Podcast
Questions and Answers
What is the primary energy carrier molecule in the body?
What is the primary energy carrier molecule in the body?
- Creatine Phosphate
- Glycogen
- ATP (correct)
- Glucose
What does the term 'anabolism' refer to?
What does the term 'anabolism' refer to?
- The regulation of energy intake and expenditure
- The synthesis of complex molecules from simpler ones (correct)
- The breakdown of complex molecules into simpler ones
- The process of converting food into energy
Which of the following is NOT a characteristic of metabolism?
Which of the following is NOT a characteristic of metabolism?
- It is identical in all individuals. (correct)
- It is involved in maintaining life processes.
- It involves chemical reactions in the body.
- It is affected by food intake and energy expenditure.
Which of the following is an example of a catabolic process?
Which of the following is an example of a catabolic process?
What is the role of allosteric regulation in enzyme activity?
What is the role of allosteric regulation in enzyme activity?
How does the first law of thermodynamics relate to energy balance in the human body?
How does the first law of thermodynamics relate to energy balance in the human body?
Which of the following is NOT a component of energy expenditure?
Which of the following is NOT a component of energy expenditure?
What is the role of transcription in the regulation of metabolism?
What is the role of transcription in the regulation of metabolism?
Which of the following is NOT a characteristic of Complex I in the electron transport chain?
Which of the following is NOT a characteristic of Complex I in the electron transport chain?
What is the primary role of Complex II (succinate dehydrogenase) in the electron transport chain?
What is the primary role of Complex II (succinate dehydrogenase) in the electron transport chain?
Which of the following statements about the Q-cycle is TRUE?
Which of the following statements about the Q-cycle is TRUE?
What is the function of the heme groups in Complex IV (cytochrome c oxidase)?
What is the function of the heme groups in Complex IV (cytochrome c oxidase)?
Which of the following is a CORRECT pairing of an ETC inhibitor and its primary target?
Which of the following is a CORRECT pairing of an ETC inhibitor and its primary target?
What is the main difference between simple and complex carbohydrates, in terms of their effect on blood sugar levels?
What is the main difference between simple and complex carbohydrates, in terms of their effect on blood sugar levels?
Which of the following statements about glycogen is TRUE?
Which of the following statements about glycogen is TRUE?
Which of the following statements about glucose homeostasis is TRUE?
Which of the following statements about glucose homeostasis is TRUE?
Which of the following statements accurately describes the difference between glycogen and amylose?
Which of the following statements accurately describes the difference between glycogen and amylose?
Which enzyme is responsible for the initial step in glycogenolysis, the breakdown of glycogen into glucose-1-phosphate?
Which enzyme is responsible for the initial step in glycogenolysis, the breakdown of glycogen into glucose-1-phosphate?
What is the role of pyridoxal phosphate in glycogen phosphorylase?
What is the role of pyridoxal phosphate in glycogen phosphorylase?
Which of the following statements correctly describes the fate of glucose-6-phosphate produced from glycogenolysis in muscle cells?
Which of the following statements correctly describes the fate of glucose-6-phosphate produced from glycogenolysis in muscle cells?
Which of the following enzymes is responsible for the isomerization of glucose-1-phosphate to glucose-6-phosphate during glycogenolysis?
Which of the following enzymes is responsible for the isomerization of glucose-1-phosphate to glucose-6-phosphate during glycogenolysis?
Which of the following statements correctly describes the allosteric regulation of glycogen phosphorylase by AMP?
Which of the following statements correctly describes the allosteric regulation of glycogen phosphorylase by AMP?
Which of the following is the rate-limiting step of glycolysis?
Which of the following is the rate-limiting step of glycolysis?
Which of the following statements correctly describes the role of glucose-6-phosphatase in the liver?
Which of the following statements correctly describes the role of glucose-6-phosphatase in the liver?
Which of the following tissues can contribute to blood glucose levels by breaking down glycogen?
Which of the following tissues can contribute to blood glucose levels by breaking down glycogen?
