Question 1: What is the primary function of the urea cycle in humans? Answer: The urea cycle converts ammonia, a highly toxic byproduct of amino acid metabolism, into urea, a less toxic compound that can be safely excreted in urine. This process is vital for maintaining nitrogen balance in the body. Question 2: Which cellular […]
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Q.1 – Which of the following is a common compound shared by the TCA (Tricarboxylic Acid) cycle and the Urea cycle? A. α-Ketoglutarate B. Succinyl-CoA C. Oxaloacetate D. Fumarate E. Citrate Correct Answer: D. Fumarate Explanation: Fumarate is a key intermediate shared between the TCA and Urea cycles. In the Urea cycle, fumarate is produced
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Question 1: Why are triglycerides a more efficient energy storage form compared to glycogen? Answer: Triglycerides are highly reduced and stored in a nearly anhydrous form, yielding about 9 kcal/g upon complete oxidation. In contrast, the polar nature of glycogen leads to greater hydration, reducing its energy storage capacity to about 1/6th that of fat.
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Question 1: Explain why gluconeogenesis is not simply the reverse of glycolysis. Answer: Gluconeogenesis is not simply the reverse of glycolysis because there are three irreversible reactions in glycolysis that must be bypassed in gluconeogenesis. These irreversible reactions are catalyzed by hexokinase, phosphofructokinase, and pyruvate kinase. Gluconeogenesis uses different enzymes to bypass these steps, making
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Here’s a table showing the amino acids associated with each intermediate and helpful mnemonics to aid memorization: Intermediate Amino Acids Associated Mnemonic for Amino Acid Entry Points Pyruvate Glycine, Alanine, Serine, Cysteine, Threonine, Tryptophan, Hydroxyproline G – Glycine A – Alanine S – Serine C – Cysteine T – Threonine T – Tryptophan H – Hydroxyproline
Amino acids associated with the TCA cycle and their entry points (with easy mnemonics) Read More »
Question 1: Where does fatty acid synthesis primarily occur within the cell? Answer: Fatty acid synthesis occurs in the cytosol of the cell. This is in contrast to fatty acid oxidation, which primarily occurs in the mitochondria. Question 2: What is the primary product of fatty acid synthesis? Answer: The primary product of fatty acid
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Overview of Fatty Acid Metabolism Disorders Disorder Enzyme Defect Impairment Type Clinical Manifestations Mnemonic Medium-Chain Acyl-CoA Dehydrogenase Deficiency (MCAD) Acyl-CoA Dehydrogenase specific for medium-chain fatty acids Impaired beta-oxidation of medium-chain fatty acids Hypoglycemia, lethargy, vomiting, seizures, coma, and sudden infant death MCAD = “Might Collapse And Die” Carnitine Deficiency Carnitine transporter or synthesis defect
Table 1: Role of organelles in Fatty Acid Synthesis, Elongation, and Desaturation Process Organelle Function Key Enzymes/Features De Novo Fatty Acid Synthesis Cytoplasm Formation of palmitate (16-carbon saturated fatty acid) from acetyl-CoA and malonyl-CoA. Acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS) Elongation of Fatty Acids Endoplasmic Reticulum (ER), Mitochondria Extends the carbon chain of long-chain
This table includes a note about the enzyme activity in each state: State Hormone Pathway Enzymes Active Mnemonic Fed State Insulin Glycolysis Hexokinase, PFK-1, Pyruvate Kinase “Hungry Pandas Party” (HPP) Glycogenesis Glycogen Synthase “Glyco Savings” Fatty Acid Synthesis Acetyl-CoA Carboxylase, Fatty Acid Synthase “ACCelerate the Fats” Protein Synthesis Ribosomal enzymes “Ribs Build” Lipogenesis Lipoprotein Lipase
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1. A 45-year-old patient presents to the clinic with significant weight loss and fatigue. Blood tests reveal elevated levels of epinephrine and glucagon. Given this clinical context, when these hormones bind to receptors on the adipose cell membrane, which of the following is NOT expected to occur? A. Fatty acids are activated, enter the mitochondria,
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