Enzymes

In aerobic respiration, oxygen is primarily used during the Electron Transport System (ETS). The ETS is the final stage of cellular respiration, occurring in the inner mitochondrial membrane, where oxygen is the final electron acceptor, forming water. Oxygen is not directly used in earlier stages of cellular respiration like glycolysis and the Krebs cycle. Here’s a breakdown of the options:
- Glycolysis: This process does not require oxygen and occurs in the cytoplasm, producing pyruvate without any oxygen consumption.
- Glycolysis and Krebs cycle: Although the Krebs cycle requires oxygen indirectly (since it regenerates NAD and FAD in an oxygen-dependent manner), oxygen itself is not directly consumed until the ETS.
- Krebs cycle and ETS: The Krebs cycle itself does not use oxygen directly, but oxygen is required in the ETS to accept electrons and produce water.
- ETS (Electron Transport System): This is where oxygen is directly used in the process of accepting electrons to form water. Thus, the correct answer is ETS (Electron Transport System), where oxygen is directly utilised.

From the table provided: \begin{itemize} \item The combination for III is Glutamic acid + NH + ATP forming Glutamine + ADP + iP (Enzyme class 6). \item The combination for IV is Malate + NAD forming Oxaloacetate + NADH + H (Enzyme class 1). \end{itemize} These match the correct enzyme classes, confirming that the correct answer is III and IV.

- Assertion (A) is true: Arachis (peanut) is indeed a geocarpic plant, meaning that its fruit develops underground.
- Reason (R) is also true: Arachis seeds are non-endospermic, meaning they do not have a nutritive endosperm for embryo development, unlike many other seeds.
- However, while both the assertion and reason are true, the reason does not provide a direct explanation for the assertion. The geocarpic nature of Arachis is due to its fruit development underground, not because the seeds are non-endospermic. Therefore, (R) is not the correct explanation of (A).

This reaction involves the conversion of Phosphoglyceric acid to Bisphosphoglyceric acid. This step is part of the glycolysis pathway, and the enzyme involved is Phosphoglycerokinase. It catalyzes the transfer of a phosphate group from ATP to 3-phosphoglycerate, forming 1,3-bisphosphoglycerate. The correct enzyme for this reaction is Phosphoglycerokinase.

In the given diagram of ATP synthesis, the process occurs in the oxysome of mitochondria. ATP is synthesized via a proton gradient that is built across the mitochondrial membrane. The correct identification of components involved is:
Step 1: The protons ( ) are pumped across the membrane, resulting in a proton gradient.
Step 2: and refer to the F0F1-ATPase, which is responsible for ATP synthesis in the mitochondria. F0 acts as the proton channel, while F1 is the ATP synthesis site.
Step 3: The indicates the number of protons required for the synthesis of one molecule of ATP, moving through the F0 channel and driving the ATP synthesis at F1.
Thus, the correct answer is (1) .