NST 103 Midterm 3 2025/2026 – 200+ Solved Q&As on Lipid Transport, Lipoprotein Metabolism, Starvation Physiology, Gluconeogenesis, Amino Acid Catabolism & Urea Cycle

This expertly compiled NST 103 Midterm 3 (2025/2026) document delivers over 200 fully solved, high-yield questions and answers, providing a complete and focused review of lipid metabolism, energy regulation, gluconeogenesis, and amino acid degradation. Tailored for upper-division students in Nutritional Sciences, Biochemistry, Metabolic Biology, or Pre-Med programs, this review is structured to mirror midterm exam expectations and concept depth. Major topics covered include: Lipid transport mechanisms across lumen, enterocytes, lymph, blood, adipose, and tissues Lipoprotein metabolism: Chylomicrons, VLDL, IDL, LDL, HDL; exogenous and endogenous pathways Key apolipoproteins (Apo A-1, B-100, B-48, C-II, E) and their regulatory roles in lipid absorption and delivery Starvation and fasting adaptations: FFA and ketone body dynamics, TAG breakdown, insulin/glucagon effects, hormone-sensitive lipase regulation Gluconeogenesis (GNG): bypass steps, key enzymes (PEPCK, pyruvate carboxylase, fructose 1,6-bisphosphatase, glucose 6-phosphatase), hormonal control (insulin, glucagon), and substrate sources (lactate, glycerol, amino acids) Beta-oxidation of fatty acids: mitochondrial and peroxisomal processes, carnitine shuttle (CPT I, CPT II), ATP yields from palmitate Amino acid catabolism and nitrogen balance: transamination, deamination, mTOR regulation, ketogenic vs. glucogenic amino acids Urea cycle: enzymes, inputs, metabolic link to gluconeogenesis, and nitrogen disposal pathways Biotin, pyridoxine (vitamin B6) roles in transamination, carboxylation, and amino acid processing De novo lipogenesis (DNL): fatty acid synthesis from acetyl-CoA, malonyl-CoA, ACC regulation, desaturation, elongation, and essential fatty acids (omega-3 and omega-6 pathways) This document is highly recommended for: Students enrolled in NST 103, Human Metabolism, Advanced Nutrition, or Medical Biochemistry courses Learners preparing for in-depth MCQ exams and essay-based questions involving lipid and amino acid metabolism Candidates looking for a solid grasp on fasted state physiology, metabolic regulation, and coenzyme function Answers are accurate, clearly structured, and explained with attention to physiological context, biochemical regulation, and metabolic logic, making it a top-tier prep resource for academic success. Keywords: NST 103 midterm, lipid transport, chylomicrons, VLDL, LDL, HDL, apolipoproteins, fasting metabolism, hormone-sensitive lipase, gluconeogenesis, PEPCK, beta-oxidation, CPT1, ketone bodies, urea cycle, amino acid degradation, transamination, mTOR, fatty acid synthesis, essential fatty acids, ACC regulation