Ground Rules of Metabolism Flashcards
Metabolism-
all of organism’s chemical processes
Participants in a metabolic reaction:
Reactants,Intermediate,Products
Reactants
substances that enter a reaction
Intermediate
any substance that forms during reaction
Products
substances produced or left at the end
Catabolic pathways
processes that release energy by breaking down complex substances into simpler substances
ex catabolic pathways
o Ex- cellular respiration, in which glucose is broken down toCO2 and water, releasing energy
Anabolic pathways-
consume energy to build complex substances from simpler ones
Anabolic pathways- ex
Ex- synthesis of proteins from amino acids
Energy
capacity to do work
Kinetic energy + ex
energy of motion. ex–Water, electrons, leg muscles, light
Potential energy + ex;
stored energy. Water behind a dam
measurement chemical energy
kcal
Chemical energy-
potential energy of molecules stored in bonds
Can energy be converted? Ex?
Energy can be converted from one form to another, ex- respiration turns chemical energy into kinetic energy (then glucose is broken down). Organisms secure energy from their environment and use it to perform energy-required processes.
Types of work performed in cell:
mechanical, transport, chemical
mechanical work
movement–muscle cell contraction, beating of cilia (little hairs in respiratory tract that sweep away dirt and dust caught in mucus)
Transport
active transport/electrochemical work. pumping of substances across membranes against the direction of spontaneous movement
Chemical work
powering reactions that do not occur spontaneously
Thermodynamics-
study of energy transformations that occur in a collection of matter
First Law of Thermodynamics
energy can be transferred and transformed, but it cannot be created or destroyed. Also known as law of conservation of energy`
Second Law of Thermodynamics-
with every energy transfer, entropy, or disorder increases. Energy tends to flow from concentrated to less concentrated forms.
spontaneous-
-reaction that doesn’t require energy
example 1 of SLoT
Example- energy in cells mainly comes from breaking the bonds in organic molecules. However, in every energy transfer, some energy is lost to surroundings as heat and can’t be recaptured
Exergonic reactions
reactions that have net release of G; spontaneous
Ex exergonic reactions
Ex- respiration- breaking down glucose will release energy stored in the sugar molecules (catabolic)
Endergonic reactions-
a reaction that has a positive delta G–requires net input of energy; non spontaneous
Ex endergonic reactions
Ex- photosynthesis (opposite of respiration)- producing sugar by absorbing energy from the sun (anabolic)
Are reactions reversible?
mostly— Most reactions are reversible- can run in forward or reverse direction