Podcast
Questions and Answers
What is the initial enzyme involved in the production of β-hydroxybutyrate?
What is the initial enzyme involved in the production of β-hydroxybutyrate?
Which organ primarily facilitates oxidative deamination in mammals?
Which organ primarily facilitates oxidative deamination in mammals?
Which cofactor can glutamate dehydrogenase utilize during oxidative deamination?
Which cofactor can glutamate dehydrogenase utilize during oxidative deamination?
What occurs during transamination in amino acid catabolism?
What occurs during transamination in amino acid catabolism?
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What is the key function of proteolytic enzymes in protein metabolism?
What is the key function of proteolytic enzymes in protein metabolism?
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What is the result of oxidation occurring in the body if it happens alone?
What is the result of oxidation occurring in the body if it happens alone?
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Which molecule is primarily generated during the phosphorylation of ADP?
Which molecule is primarily generated during the phosphorylation of ADP?
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What role does adenosine play during a myocardial infarction?
What role does adenosine play during a myocardial infarction?
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Which process couples electron transfer to proton transfer to create an electrochemical gradient?
Which process couples electron transfer to proton transfer to create an electrochemical gradient?
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Which molecules serve as electron carriers in the Electron Transport Chain?
Which molecules serve as electron carriers in the Electron Transport Chain?
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What is the final electron acceptor in the Electron Transport Chain during aerobic respiration?
What is the final electron acceptor in the Electron Transport Chain during aerobic respiration?
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In which cellular component does oxidative phosphorylation primarily occur?
In which cellular component does oxidative phosphorylation primarily occur?
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Which process does NOT produce ATP directly?
Which process does NOT produce ATP directly?
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What is the primary purpose of bioenergetics?
What is the primary purpose of bioenergetics?
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What are the two main categories of metabolism?
What are the two main categories of metabolism?
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How many ATP molecules are produced during aerobic cellular respiration per glucose molecule?
How many ATP molecules are produced during aerobic cellular respiration per glucose molecule?
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Which of the following statements about NADP is true?
Which of the following statements about NADP is true?
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What happens to excess glucose when glycogen stores are full?
What happens to excess glucose when glycogen stores are full?
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What is the correct sequence of phases in aerobic cellular respiration?
What is the correct sequence of phases in aerobic cellular respiration?
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Which substrate is NOT used in gluconeogenesis?
Which substrate is NOT used in gluconeogenesis?
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What characterizes the process of fatty acid oxidation according to aerobic rules?
What characterizes the process of fatty acid oxidation according to aerobic rules?
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How is enthalpy change (ΔH) defined in terms of energy transfer?
How is enthalpy change (ΔH) defined in terms of energy transfer?
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What does the pentose phosphate pathway primarily generate?
What does the pentose phosphate pathway primarily generate?
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What distinguishes oxidation-reduction reactions?
What distinguishes oxidation-reduction reactions?
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Which statement about fatty acid metabolism is true?
Which statement about fatty acid metabolism is true?
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What is the initial step in de novo fatty acid synthesis?
What is the initial step in de novo fatty acid synthesis?
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What role does NADPH play in fatty acid synthesis?
What role does NADPH play in fatty acid synthesis?
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What process converts excess carbohydrates and proteins into fatty acids and triglycerides in the liver?
What process converts excess carbohydrates and proteins into fatty acids and triglycerides in the liver?
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What is a significant role of dietary fats?
What is a significant role of dietary fats?
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How is Acetyl-CoA transported from the mitochondria for fatty acid synthesis?
How is Acetyl-CoA transported from the mitochondria for fatty acid synthesis?
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Which of the following is NOT a product generated from beta oxidation of saturated acyl CoA?
Which of the following is NOT a product generated from beta oxidation of saturated acyl CoA?
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Which of the following hormones is involved in the regulation of lipolysis?
Which of the following hormones is involved in the regulation of lipolysis?
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What is formed from acetyl-CoA when fatty acids undergo ketogenesis?
What is formed from acetyl-CoA when fatty acids undergo ketogenesis?
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What happens during the process of lipolysis?
What happens during the process of lipolysis?
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Which ketone body can be produced spontaneously from acetoacetate?
Which ketone body can be produced spontaneously from acetoacetate?
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What is the primary mechanism through which fatty acyl CoA is degraded in beta oxidation?
