Chapter3 Essential Concepts

Chapter3 Essential Concepts - energy that could be used to...

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Essential Concepts Laws of Thermodynamics govern behavior of cells Primary source of energy for most living organisms is the sun, plants use photosynthesis to make food, animals eat other living things to get food There are hundreds of chemical reactions that occur in the cell and these are organized in pathways where the product od one is the reactant for the next
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There are two major kinds of pathways Catabolic pathways break down complex molecules and release energy (ex. respiration) Anabolic pathways generate the many complex molecules needed by the cell and these require energy input (ex. biosynthesis of macromolecules) Anabolic pathways are coupled to catabolic pathways, which provide both building blocks and energy for biosynthesis Molecules have a certain amount of free energy (G) –
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Unformatted text preview: energy that could be used to do work • Chemical reactions occur with some change in free energy (delta G) Essential Concepts Essential Concepts • Spontaneous reactions have a negative delta G, release energy, increase disorder • Energetically unfavorable reactions ( nonspontaneous ) have a positive delta G, absorb energy, decrease disorder – they do not occur unless coupled with a spontaneous reaction • Coupling occurs via high energy carrier molecules – the major one is ATP • A phosphate is transferred from ATP to activate an intermediate, allowing the reaction to occur • ATP is used to create high energy (phosphorylated) forms of each subunit in the biosynthesis of macromolecules such as proteins and polysaccharides...
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Chapter3 Essential Concepts - energy that could be used to...

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