Fructose-1, 6-diphosphate (6C) splits up to form one molecule of each of 3C compound, i.e., glyceraldehyde3-phosphate or 3-phosphoglyceraldehyde (PGAL) and dihydroxy acetone-3-phosphate (DHAP) by cleavage.

In Krebs? cycle two decarboxylations occur at following steps:

Answer (d) Respiration

In anaerobic respiration there is no consumption of oxygen and carbon dioxide is produced in most of the cases,
e.g.,
As CO_2 2CO_2
infinity
Therefore, the respiratory quotient is infinity

Solution: Number of Carbon Atoms in n Moles of Citric Acid

Citric acid is a naturally occurring organic acid with the molecular formula C₆H₈O₇, meaning that each molecule of citric acid contains 6 carbon atoms.

Step 1: Understanding the Chemical Formula

The molecular formula of citric acid is C₆H₈O₇, which indicates that each molecule contains:

• 6 carbon atoms (C)
• 8 hydrogen atoms (H)
• 7 oxygen atoms (O)

Step 2: Finding the Number of Carbon Atoms in n Moles

One mole of citric acid contains 6 carbon atoms per molecule. Therefore, in one mole of citric acid, the number of carbon atoms is:

6 × (1 mole) × (6.022 × 10²³ molecules/mole) = 6 × 6.022 × 10²³ carbon atoms

If we have n moles of citric acid, the number of carbon atoms will be:

6 × n × 6.022 × 10²³ = 6n × 6.022 × 10²³ carbon atoms

So, the number of carbon atoms in n moles of citric acid will be 6n, as the correct answer from the given options.

Conclusion:

The number of carbon atoms in n moles of citric acid is 6n, corresponding to Option 2: 6n.

The Krebs cycle, also known as the citric acid cycle or TCA cycle, is a critical step in cellular respiration that takes place in the mitochondria. It plays an essential role in producing ATP, the primary energy source used by cells for various functions.
Role of NADH in ATP Production:
During the Krebs cycle, the main function is to oxidize acetyl-CoA, a derivative of glucose, fatty acids, or proteins. As the cycle progresses, energy from these substrates is captured in the form of high-energy molecules, namely NADH and FADH₂.
Steps Leading to NADH Formation:
1. Oxidation of Isocitrate: Isocitrate, formed from citrate, is oxidized by NAD⁺, reducing it to NADH while converting isocitrate into α-ketoglutarate. This step also releases CO₂.
2. Oxidation of α-Ketoglutarate: In the next step, α-ketoglutarate is further oxidized, producing another NADH molecule while forming succinyl-CoA. Another CO₂ is released.
3. Succinate Dehydrogenation: Although not directly part of the Krebs cycle, the electron carrier FADH₂ is generated in this part of the process, but NADH remains the major player.
At each of these points, NAD⁺ is reduced to NADH, capturing energy that will later be used for ATP production.
How NADH Contributes to ATP Production:
The NADH molecules formed during the Krebs cycle are crucial for the production of ATP. These NADH molecules do not directly generate ATP in the Krebs cycle itself. Instead, they transfer their high-energy electrons to the electron transport chain (ETC) located in the inner mitochondrial membrane. The ETC consists of a series of protein complexes that pass the electrons through their structures, releasing energy in small, controlled steps.
The Electron Transport Chain and Oxidative Phosphorylation:
Once NADH donates electrons to Complex I (NADH dehydrogenase) in the ETC, the energy released is used to pump protons (H⁺) across the inner mitochondrial membrane, creating a proton gradient. This proton gradient generates a proton-motive force (PMF), which powers the enzyme ATP synthase. ATP synthase allows protons to flow back into the mitochondrial matrix, and the energy released from this flow is used to convert ADP and inorganic phosphate (Pi) into ATP. This process is called oxidative phosphorylation and is where most ATP is produced.
Each NADH molecule can generate approximately 2.5 ATP molecules via this process, depending on the efficiency of the electron transport chain and ATP synthase. This makes NADH one of the most important molecules for ATP production in the cell.
Additional Notes:
While NADH is the primary electron donor in oxidative phosphorylation, FADH₂ also contributes to ATP production, but it donates electrons at a later stage in the electron transport chain, resulting in fewer ATP molecules generated per FADH₂ (around 1.5 ATP). Therefore, NADH is more efficient in ATP production compared to FADH₂.
Conclusion:
NADH is a critical source of ATP during cellular respiration. It captures energy from food molecules in the Krebs cycle and donates this energy to the electron transport chain, where it powers ATP production through oxidative phosphorylation. Without NADH, the cell would not be able to produce sufficient ATP for energy-demanding processes.

Inorganic phosphate ( ) plays a crucial role in the process of glycolysis, particularly during the following steps: Step: Conversion of glyceraldehyde-3-phosphate (G3P) to 1,3-bisphosphoglycerate: In this reaction, an inorganic phosphate ( ) is added to G3P, catalyzed by the enzyme glyceraldehyde-3-phosphate dehydrogenase. This step is essential for producing high-energy intermediates, which eventually lead to ATP generation. Although inorganic phosphate is involved in other stages like the Krebs cycle and ETS indirectly, its direct involvement in adding to metabolic intermediates is specific to glycolysis.