Foundations of metabolism Flashcards
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Foundations of metabolism Flashcards
LQB481 W2 Foundations of metabolism.pdf Flashcards
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What is required by organisms to maintain their function?
Energy, largely stored in ATP, heat, raw materials (mainly carbon), and reducing power from NADH and FADH2 / NADPH.
How do phototrophs acquire energy?
Phototrophs transform light energy into chemical energy.
How do chemotrophs obtain energy?
Chemotrophs obtain chemical energy through oxidation of organic compounds generated by phototrophs.
What is metabolism composed of?
Metabolism is composed of a network of many coupled interconnecting reactions that are regulated by the action of enzymes.
What are metabolites?
Metabolites are the reactants, intermediates, and products of metabolic reactions that are constantly shared and shuttled between different pathways.
Why do we examine a single metabolic pathway in isolation?
To simplify and reduce the complexity of metabolic pathways.
What is the basis for delineating specific metabolic pathways?
The way specific pathways are delineated can be somewhat arbitrary and is often based on tradition rather than chemical logic.
What are catabolic pathways?
Catabolic pathways are metabolic pathways that degrade food molecules, often complex substances, into smaller molecules, gaining useful energy in the process.
What are anabolic pathways?
Anabolic pathways use small molecules and energy created by catabolic degradation to synthesize new complex molecules that form the cells.
What is the significance of oxidation-reduction reactions in cellular energy?
The oxidation of carbon fuels to CO2 represents the most important source of cellular energy, generating ATP as the major energy currency.
What role do carrier molecules play in catabolic pathways?
Energy released during the oxidative breakdown of nutrients is stored in carrier molecules such as ATP and electron carriers like NADPH.
What are activated carrier molecules?
Activated carrier molecules are transporters and donors of energy, electrons, and/or chemical groups in enzymatic reactions.
What are examples of high energy carriers?
High energy carriers include ATP and coenzyme A.
What are examples of electron carriers?
Electron carriers include NADP, NADPH, and FAD/FADH2.
What is adenosine triphosphate (ATP)?
ATP is the universal currency of energy in all cells, releasing energy upon dephosphorylation.
What processes utilize ATP?
ATP is used in cellular processes such as muscle contraction, active transport, signal amplification, and biosynthesis.
How is ATP generated?
ATP is generated by the oxidation of fuel molecules like glucose, fatty acids, and amino acids.
What is the significance of anaerobic conditions for ATP generation?
Anaerobic conditions (absence of oxygen) allow ATP generation in the cytoplasm, primarily using glucose.
What are energy-rich phosphate compounds involved in?
They are involved in the flow of energy through metabolic processes, not just ATP.
Give examples of energy-rich phosphate compounds created in exergonic reactions in the glycolysis pathway.
Phosphoenolpyruvate and 1,3-bisphosphoglycerate.
What process refers to the transfer of high energy phosphate to ADP to form ATP?
Substrate-level phosphorylation.
What must the energy in energy-rich phosphate compounds be in comparison to ATP dephosphorylation to enable ATP formation?
Higher than G -315 kJ mol^-1.
What are low energy phosphate compounds created through?
Phosphate transfer from ATP.
What catalyzes the transfer of energy-rich phosphate groups?
Enzymes named kinases.
What role does phosphocreatine serve in cells, especially in skeletal muscle?
It acts as a rapidly mobilizable high energy reservoir.
Which enzyme is responsible for the reversible phosphorylation of creatine?
Creatine kinase.
What happens to ATP levels during periods of high demand in skeletal muscle cells?
Phosphocreatine donates a phosphate to ADP to regenerate ATP.
What is creatinine, and how is it related to muscle creatine?
Creatinine is a breakdown product of muscle creatine and is excreted by the body at a constant rate.
What is the importance of serum creatinine?
It is used as a diagnostic marker for renal function.
What type of compounds are thioesters, and what is their significance in metabolic pathways?
Thioesters are high energy compounds important for metabolic pathways.