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58 Cards in this Set
- Front
- Back
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Metabolism
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total of all of an organisms chemical processes (all the reactions happening in an organism.
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Catabolic pathways
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processes that release energy by breaking down complex molecules into simples ones. I.e. Respiration
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Anabolic pathways
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processes that consume energy to build complex molecules out of simpler ones. I.e. Building proteins from amino acids
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Energy coupling
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energy released from catabolism can be used to drive anabolic pathways
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Bioenergetics
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study of how organisms manage their energy resources
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Energy
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the capacity to do work
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Kinetic energy
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the energy of motion
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What is an example of kinetic energy?
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water through a dam, light powering photosynthesis
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Potential energy
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stored energy due to location or structure
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What is an example of potential energy?
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water behind a dam (before it gets released)
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Chemical energy
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stored in molecules due to arrangement of atoms
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What do energy do with energy?
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transform it
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Thermodynamics
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the study of energy transformers (like organisms)
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Closed system
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system that is isolated from surroundings
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Open system
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system wherein energy can be transferred between system and surroundings
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Are living organisms open or closed systems?
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living organisms are open systems
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First law of thermodynamics
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energy cannot be created or destroyed, but it can be transferred
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Second law of thermodynamics
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every energy transfer increases the entry (disorder/randomness) of the universe
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What happens to part of the energy in most transformations?
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some of the energy is lost as heat (the most random state of energy)
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What is the relationship between the entropy of a system and that of the universe?
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entropy of a system can decrease as long as the entropy of the universe (system and surroundings) increases
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Free energy
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portion of a systems energy that can perform work if the temperature is uniform
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What do delta G, H, S and solitary T stand for in the free energy equation?
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G=free energy, H=total energy, s=entropy and t= temperature (in Kelvin)
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What is the free energy equation?
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G=H-TS, free energy = total energy – Temperature x entropy
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What happens to the free energy of a system during a spontaneous process?
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the free energy decreases
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For a reaction at equilibrium delta G =?
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0
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Exergonic reaction
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a reaction that is releasing energy, energy out –delta G, spontaneous
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What is an example of an exergonic reaction
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cellular respiration
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Endergonic reaction
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absorbs energy from surroundings, +delta G, nonspontaneous reaction
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What is an example of an endergonic reaction?
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photosynthesis (powered by the light energy from the sun)
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Why can’t calls reach metabolic equilibrium
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they would die
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How do cells stop from reaching metabolic equilibrium?
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the product of one reaction becomes a reactant for another reaction. This also stops build up.
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ATP
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source of energy that powers cellular work, adenosine triphosphate
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What is ATP made of?
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adenine + ribose + 3 phosphate
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What are the 3 types of work that cells do?
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mechanical, transport, chemical
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What is an example of mechanical work?
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muscles contractions, movement of chromosomes
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What is an example of transport work?
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pump things across membranes
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What is an example of chemical work?
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pushing endergonic reactions that would not occur spontaneously
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How can bond between phosphate groups be broken and what happens as a result?
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bonds between phosphate break with hydrolysis. It releases energy
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Phosphorylation
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transferring a phosphate to some other molecule to make an endergonic reaction happen.
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How can ATP be regenerated?
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adding Pi to ADP in an endergonic reaction.
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Enzyme
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protein catalyst
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What do enzymes do?
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Speed up a reaction without being consumed
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What is needed to start a reaction?
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free energy
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Why is free energy needed to start a reaction?
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because the bond of the reactants need to be broken
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Why can’t heat (which works) be used to speed up molecules?
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it can kill cells
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How do enzymes speed up a reaction?
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enzymes lower the EA barrier so transition state can be reached without heat (at room temperature)
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How many substrates can each enzyme usually work on?
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very few, usually just one
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What the enzyme progression?
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substrate >>> (with the help of) enzyme) >>> product
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Enzyme names usually end in what?
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-ase
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Active site
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the place in an enzyme where the substrate fits
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What happens when the substrate enters the active site?
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the substrate induces the enzyme to change shape slightly so that it fits better. Induced fit.
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How fast can enzymes work?
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About 1000 molecule/second or more
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How do enzymes break bonds?
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they can stress or twist them
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What 2 things do an active environment have to be more hospitable to the substrate?
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PH, brief covalent bonds with the side chains of the enzymes
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Is more always better with substrates?
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the more substrate the faster the reaction occurs until the saturation point where enough to fill each enzyme (vmax)
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Cofactors
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coenzymes, nonprotien helps
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Optimal environment for enzymes
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the temperature and pH that they like the best
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Temperature does what to enzymes?
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increases the speed of reactions unless its too high in which case things are denatured
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