Which of the following is a consequence of triose phosphate isomerase deficiency?
Which of the following is a consequence of triose phosphate isomerase deficiency?
Which of the following is NOT a factor affecting Basal Metabolic Rate (BMR)?
Which of the following is NOT a factor affecting Basal Metabolic Rate (BMR)?
Which of the following macronutrients has the highest thermic effect?
Which of the following macronutrients has the highest thermic effect?
What is the main function of the enzyme hexokinase in glycolysis?
What is the main function of the enzyme hexokinase in glycolysis?
Which of the following is a characteristic of substrate-level phosphorylation?
Which of the following is a characteristic of substrate-level phosphorylation?
Which of the following accurately describes the energy status of a cell with high ATP:ADP and NADH:NAD+ ratios?
Which of the following accurately describes the energy status of a cell with high ATP:ADP and NADH:NAD+ ratios?
Which of the following is NOT a component of total energy expenditure?
Which of the following is NOT a component of total energy expenditure?
Which method of measuring energy balance relies on measuring the gases produced during metabolism?
Which method of measuring energy balance relies on measuring the gases produced during metabolism?
What is the function of porins in the outer mitochondrial membrane?
What is the function of porins in the outer mitochondrial membrane?
Where does the TCA cycle take place within the cell?
Where does the TCA cycle take place within the cell?
What is the primary function of the enzyme phosphofructokinase-1 (PFK-1) in glycolysis?
What is the primary function of the enzyme phosphofructokinase-1 (PFK-1) in glycolysis?
Which of the following statements accurately describes the chemical reaction involving NAD and NADH?
Which of the following statements accurately describes the chemical reaction involving NAD and NADH?
Which of the following is a byproduct of muscle protein degradation when the body is in a state of energy deficit?
Which of the following is a byproduct of muscle protein degradation when the body is in a state of energy deficit?
What is the primary function of the enzyme triose phosphate isomerase in glycolysis?
What is the primary function of the enzyme triose phosphate isomerase in glycolysis?
Which of the following is a characteristic of the inner mitochondrial membrane?
Which of the following is a characteristic of the inner mitochondrial membrane?
What is the main source of energy for muscle contraction during the initial stages of exercise?
What is the main source of energy for muscle contraction during the initial stages of exercise?
Which of the following methods is commonly used to measure body composition and differentiate between lean mass and fat mass?
Which of the following methods is commonly used to measure body composition and differentiate between lean mass and fat mass?
During the oxidation of succinate to fumarate, which of the following occurs?
During the oxidation of succinate to fumarate, which of the following occurs?
In the electron transport chain, which complex directly receives electrons from NADH?
In the electron transport chain, which complex directly receives electrons from NADH?
What is the primary function of the chemiosmotic theory in the context of ATP production?
What is the primary function of the chemiosmotic theory in the context of ATP production?
Which molecule serves as a mobile electron carrier, transporting electrons from Complexes I and II to Complex III in the electron transport chain?
Which molecule serves as a mobile electron carrier, transporting electrons from Complexes I and II to Complex III in the electron transport chain?
Which of the following enzymes is NOT involved in the citric acid cycle?
Which of the following enzymes is NOT involved in the citric acid cycle?
Which of the following correctly describes the role of FADH2 in the electron transport chain?
Which of the following correctly describes the role of FADH2 in the electron transport chain?
What is the net ATP yield per molecule of acetyl-CoA that enters the citric acid cycle?
What is the net ATP yield per molecule of acetyl-CoA that enters the citric acid cycle?
Which of the following statements accurately describes the role of the iron-sulfur clusters in the electron transport chain?
Which of the following statements accurately describes the role of the iron-sulfur clusters in the electron transport chain?
During beta oxidation, the fatty acyl-CoA is shortened by how many carbons in each cycle?
During beta oxidation, the fatty acyl-CoA is shortened by how many carbons in each cycle?
What is the name of the enzyme that catalyzes the hydration reaction in beta oxidation?
