Chapter 6 Flashcards
Metabolism
All chemical rxns in cell (catabolic and anabolic)
Bioenergetics, energy flow, through a living system
Catabolic
break down/degradation
release energy
Anabolic
Biosynthesis
absorb energy
carbohydrate metabolism
cellular respiration (catabolic) in animal cells
photosynthesis (anabolic) in plant cells
Cellular respiration
catabolic, breakdown sugar
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
Photosynthesis
anabolic, synthesize sugar
6CO2 + 6H2O + energy -> C6H12O6 + 6O2
energy
ability to do work, bring about change
joules or calories
Important types of energy
Solar (photons)
Chemical (chemical bonds)
mechanical (muscular contraction, cellular movement)
Potential energy
Stored energy
Kinetic energy
Energy of motion
“free” energy
Gibbs free energy Willard Gibbs (1878)
portion of system energy available to preform work at uniform (temp/pressure)
change in G = change in H - (T x change in S)
H = enthalpy ( total energy )
S = entropy (disorder)
T = absolute temp (kelvin)
negative change in G
spontaneous process
change in H negative
Tchange in S very positive
change in G
G final - G initial
more to less free energy
system becomes more stable and energy released can be used
exergonic reactions
“energy outward”
net release
change in G = negative
spontaneous, released E to surroundings
metabolism -> heat
more reactants than products
high to low GFE
Endergonic reactions
“energy inward”
net input
change in G = positive
not spontaneous
requires E from surroundings
coupled with exergonic rxn.s
low to high GFE
Metabolism equilibrium
never at equilibrium
activation energy
energy required to start reaction
High AE -> slows rxn
Low AW -> quickens rxn
Energy and reactions
“contorts” reactants
transition state
allows rxn. to occur
Thermodynamics
Study of energy flow/transfer of physical matter
in a system/environment
1st law of conservation of energy
Energy cannot be created or destroyed, can be transferred/transformed, and can go from one form to another
Thermodynamics does not
Indicate if process is possible, will occur spontaneously, or what conditions are needed for the process
2nd law of thermodynamics
Energy transformations loose useable energy
Every transformation makes the universe less organized/ less organized, more disordered
Entropy
disorder
Universe prefers
entropy/disorder
less energy to be disordered
Relative disorganization
S; disorder; at the end of process there’s less energy and more S
ATP structure
Nucleotide (adenine)
5 carbon sugar (ribose)
= adenosine
3 phosphates (triphosphate
ATP function
Chemical (anabolism)
Transport (protein pumps)
Mechanical (cilia movement)
Coupled reactions
exergonic energy fuels endergonic rxns
Adenosine triphosphate
ATP
energy currency of cells
Hydrolysis rxn -> water cuts P off
Uses ATP to create ADP P and energy
converts to ADP and creates energy
Adenosine diphosphate
ADP
Dehydration rxn. -> produce H2O
glucose degradation
uses energy ADP and P to make ATP
Coupled reactions
one reaction endergonic one exergonic
exergonic (ATP) fuels process
phosphorylation (phosphate transfer) (ADP + P = ATP)
Enzymes
Catalyze metabolic rxns
most require energy input
lower activation energy
enzyme doesnt change
get energy out dont produce energy
makes rxn. more likely to occur
-ase
enzymes
Lock-n-key model
substrate acts as key to specific enzyme
interact via H bonds or ionic bonds
initially thought
Induced fit model
Binding causes confirmation change
interactions close together
enhance catalytic ability
active sites
lower activation energy
template for multiple substrates to combine
R group microenvironment
distort substrate shape and increase reactivity
direct temporary chemical interactions
rate of enzymatic catalysis
Increased concentration of substrate increases rate of reaction to a point
then reaction rates decline and must add more enzyme
temp, pH, cofactors, coenzymes effect
Anabolic reaction
synthesis reaction enzymatic
Catabolic reaction
Degradation reaction enzymatic
Native function and activity
Native shape
effected by change in concentration of substrate, optimal conditions, cofactors, coenzymes
cofactors
inorganic ions required for enzymes role
coenzymes
organic molecules, help enzymes function by combining with them
Inhibitors
Prevent enzyme from operating
competitive and noncompetitive
Competitive inhibitors
bind to active site and prevent substrate from binding
Noncompetitive inhibitors
bind to another site on enzyme which causes the enzyme to change shape so substrate cannot bind
Allosteric activation/inhibition
process when noncompetitive inhibitor bonds to enzyme at secondary site changing function
Activator in allosteric activation
stabilizes function form
Inhibitor in allosteric activation
stabilizes inactive form
Cooperativity in allosteric activation
binding on one side increases likelihood for bonding on another
multi-site enzyme/protein
Feedback inhibition
Reaction halted by product produced by reaction
binds to enzyme
ATP pathways; help save glucose
