Lecture 7- intro to metabolism and energy Flashcards
metabolism=
all of a cell’s chemical reactions
anabolism=
give example
rxn that requires energy to organize the cell (building and moving away from chaos/ disorder)
eg. DNA replication
catabolism=
rxn that release energy from breakdown of nutrients
ATP from ____ rxns drive the energy needs of ___ rxns
catabolic
anabolic
energy=
capacity to cause change or the capacity to work
2 main energy types:
- Potential energy: stored energy due to position or composition (or both)
- Kinetic Energy: energy due to movement (every molecule has a certain degree of kinetic energy)
- eg diffusion
thermodynamics=
*note: cell is a(n) ____ system
- the study of energy transformations
- open
first law of thermodynamics
energy cannot be created nor destroyed (only converted/ transformed from one form to another)
second law of thermodynamics
entropy of the universe is always increasing
entropy= measure of disorder
____ is the most disordered form of energy
heat
rxns will be spontaneous if the disorder of the universe is _____ (inc/decreased).
Why?
- increased
- therefore system becomes more stable (less likely to change)
free energy=
portion of a system’s energy that’s available to perform work
systems with high free energy (complex/ organized) have ____ (high/low) entropy
low
systems with low free energy (disordered/ random) have ____ (high/low) entropy
high (therefore less energy available to do work)
rxns with a negative delta G are ____(spont or not).
= _________ (ender/exergonic)
- example
spontaneous
exergonic
-ex. cellular respiration
rxns with a positive delta G are ____(spont or not).
= _________ (ender/exergonic)
- example
non-spontaneous
endergonic
-ex. photosynthesis
energy from exergonic rxns are used to power endergonic rxns= ___ ______
energy coupling
-
C5
- charge repulsion
- steric hinderance
the 3rd phosphate in ATP has a ___ energy bond
high
everyone hates the 3rd phosphate!
Hydrolysis of ATP –> ADP + Pi can do 13kcal of work ie delta G=
the delta G is -13kcal/mol under ideal conditions
often the 3rd phosphate of ATP is transferred to a reactant. Why?
the addition of a phosphate makes the reactant more reactive/ spontaneous
ATP can be regenerated during _____ _____
cellular respiration
Cells couple ATP hydrolysis to power ___ rxns
endergonic
enzymes=
biological catalysts that provide an alternate energy path for a rxn to proceed with a lower activation energy
- fxn in both endergonic and exergonic rxns
- highly regulated in the cell
enzymes decrease the ___ ____ but do NOT change ____
activation energy
delta G
- enzymes bind and act on ____ (which they are very specific to)
- enzymes have an ____ ___ (binding site of substrate- catalysis)
- active/ catalytic site has ___ and ______ compatibility with substrate
- substrates
- active site
- geometric and chemical
catalysis=
reactants converted to products
- often proceeded by enzyme induced fit
Enzymes lower Ea for a rxn by:
List 5 different ways
- bringing reactants closer together
- active site contains a unique chemical enviro favorable for rxn
- physically stress bonds to be broken
- covalently stabilize rxn intermediate
- place substrates in correct orientation (panda example!)
Certain chemicals selectively inhibit the action of specific enzymes. What are the 2 types of enzyme inhibitors?
- Competitive inhibitors
2. non- competitive inhibitor
Competitive inhibitors=
- can be outcompeted by:
inhibitor that binds the active site but does not participate in a rxn
- increase [substrate]
Non-Competitive inhibitors=
inhibitor that binds a site on the enzyme that is not the active site and blocks enzyme activity
- changes shape of active site