What is the name of the enzyme that catalyzes the hydration reaction in beta oxidation?
Which of the following molecules is NOT directly involved in electron transport in the electron transport chain?
Which of the following molecules is NOT directly involved in electron transport in the electron transport chain?
Where does beta oxidation occur in the cell?
Where does beta oxidation occur in the cell?
Which of the following is a key difference between NADH and FADH2 in the electron transport chain?
Which of the following is a key difference between NADH and FADH2 in the electron transport chain?
What is the role of cytochrome c in the electron transport chain?
What is the role of cytochrome c in the electron transport chain?
Which of the following is a TRUE statement about the reduction potential of electron carriers in the electron transport chain?
Which of the following is a TRUE statement about the reduction potential of electron carriers in the electron transport chain?
What is the primary function of the proton gradient established across the inner mitochondrial membrane?
What is the primary function of the proton gradient established across the inner mitochondrial membrane?
Which enzyme is responsible for the formation of 1,3-bisphosphoglycerate?
Which enzyme is responsible for the formation of 1,3-bisphosphoglycerate?
What is the net gain of ATP molecules produced during glycolysis?
What is the net gain of ATP molecules produced during glycolysis?
What is the role of NAD+ in glycolysis?
What is the role of NAD+ in glycolysis?
Which of the following statements is TRUE about the TCA cycle?
Which of the following statements is TRUE about the TCA cycle?
Which molecule is a direct product of the enzyme pyruvate kinase?
Which molecule is a direct product of the enzyme pyruvate kinase?
Flashcards
Metabolism
Metabolism
Set of chemical reactions in the body that sustain life; includes enzymatic reactions, influenced by intake and expenditure.
ATP
ATP
Primary energy carrier in living cells, consists of 3 phosphate groups, ribose sugar, and adenine nucleotide.
Anabolism
Anabolism
Process of synthesizing complex molecules from simpler ones, requiring energy (ATP).
Catabolism
Catabolism
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Metabolic regulation
Metabolic regulation
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Central dogma of DNA
Central dogma of DNA
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Allosteric regulation
Allosteric regulation
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First law of thermodynamics
First law of thermodynamics
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Glyceraldehyde-3-phosphate (G3P) oxidation
Glyceraldehyde-3-phosphate (G3P) oxidation
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Substrate-level phosphorylation
Substrate-level phosphorylation
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Enzyme: Phosphoglycerate kinase
Enzyme: Phosphoglycerate kinase
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Phosphoenolpyruvate (PEP) formation
Phosphoenolpyruvate (PEP) formation
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Net glycolysis balance
Net glycolysis balance
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Basal Metabolism
Basal Metabolism
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Thermal Effect of Food
Thermal Effect of Food
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Energy Balance
Energy Balance
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Macronutrients
Macronutrients
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Micronutrients
Micronutrients
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Glycogen Spillover
Glycogen Spillover
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Resting Energy Expenditure (REE)
Resting Energy Expenditure (REE)
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ATP Hydrolysis
ATP Hydrolysis
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Oxidation-Reduction Reactions
Oxidation-Reduction Reactions
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NAD/NADH Ratio
NAD/NADH Ratio
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Glycolysis
Glycolysis
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TCA Cycle
TCA Cycle
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Coenzymes
Coenzymes
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Primary Function of Creatine
Primary Function of Creatine
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Complex I
Complex I
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Complex II
Complex II
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Q-cycle
Q-cycle
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Complex IV
Complex IV
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Hypoglycemia
Hypoglycemia
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Glucogenesis
Glucogenesis
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Fatty liver disease stages
Fatty liver disease stages
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Simple carbohydrates
Simple carbohydrates
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Formation of Citrate
Formation of Citrate
