NST 103 Midterm 3 2025/2026 – 300+ Verified Q&As on Lipogenesis, Ketone Bodies, Amino Acid Catabolism, Urea Cycle, Cholesterol Synthesis, and the Pentose Phosphate Pathway

This NST 103 Midterm 3 (2025/2026 Edition) document features over 300 expertly solved questions and answers covering advanced metabolic topics crucial to understanding human energy balance and biochemical adaptation. Designed for students in Nutritional Sciences, Biochemistry, Metabolic Biology, or Pre-Medical programs, this resource reflects the depth and breadth expected on upper-division university midterm exams. The document covers complex pathways and regulatory mechanisms including: Amino acid degradation, including glucogenic vs. ketogenic intermediates and TCA cycle integration Fatty acid synthesis (lipogenesis): enzymes (ACC, FAS, ACL), substrates (acetyl-CoA, malonyl-CoA, NADPH), and pathway regulation by insulin, glucagon, and AMPK Palmitate synthesis and elongation, including desaturase enzymes and essential fatty acid families (ω-3 and ω-6) Ketone body production during fasting/starvation: HMG-CoA pathway, mitochondrial β-oxidation, and ketone transport to peripheral tissues Cholesterol synthesis from acetyl-CoA via HMG-CoA reductase, with regulation by statins, feedback inhibition, and SREBP Pentose Phosphate Pathway (PPP): oxidative and non-oxidative branches, NADPH and ribose-5-phosphate generation, enzyme deficiencies (e.g., G6PDH) TAG synthesis and glycerol metabolism in liver and adipose tissue Clinical implications including: Ketoacidosis and insulin deficiency Hemolytic anemia due to G6PDH deficiency Effects of dietary CHO on lipogenesis Metabolic response to starvation and low-carb states This material is especially useful for: Students enrolled in NST 103 or related metabolic physiology courses Undergraduate and graduate learners in Nutrition, Biochemistry, or Medical Sciences Anyone preparing for MCQ-heavy midterm exams on metabolism, regulation, and energy homeostasis Learners needing clear explanations of high-yield topics such as acetyl-CoA transport, TAG formation, and cholesterol homeostasis The guide is structured logically by topic, with biochemical pathways, enzymes, substrates, and regulation all addressed with clinical context where applicable—perfect for mastering midterm material with precision. Keywords: NST 103 midterm, amino acid catabolism, ketogenic intermediates, glucogenic pathways, fatty acid synthesis, palmitate, ketone bodies, β-oxidation, cholesterol synthesis, HMG-CoA reductase, pentose phosphate pathway, NADPH, ribose-5-phosphate, G6PDH deficiency, urea cycle, insulin regulation, metabolic adaptation, fasting vs fed state, TAG synthesis