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58 Cards in this Set

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