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Isomerization of Citrate
Isomerization of Citrate
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Isocitrate Dehydrogenase
Isocitrate Dehydrogenase
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Alpha-Ketoglutarate Dehydrogenase
Alpha-Ketoglutarate Dehydrogenase
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Succinyl-CoA Synthetase
Succinyl-CoA Synthetase
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Succinate Dehydrogenase
Succinate Dehydrogenase
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Fumarase
Fumarase
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Malate Dehydrogenase
Malate Dehydrogenase
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Net Balance of TCA Cycle
Net Balance of TCA Cycle
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Beta Oxidation
Beta Oxidation
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Activation of Fatty Acids
Activation of Fatty Acids
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Chemiosmotic Theory
Chemiosmotic Theory
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Three Types of Electron Transfer
Three Types of Electron Transfer
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Role of Coenzyme Q
Role of Coenzyme Q
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Complex I Function
Complex I Function
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Amylose
Amylose
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Glycogen
Glycogen
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Glycogenolysis
Glycogenolysis
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Glycogen phosphorylase
Glycogen phosphorylase
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Phosphoglucomutase
Phosphoglucomutase
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Glucose-6-phosphate (G6P)
Glucose-6-phosphate (G6P)
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Liver's G6P function
Liver's G6P function
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Glucose-6-phosphatase
Glucose-6-phosphatase
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Rate limiting step of glycolysis
Rate limiting step of glycolysis
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Fates of Pyruvate
Fates of Pyruvate
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Study Notes
Macronutrients and Energy Balance
- Metabolism is a set of chemical reactions sustaining life; enzymatic reactions.
- Affected by food intake, energy expenditure, and varies by individual.
- Macronutrients are essential for energy production, creating ATP, the primary energy carrier.
- ATP has three phosphate groups, ribose sugar, and adenine, with multiple energy-releasing reactions.
- It transfers energy throughout cell compartments without carrier assistance.
- Metabolic regulation maintains anabolic and catabolic processes for homeostasis.
- Anabolism synthesizes complex molecules from simpler ones, requiring ATP.
- Catabolism breaks down molecules, releasing energy.
- External stressors affect metabolism.
- Maintaining nutrient balance (excess or inadequate intake) is vital for cellular function.
- Eating is a stressor requiring short-term and long-term regulation through different responses (hours vs. weeks).
- Regulation begins at the cellular level, involving transcription, translation, and post-translational/transcriptional steps.
Metabolic Regulation with Central Dogma
- The central dogma in metabolic regulation is DNA → mRNA → protein (transcription & translation).
- DNA is transcribed to mRNA by RNA polymerase.
- mRNA is processed; includes exons (coding) and introns (non-coding).
- mRNA is then translated into amino acid chains to form proteins.
- All these processes must occur simultaneously & quickly for rapid responses (hormone triggers).
- Allosteric regulation occurs on an enzyme; the substrate binds away from the active site and inhibits/enhances enzyme activity (often involved in feedback loops).
Energy Balance and Thermodynamics
- Energy balance is tightly regulated, crucial for proper body function.
- The first law of thermodynamics states energy is conserved, not created or destroyed; it can be transformed.
- Energy balance is when energy intake (food/alcohol) matches energy expended in basal metabolism, thermic effect of food, and physical activity.
- Basal metabolism accounts for 70% of energy expenditure (resting), 10% is the thermic effect of food, and 20% from physical activity.
- Energy intake equals energy expenditure for maintaining weight.
- Macronutrients are the main calorie source (carbohydrates, protein, lipids).
Macronutrient Thermic Effects
- Macronutrients have varying thermic effects, affecting calorie storage.
- Alcohol has a 15% thermic effect, 7 cal/gram, storing 85% of calories.
- Exogenous ketones have a 3% thermic effect, 4 cal/gram, storing 97% of calories.
- Protein has a 25-30% thermic effect, 4 cal/gram, with 70-75% calorie storage.
- Carbohydrates have a 7-10% thermic effect, 4 cal/gram, and store 90% of calories.
- Glycogen spillover involves storing excess carbohydrates; 15-20% thermic effect, 4 cal/gram, and stores 80% of calories.
- Fat has a 3% thermic effect, 9 cal/gram, storing 97% of calories.
