1st Semester 2024-2025 Biochemistry Lecture - Fatty Acid and Triglycerides Metabolism PDF

BIOCHEMISTRY LECTURE 1ST SEMESTER 2024-2025 Dr. Amado A. Viesta Jr ACTIVITY – WEEK 11 – FATTY ACID AND TRIGLYCERIDES METABOLISM Name: Arthur Grisha C. Rivera Section: 1- E Question 1: How many NADPH + H will the cells need to be able to synthesize a 16-carbon saturated fatty acid, EXPLAIN. To sy...

BIOCHEMISTRY LECTURE 1ST SEMESTER 2024-2025 Dr. Amado A. Viesta Jr ACTIVITY – WEEK 11 – FATTY ACID AND TRIGLYCERIDES METABOLISM Name: Arthur Grisha C. Rivera Section: 1- E Question 1: How many NADPH + H will the cells need to be able to synthesize a 16-carbon saturated fatty acid, EXPLAIN. To synthesize a 16-carbon saturated fatty acid, cells require 8 NADPH + H molecules. This process involves two primary steps: chain initiation and chain elongation. During chain initiation, acetyl-CoA combines with malonyl-CoA to form a 4-carbon intermediate. This reaction necessitates 1 NADPH + H for the reduction of the keto group to a hydroxyl group. In the subsequent chain elongation phase, the 4-carbon intermediate undergoes multiple cycles of adding two carbons to the chain. Each elongation cycle requires 1 NADPH + H for two reduction steps. As a 16-carbon fatty acid requires 7 elongation cycles, a total of 7 NADPH + H are needed for this step. Consequently, the overall NADPH + H requirement for synthesizing a 16-carbon saturated fatty acid is 1 for initiation and 7 for elongation, resulting in a total of 8 NADPH + H molecules. Question 2: If the cells synthesize a 16-carbon fatty acid, how many spirals or cycles will the cells need to form palmitic acid (the most common fatty acid synthesized by the cell), EXPAND AND EXPLAIN? Fatty acid synthesis is a cyclical process that involves the sequential addition of two-carbon units to a growing fatty acid chain. To produce palmitic acid, a 16-carbon fatty acid, cells need to complete 8 cycles of this process. Each cycle adds a two-carbon unit, starting from the initial two-carbon unit (acetyl-CoA) and ending with the desired 16-carbon chain. Question 3. AcylCoA dehydrogenase plays a key role in the electron transport chain by transferring electrons to electron-transferring flavoproteins (ETFs). Explain how it works biochemically. Acyl-CoA dehydrogenase is a key enzyme in the beta-oxidation pathway, which breaks down fatty acids. It removes hydrogen atoms from the fatty acid molecule and transfers them to a FAD cofactor. The reduced FAD then donates its electrons to electron-transferring flavoproteins (ETFs), which in turn pass these electrons to the electron transport chain. This process ultimately contributes to the generation of ATP, the cell's energy currency. Question 4. What is carnitine, its function, and What happens in carnitine deficiency Carnitine is a vital molecule that helps transport fatty acids into mitochondria for energy production. When carnitine levels are low, the body struggles to use fatty acids as fuel, leading to symptoms like muscle weakness, fatigue, and hypoglycemia. Carnitine deficiency can be caused by genetic factors, dietary issues, or underlying medical conditions. Treatment often involves supplementing with carnitine or addressing the underlying cause. Question 5. How ketone bodies are formed in the liver? and Why ketone bodies are not degraded in the liver. Ketone bodies are produced by the liver when glucose levels are low. They are formed from fatty acids and serve as an alternative fuel source for tissues like the brain and heart. There is fatty acid breakdown, Acetyl - CoA Accumulation, Ketogenesis. The liver prioritizes exporting ketone bodies rather than using them for its own energy needs, ensuring that other tissues have access to this essential fuel during times of metabolic stress. Or in other terms, enzyme regulation, metabolic needs, and mitochondrial compartmentalization. Question 6 State the role of hormones in lipogenesis and its function. Lipogenesis, the process of making fat, is controlled by hormones. Insulin encourages fat storage, while glucagon, cortisol, and growth hormone can influence fat production under certain conditions like chronic stress, excessive intake of carbohydrate, low blood glucose levels. For example, glucagon can have an opposite effect to insulin. Prevent lipogenesis and promote lipolysis, the breakdown of stored triglycerides. This helps the body store excess energy and maintain cell structure.