Energy Flashcards by Shelby Harrington

how is energy created/use in the body

metabolism

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what is metabolism carried out by

enzymes

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what is anabolism

metabolic process that builds complicated molecules from simple ones

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what is catabolism

metabolic process of breaking down complex molecules into simpler compounds

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which molecules are richer in energy

complex molecules due to multiple bonds

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what is thermodynamics

describes energy and its transformation by describing things as a system and its surroundings

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biological systems are what kinds of system

open, it exchanges matter and energy with surroundings

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what is the first law of thermodynamics

energy cannot be created or destroyed, only transferred and transformed

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what is the second law of thermodynamcis

energy and matter move from order to disorder over time
the (entropy in) universe is constantly increasing

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what is entropy

the amount/level of disorder

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what is low entropy in terms of potential energy

low entropy means it is organized with high potential energy

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what is high entropy in terms of potential energy

high entropy means it is disorganized with low potential energy

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how can biological systems be ordered but still follow the second law of thermodynamics

cells borrow entropy from somewhere else and decrease entropy locally, but entropy in surrounding increases due to energy and disordered molecules being released into environment

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what is Gibbs free energy

the amount of energy of a system available to do work

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what is the free energy equation and symbol meaning

G= H-TS
H= enthalpy (total heat energy)
T= temperature
S=entropy

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what is an exergonic reaction (in terms of G)

negative G (Gibbs free energy), the system loses free energy (can mean increased entropy than what we started with)

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what is an endergonic reaction (in terms of G)

positive G (Gibbs free energy), system gains free energy (can mean increased enthalpy)

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what is a spontaneous reaction

a chemical reaction that will go on its own without any outside influence, often exothermic

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what is an exergonic reaction

an energy releasing chemical reaction yielding products that contain less potential energy that the reactants

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what is an endergonic reactions

energy requiring chemical reaction yielding products rich in potential energy

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what is an energy coupling reaction

the use of energy released from an exergonic reaction used to drive essential endergonic reactions, requires an enzyme

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what is the energy of activation

the amount of energy that reactants must absorb before a chemical reaction will start
an energy barrier preventing molecules form breaking down spontaneously

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effect of enzyme of energy of activation barrier

can lower the amount of energy required

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what is an endothermic reactions

transformations that result in a system taking up heat form its surroundings

what is an exothermic reaction

transformations that release heat

difference between exergonic and exothermic

EXOTHERMIC DOES NOT MEAN EXERGONIC exergonic- Gibbs free energy being negative exothermic- change in enthalpy, heat released

what is ATP

the energy currency/shuttle of the living cell

structure of ATP

nucleotide consisting of: Adenine- nitrogen containing organic base Ribose- five carbon sugar three phosphate atoms surrounded by oxygen atoms

function of ATP (4)

- hydrolysis of ATP (exergonic reaction) favors the formation of products in living cells - donates energy through the transfer of the phosphate group - nearly all cellular work depends on ATP energizing other molecules using phosphorylation - reaction can also be coupled to endergonic reactions in cells

two ways to create ATP

substrate level phosphorylation, chemiosmosis

substrate level phosphorylation of ATP

formed when phosphate group is transferred to ADP from a phosphorylated intermediate

what is chemiosmosis

process by which phosphorylation of ADP to form ATP is coupled to transfer of electrons down an electron transport chain

what is oxidative phosphorylation

ATP synthesis driven by electron transfer of oxygen

what is photophosphorylation

ATP synthesis driven by light

where is energy stored in cells

chemical bonds of lipids, starch, and glycogen and energy for immediate use is stored in ATP

what are enzymes

a protein that serves as a biological catalyst

what enzymes do to the equilibrium

allows it to be approached faster

true or false: enzymes change after they act as a catalyst

false, they remain unchanged

what is the active site of an enzyme

region on the surface of an enzyme where the substrate binds, where catalysis occurs

how enzymes cause catalysis (3)

- bring reacting molecules together - expose reactant molecules to altered change environments that promote catalysis - change the shape of substrate molecules

how do temp and pH affect enzymes

enzymes have an optimal temp. and pH where they act at peak efficiency (pH usually near cellular contents, pH 7)

what is an enzyme cofactor

nonprotein group that binds to an enzyme, is necessary for catalysis to occur

what are cofactors

often metallic ions

what are coenzymes

organic molecules

what do reactions depend on

concentration

what happens when substrate is low

reaction rate slows and the enzyme and substrates collide infrequantly

what happens when substrate is high

enzymes become saturated with reactants, rate of reactions increase and then level off

what is enzyme inhibition

a non-substrate molecules that can bind to an enzyme and decrease its activity

what is competitive inhibition

the inhibitor competes with the normal substrate for the active site

what is non-competitive inhibition

when the inhibitor does not compete with the normal substrate for the active site but combines with sites elsewhere in the enzyme

what is feedback inhibition

a type of metabolic regulation where the product of a reaction inhibits tis own synthesis

what are redox reactions

ways for cells to transfer energy through the transfer of electrons, usually with a hydrogen atoms (electron and proton instead of just an electron)

what is oxidation

the process in which a substrate loses electrons, substrate becomes oxidized and gives up energy

what is reduction

process in which a substrate gains an electron, becomes reduces as it receives energy

why is it called a redox reaction

because oxidation and reduction often happen simultaneously

what are acceptor molecules

the molecules that accepts the transferred electron and energy from an organic compound

what are biology carriers

electron carrier

how do bioenergy carriers exist in the body

in reduced states meaning it has more free energy, or an oxidized state meaning it has less energy so it can take or lose electrons

types of bioenergy carriers

NAD+ and NADH FAD and FAD2 cytochromes ubiquinone