- Glycogen spillover occurs when excessive carbohydrates are consumed, stored as glycogen.
Measuring Energy Expenditure
- Resting energy expenditure (REE), often measured as resting metabolic rate (RMR), is the energy needed for metabolism at rest.
- Accounts for 70% of energy use in some sedentary individuals.
- It is measured during sleep and is 5% higher when awake (varies by activity).
- Factors affecting RMR include age, body size and composition, physical activity, hormones, genetics, diet, sleep, stress, illness, and drugs.
- Thermogenesis is heat production due to external temperature changes (cold – shivering, heat – sweating).
- Energy expenditure is measured by indirect calorimetry (measuring gases), dual-energy X-ray absorptiometry (DEXA) (measures lean and fat mass), and self-reporting or surveys.
ATP and Energy
- ATP has two high-energy phosphoanhydride bonds (releasing 7.3 kcal each during hydrolysis).
- Hydrolysis results in a release of energy.
- Muscles use phosphocreatine as an energy reserve (substrate level phosphorylation – no oxygen needed).
- Oxidation-reduction reactions involve electron transfer (donor loses, acceptor gains). NAD+ and FAD are involved; NAD becomes NADH (reduced) while FAD becomes FADH2 (reduced).
Mitochondrial Structure and Cell Energy Status
- Mitochondria have an outer (permeable) and inner (impermeable) membrane.
- Mitochondrial matrix has a negative charge.
- High ATP to ADP and NADH:NAD+ ratios mean excess energy; stored as adipose tissue (lipogenesis).
- Low ratios mean cell lacks energy and turns to fat stores for glucose (lipolysis and gluconeogenesis).
Macronutrient Oxidation
- Glycolysis occurs in cytoplasm, breaking down glucose for ATP.
- The TCA cycle occurs in mitochondria, oxidizing acetyl-CoA to CO2.
- The TCA cycle generates NADH, FADH2, and ATP; 10 ATP for two turns.
- Beta-oxidation is the primary fatty acid catabolism pathway, converting long-chain fatty acids into ATP in mitochondria.
- Acetyl-CoA from beta-oxidation enters TCA.
- Fatty acids activated into fatty acyl-CoA (in cytosol) for beta-oxidation.
Electron Transport Chain and Oxidative Phosphorylation
- Electron transport chain (ETC) uses electrons from reduced coenzymes to produce a proton gradient across the inner mitochondrial membrane.
- The gradient powers ATP synthesis (oxidative phosphorylation) via Chemiosmotic theory that is established across a membrane.
- The ETC has four protein complexes, ubiquinone (Coenzyme Q) and cytochrome C.
- Each complex has redox centers: flavoproteins, cytochromes, iron-sulfur clusters (electron transfer). Ubiquinone is a mobile electron transporter, transferring electrons and protons between complexes.
- Complexes I, III, and IV are proton pumps.
- Complex II is not a proton pump.
- Complex IV reduces oxygen to water, using electrons from protein complexes.
Carbohydrate Metabolism and Glucose Homeostasis
- Body needs stable glucose for functions (90-126 mg/dL fasting blood glucose is normal).
- Liver's main role is maintaining BG levels and output.
- Glycogenolysis is the breakdown of glycogen to glucose.
- Glycogenesis makes glycogen and liver glycogen is important for blood sugar.
- Key enzymes are glycogen phosphorylase and glucose-6-phosphatase (only found in the liver).
- Muscle and adipose tissue lack glucose-6-phosphatase; thus, their glycogen doesn't contribute significantly to blood sugar.
Glycolysis Steps
Glycolysis has ten steps converting glucose to pyruvate. Relevant enzymes and overall products are noted above.
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Description
Explore the fundamentals of metabolism and its relationship with macronutrients in this insightful quiz. Learn about how energy balance impacts cellular function and the intricate processes of anabolism and catabolism. This quiz will help you understand the regulatory mechanisms that govern metabolic health.
