**Q10: Which one of the following organs/tissues has a strict glucose requirement for their energy metabolism?***Explanation*: This question tests the understanding of glucose metabolism and its importance for specific organs or tissues in the body. **Ethanol Metabolism Pathways in the Liver****Cytosol:****A. Pathway 1:** Major pathway of ethanol metabolism in the liver.- **Reaction:** - Ethanol (CH₃-CH₂-OH) is converted to Acetaldehyde (CH₃-C=O-H) through the enzyme ADH (Alcohol Dehydrogenase). - During this process, NAD⁺ is reduced to NADH + H⁺.**B. Pathway 2:** Microsomal Ethanol Oxidizing System (MEOS).- **Reaction:** - Ethanol (CH₃-CH₂-OH) is converted to Acetaldehyde with the involvement of the enzyme CYP2E1. - NADPH + H⁺ + O₂ are converted to NADP⁺ + 2H₂O in this pathway.**Mitochondrion:**- Acetaldehyde is further oxidized to Acetate (CH₃-C=O-OH) by the enzyme ALDH (Aldehyde Dehydrogenase).- During this process, NAD⁺ is again reduced to NADH + H⁺, and Acetate is converted to Acetate and Water (H₂O).**Note:** Excess alcohol consumption increases the NADH:NAD⁺ ratio in the cytosol of hepatocytes.

Metabolism is a complex process and involves the conversion of calories into energy that is utilised by the body to function. Various metabolic organs such as brain, heart, liver, adipose tissue and pancreas are involved in the control of energy metabolism. LIver is the main blood glucose regulating organ in the . It plays a role in controlling the various glucose pathways such as glycogenesis, glycogenolysis, glycolysis and gluconeogenesis Glucose is the primary source of energy for every cell in the body. Brain, being rich in neurons utilises the maximum amount of glucose for its energy metabolism. Major amount of energy is consumed at the synapses. Hence the correct answer is BRAIN.