chapter 8 Flashcards
what is a metabolic pathway?
a series of chemical reactions that takes a starting molecule and modifies it through a series of metabolic intermediates, eventually yielding a final product.
what are metabolic pathways composed of?
synthesis (anabolism) and degradation (catabolism)
do chemical reactions of metabolic pathways take place on their own?
no, each step is catalyzed by an enzyme
what are anabolic reactions?
when small molecules combine together to form large molecules
what is an example of an anabolic reaction?
photosynthesis
why do anabolic reactions require energy?
because this process synthesizes an energy storing molecule
what are catabolic reactions?
when a larger molecule breaks down into smaller molecules
what is an example of a catabolic reaction?
cellular respiration
why are energy storage molecules, such as glucose, broken down?
to release energy
what is thermodynamics?
the study of energy and energy transfer regarding physical matter
what is the matter relevant to a particular case of energy transfer called?
a system
what is everything outside of the relevant matter called?
the surroundings
what is an open system?
a system where energy can be exchanged freely with the surroundings
what is a closed system?
a system where energy cannot be exchanged freely with the surroundings
what is the first law of thermodynamics?
the total amount of energy in the world is constant and conserved
what performs one of the most biologically useful energy transformations on earth?
plants!
what is the second law of thermodynamics?
all energy transformations and transfers can never be completely efficient
what is the most common lost form of energy?
heat energy
what kind of energy is lost during metabolic reactions?
heat energy
what are the two types of energy?
kinetic and potential energy
what is kinetic energy?
the energy of motion
what is potential energy?
energy associated with location and structure of matter
what kind of energy is stored in the bonds of food molecules?
potential energy
what is the potential energy stored in chemical bonds called?
chemical energy
what are the two types of reactions?
exergonic and endergonic
what is an exergonic reaction?
reactions that have a negative change in free energy, releasing free energy