What is the primary mechanism through which fatty acyl CoA is degraded in beta oxidation?
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Which enzyme is NOT involved in the lipolysis of triacylglycerol?
Which enzyme is NOT involved in the lipolysis of triacylglycerol?
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What is the main difference between substrate-level phosphorylation and oxidative phosphorylation?
What is the main difference between substrate-level phosphorylation and oxidative phosphorylation?
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Which of the following correctly describes glycolysis?
Which of the following correctly describes glycolysis?
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What is the ultimate fate of lactate produced in muscles during anaerobic conditions?
What is the ultimate fate of lactate produced in muscles during anaerobic conditions?
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In which stage does the oxidation of small molecules occur to provide ATP energy?
In which stage does the oxidation of small molecules occur to provide ATP energy?
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What conditions stimulate glycogenesis in the liver and muscles?
What conditions stimulate glycogenesis in the liver and muscles?
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How does excess Acetyl CoA affect metabolic pathways?
How does excess Acetyl CoA affect metabolic pathways?
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During glycolysis, what characterizes the first set of reactions?
During glycolysis, what characterizes the first set of reactions?
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What results from oxidative decarboxylation in the mitochondria?
What results from oxidative decarboxylation in the mitochondria?
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Study Notes
Metabolic Pathways
- Metabolism is a complex network of interconnected pathways
- Pathways include metabolism of complex carbohydrates, complex lipids, lipids, energy, carbohydrates, nucleotides, amino acids, other amino acids, cofactors and vitamins, and biosynthesis of secondary metabolites
- Biodegradation of xenobiotics is also a part of metabolic pathways
- All these pathways are interconnected
Bioenergetics and Metabolism
- Metabolism is a very complicated network where all pathways are connected
Cellular Respiration
- Describes how organisms acquire and transform energy to perform biological work
- Studies different biological processes that lead to energy production and utilization (e.g., ATP, GTP)
- Metabolism is the sum of chemical reactions to maintain the organism's living state
- Divided into catabolism (breaking down molecules for energy) and anabolism (building compounds needed by the cells). These two processes are coupled
- Metabolism is linked to nutrition and nutrient availability
Cell Macromolecules
- Cell macromolecules include proteins, polysaccharides, lipids, and nucleic acids
- NAD and FAD are hydrogen carriers. NADP is not used for energy metabolism
- Chemical energy produced is stored in ATP, NADH, NADPH, and FADH2
Types of Cell Respiration
- Aerobic respiration utilizes oxygen to produce 30 ATP molecules per glucose molecule
- Anaerobic respiration does not use oxygen; produces only 2 ATP molecules per glucose molecule, using inorganic molecules as oxidants
- Glycolysis, TCA cycle, and electron transport chain are phases of aerobic cell respiration
Entropy
- Measure of a system's thermal energy unavailable for useful work per unit temperature
- Heat production is associated with entropy
Enthalpy
- State function determined by internal energy, pressure, and volume
- Simplifies energy transfer descriptions
- Under standard conditions, enthalpy changes equal energy transferred from the environment through heating or work, excluding expansion work
- Measured as enthalpy change (ΔH)
- ΔH is positive in endothermic reactions and negative in exothermic processes
Redox Reactions
- Chemical reactions where oxidation numbers change due to electron gain or loss
- Coupled oxidation reactions with reduction in many biological processes
- Oxidation is loss of electrons; reduction is gain of electrons
- Electrons, protons, and hydrogen ions are associated with redox reactions
High Energy Phosphate
- ATP formed by adding phosphate to ADP (phosphorylation)
- ATP releases phosphate ions to provide energy for cellular metabolism; ADP reappears
- ADP can further release phosphate to generate AMP or non-phosphorylated adenosine in response to urgent oxygen need (e.g., myocardial infarction)
- This process increases vasodilation
Oxidative Phosphorylation
- ATP formed as a result of electron transfer
- Electrons transfer from NADH or FADH2 to O2 through a series of electron carriers in the electron transport chain
- The energy from these redox reactions is captured as a proton gradient
