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Metabolism: the totality of an organism’s chemical reactions - Coggle…
Metabolism: the totality of an organism’s
chemical reactions
pathways
metabolic pathway: a specific molecule is
altered in a series of steps to produce a product
Catabolic pathways: release energy by breaking
down complex molecules into simpler compounds
Anabolic pathways: consume energy to build
complex molecules from simpler ones
Bioenergetics: the study of how energy flows
through living organisms
Kinetic energy: energy associated with motion
Potential energy: energy that matter possesses
because of its location or structure
Thermal energy: the kinetic energy associated
with random movement of atoms or molecules
Thermal energy in transfer from one object to
another is called heat
Chemical energy: potential energy available for
release in a chemical reaction
Thermodynamics: The study of energy
transformations in a collection of matter
First law of thermodynamic: Energy can be transferred and transformed, but it cannot be created or destroyed
second law of thermodynamics: Every energy transfer or transformation increases the entropy of the universe
Spontaneous processes
Free energy is the portion of a system’s energy that can do work when temperature and pressure are uniform throughout the system, as in a living cell
Reactions
exergonic reaction: proceeds with a net release of free energy to the surroundings
ATP powers cellular work by coupling exergonic reactions to endergonic reactions
A cell does three main kinds of work
Chemical work—pushing endergonic reactions
Transport work—pumping substances across membranes against the direction of spontaneous movement
Mechanical work—such as beating cilia or
contracting muscle cells
endergonic reaction: absorbs free energy from the surroundings
Enzymes: proteins encoded by genes
catalyst: a chemical agent that speeds up a reaction without being consumed by the reaction
enzyme: a macromolecule (typically protein) that acts as a catalyst to speed up a specific reaction
enzyme’s substrate
The enzyme binds to its substrate, forming an enzyme-substrate complex
The enzyme binds to its substrate, forming an
enzyme-substrate complex
Active site is the region on the enzyme, often
a pocket or groove, that binds to the substrate
Cofactors: nonprotein helpers that bind to the enzyme permanently, or reversibly with the substrate
Organic cofactors are called coenzymes
Enzyme Inhibitors: Certain chemicals selectively inhibit the action of specific enzymes
Competitive inhibitors closely resemble the
substrate, and can bind to the enzyme’s active site
Noncompetitive inhibitors bind to another part of
the enzyme, away from the active site
Allosteric regulation: when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site
cooperativity: substrate binding to one active site triggers a shape change in the enzyme that stabilizes the active form for all other sites
feedback inhibition: the end product of a
metabolic pathway shuts down the pathway
prevents a cell from wasting chemical resources by synthesizing more product than is needed