exam 1c Flashcards
(19 cards)
catabolic pathway
breaks down food molecules into smaller molecules, thereby generating both a useful form of energy for the cell and some for building blocks for biosynthesis
anabolic pathway
use the energy harnessed by catabolism to drive the synthesis of the many molecules that form the cell
second law of thermo
disorder increases, reversing this natural tendency towards disorder requires an intentional effort and input of energy
understand entropy
measure of systems disorder. the greater the disorder, greater the entropy
1st stage of photosynthesis
energy from sunlight is captured and transiently stored as chemical-bond energy in specialized molecules called activated carriers. All of the oxygen in the air we breathe is generated by the splitting of water molecules during the first stage of photosynthesis
2nd stage of photosynthesis
the activated carrier are used to help drive a carbon-fixation process, in which sugars are manufactured from carbon dioxide gas. In this way, photosynthesis generates an essential source of stored chemical-bond energy and other organic materials- for the plant itself and for any animals that eat it
cell respiration
A cell is able to obtain energy from sugars or other organic molecules by allowing the carbon and hydrogen atoms in these molecules to combine with oxygen- that is, become oxidized- to produce CO2 and H2O, respectively
Understand how carbon dioxide is reduced to methane, and methane is oxidized to carbon dioxide
Although the term oxidation literally means the addition of oxygen atoms to a molecule, oxidation is said to occur in any reaction in which electrons are transferred between atoms. Oxidation, in this sense, involves the removal of electrons from an atom. The converse reaction, called reduction, involves the addition of electrons to an atom
free energy
amount of energy in a system that can do useful work (or to cause specific physical or chemical changes) at constant volume and pressure
Free energy change
constant pressure, volume, and temperature, the free energy change of a system is dependent on the free energies of the product and the reactants. P-R
chemical reactions proceed in the direction that
cause a loss of free energy
energetically favorable reactions
those that create disorder in the universe by deceasing the free energy system to which they belong
unfavorable reactions?
create order in the universe; they have a positive ∆G. Such reactions can not occur spontaneously; they take place only when they are coupled to a second reaction with a negative ∆G large enough that the net ∆G of the entire process is negative
enzymes speed up the reaction rate by
lowering activation energy
difference between delta G and delta G naught
delta G naught is at standard conditions
equilibrium constant K
product/reactant, expresses the relationship between products and reactants of a reaction at equilibrium
activated carrier
store and energy in a form that cells can use
ATP as an activated carrier
ATP is made unstable by the three adjacent negative charges in its phosphate tail, which “want” very badly to get further away from each other. The bonds between the phosphate groups are called phosphoanhydride bonds, also referred to as “high-energy bonds.
When required, ATP gives up this energy packet in an energetically favorable hydrolysis to ADP and inorganic phosphate (Pi). The regenerated ADP is then available to be used for another round of the phosphorylation reaction that forms ATP, creating an ATP cycle in the cell.
NADPH/NADP as activated carriers
Both NADH and NADPH carry energy in the form of two high-energy electrons plus a proton (H+), which together form a hydride ion (H-). When these activated carriers pass their hydride ion to a donor molecule, they become oxidized to form NAD+ and NADP+, respectively.