- Chemiosmosis, a proton-dependent process for ATP synthesis
- Mitochondria are the major site of ATP production in aerobic organisms
Electron Transport Chain
- Series of complexes transferring electrons from electron donors to acceptors via redox reactions
- Electron transfer couples with proton transfer (H+ ions) across membrane
- Creates an electrochemical proton gradient driving ATP synthesis
- ETC components include peptides, enzymes, and other molecules
- The final electron acceptor in aerobic respiration is O2 (oxygen)
Substrate Level Phosphorylation
- Direct phosphorylation of ADP with phosphate from a coupled reaction
- ATP generated from the oxidation of NADH and FADH2, and the subsequent electron transfer and proton pumping
- ATP is directly generated, unlike oxidative phosphorylation
Carbohydrates Metabolism
- Stage 1: Digestion and hydrolysis break down large carbohydrates into smaller molecules that enter the bloodstream
- Stage 2: Degradation breaks down the smaller molecules into two- and three-carbon compounds
- Stage 3: Oxidation of small molecules in the citric acid cycle and electron transport, generating ATP energy
Glycolysis
- Metabolic pathway degrading glucose to pyruvate (six-carbon to three-carbon molecule)
- Anaerobic process occurring in the cytoplasm
- Divided into 2 stages:
- Stage A: Reaction steps that consume energy
- Stage B: Reaction steps that produce energy
TCA Cycle (Krebs Cycle)
- Requires oxygen, occurring within aerobic organisms
- Oxidation of Acetyl-CoA to CO2 and Chemical energy, producing energy in the form of ATP. This process happens in the mitochondria
- Key process in extracting energy from carbohydrates, fats, and amino acids.
Glycogenesis
- Process for storing glucose by converting it into glycogen in the liver and muscles
- Occurs when high levels of glucose-6-phosphate are produced during glycolysis
- Doesn't happen when glycogen stores are full or when energy stores are sufficient. Additional glucose is converted to fat
Glycogenolysis
- Process of breaking down glycogen to glucose in the liver and muscles
- Occurs when blood glucose levels drop below 70mg%
- Glucose-1-phosphate is a product
Gluconeogenesis
- Generation of glucose from non-carbohydrate substrates (e.g., amino acids, lipids)
- Occurs when glycogen stores are depleted.
- Occurs in starvation or diabetes, when the body cannot use glucose
Pentose Phosphate Pathway (PPP)
- Parallel metabolic pathway to glycolysis
- Generates NADPH and pentoses (e.g., ribose-5-phosphate)
- Important for nucleotide synthesis
- Also involved in fatty acid biosynthesis
Lipid Metabolism
- Synthesis and degradation of lipids, including fat breakdown or storage for energy
- Lipids obtained from consuming food or produced by the liver
- Minimal amount of essential fat needed in the diet. Essential fatty acids are critical for synthesis.
- Fat soluble vitamins are also absorbed
- Fatty acids can generate 9.1 calories per gram
- End products include carbon dioxide (CO2), water (H2O), and ATP
- Complete combustion requires glucose for conversion and avoids ketone production
Lipolysis
- Breakdown of triglycerides into fatty acids and glycerol
- Released fatty acids in blood, used by other tissues for beta-oxidation and ATP production, and may be re-esterified back into intracellular triglycerides
- Process regulated by autonomic nervous system and hormones (e.g., catecholamines)
Beta Oxidation of Fatty Acids
- Degrading saturated fatty acyl-CoA
- Repeated four-step reaction cycle
- Shortens the fatty acyl chain by two carbons
- Produces FADH2, NADH, and acetyl-CoA
Ketogenesis
- Process producing ketone bodies from fatty acids and ketogenic amino acids when the body cannot use glucose
- Ketone bodies include acetoacetate and β-hydroxybutyrate, also acetone. These are energy sources
- These are produced when the body needs energy and glucose isn't available
Protein Metabolism
- Proteins too large for absorption, are broken down into amino acids through proteolytic enzymes
- Enzymes produced by stomach, pancreas, and small intestine
- Amino acids are absorbed and utilized or converted to other molecules (e.g. , glucose, glycogen, fatty acids)
Amino Acid Catabolism
- First phase involves removing the α-amino groups, producing ammonia
- The carbon skeletons are then further metabolized via central pathways.
- Occurs in two phases, with transamination in the initial phase, followed by oxidative deamination in a further reaction, to produce urea or other catabolic products.
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Description
Explore the intricate network of metabolic pathways and their connection to bioenergetics. This quiz covers the metabolism of carbohydrates, lipids, amino acids, and more, delving into cellular respiration and energy transformation in biological systems. Understand how catabolism and anabolism interplay to maintain life.
