BCH 3120 Midterm 1 Test Study
Guide A+ Graded
what is metabolism? - ANSWER sum of biochemical processes involved in the synthesis
(anabolism), breakdown (catabolism) and inter-conversion of constituents in cells and
organisms
energy containing nutrients vs energy depleted end products - ANSWER catabolism
breaks down carbs, fat and proteins (energy-containing nutrients) into CO2, H2O and
NH3 (end products)
*which releases energy to make ATP
precursor molecules vs cell macromolecules - ANSWER anabolism builds proteins,
polysaccharides, lipids and nucleic acids (macromolecules) from amino acids, sugars,
fatty acids and nitrogenous bases (precursors)
*using energy from ATP
what is a metabolic pathway? - ANSWER series of enzymatic reactions leading to a
product (metabolites)
eg. carbohydrate, lipid, amino acid, nucleic acid metabolism
what are the main characteristics of metabolic pathways? (5) - ANSWER - irreversible
path (cannot back track)
- anabolism and catabolism use different pathways (depending on energy demand,
independent control, may have some similar reactions)
- each pathway has a committed step (irreversible reaction)
- all pathways are regulated
- take place is specific intracellular sites (cellular compartments, organs, tissues)
what are building blocks, workers and traffic control? - ANSWER nutrients/food,
enzymes/cofactors and compartmentalization/thermodynamics/enzymatic control help
keep systems in a steady state
5 control measures for resource usage - ANSWER - thermodynamics
- cell-cell communication and compartmentalization
- inhibition and allosteric control
,- post-translational modifications
- enzyme turnover
energy is provided by __ - ANSWER electron flow
electrons flow __ hill from __ to __ electrochemical potential - ANSWER down, higher,
lower
what is bond energy?
how does it differ between strong and weak bonds? - ANSWER energy required to break
a bond (energy is released when a bond is formed)
strong bonds are stable and have high bond energies
weak bonds have low bond energies
compare BOND energies of C-H vs C=O - ANSWER C-H has lower bond energy (start
with carbs with weak bonds)
C=O has high bond energy (end with strong bonds)
*note: C-H has higher POTENTIAL energy
high potential energy bonds are __ bonds because after the energy is input to break
them, the atoms are available to form ___ - ANSWER weak, newer/stronger/lower
potential energy bonds
*high energy = weak/unstable
what is enthalpy? - ANSWER the number and kinds of bonds involved in the reaction
delta H = bonds broken (reactants) - bonds formed (products)
energy in favourable vs unfavourable reactions - ANSWER favourable: reactants have
higher energy than products (energy is released as heat or light)
unfavourable: reactants have lower energy than products (uses energy)
*note: high energy = unstable -> want to make stable
what is entropy? - ANSWER the change in randomness of a reaction or system (delta S)
*note: want large to make delta G negative
what is Gibbs free energy? - ANSWER the measure of total free energy capable of doing
work for a reaction at a constant temperature and pressure
delta G = delta H - T delta S
if delta G is negative, free energy is __, the process is __
,if delta G is zero, free energy is __, the process is __
if delta G is positive, free energy is __, the process is __ - ANSWER available to do work,
thermodynamically favourable
zero, reversible (system is at equilibrium)
required to do work, thermodynamically unfavourable
what is energy coupling? - ANSWER a thermodynamically unfavourable (endergonic)
reaction will proceed if it is coupled to favourable (exergonic) reaction if it releases
more energy than the unfavourable reaction consumes -> combined delta G is negative
standard vs actual free energy change - ANSWER standard: delta G' is a CONSTANT
tells us direction of reaction for specific concentrations/conditions
acutal: varies because delta G depends on actual concentrations of reactants/products,
temperature and pressure (EXPERIMENTAL)
how does ATP link energy releasing reactions with energy demanding reactions? -
ANSWER catabolic reactions release energy = ADP -> ATP
anabolic reactions require energy = ATP -> ADP
*note: hydrolysis of ATP to ADP has ~-30 delta G'
ATP hydrolysis must be ___ in order for the energy to be __ (and not ____) - ANSWER
coupled to another reaction, used, released as heat
coupling involves the transfer of ___ from __ to ___ or __ = " ___ " - ANSWER phosphate
groups, ATP, enzyme or its substrate, group transfer reaction
ATP has a high ____ - ANSWER phosphoryl group transfer potential
rate limiting vs committing step - ANSWER rate limiting: slowest step determines rate of
entire path
committing: locks the metabolite in a particular path
*note: they may be the same step eg. glycolysis step 3 (most regulated?)
segregation - ANSWER controls metabolic pathways by removing a metabolite or
enzyme from other pathway (1 of 3 reasons for localization of distinct pathways)
eg. one step in mitochondria vs others in cytoplasm
, selective transport - ANSWER allows membrane receptors or proteins to control certain
steps by letting in or pumping out metabolites (1 of 3 reasons for localization of distinct
pathways)
eg. mitochondria membrane
metabolite sensing - ANSWER control of metabolic pathways by enzymes of receptors
or osmotic gradients sensing abundance of nutrients, metabolites and substrates (1 of 3
reasons for localization of distinct pathways)
eg. sense cholesterol in body -> signal to make more
localization of fatty acid oxidation vs fatty acid biosynthesis - ANSWER mitochondria vs
cytosol
want different compartments because use reaction in different directions
endogenous vs exogenous inhibitors - ANSWER end-products vs poisons
allosteric inhibition/activation - ANSWER binding at one site affects binding of another ->
structural alterations can interfere with accessibility or disturb catalytic site =
non-competitive
eg. isoleucine end-product allosterically inhibits enzyme 1 of threonine dehydratase for
its own synthesis
the __ pathway is an important component for the control of enzyme turnover
the __ motif is a tag
proteins with a N-term tag __ while those lacking __ - ANSWER ubiquitin pathway
PEST (proline, glutamic acid, serine, threonine sequence)
survive for 2-3 min, have a half-life of ~10 hours
carbohydrates consist of __ and __ - ANSWER one or more carbonyl groups, one or more
hydroxyl groups
Guide A+ Graded
what is metabolism? - ANSWER sum of biochemical processes involved in the synthesis
(anabolism), breakdown (catabolism) and inter-conversion of constituents in cells and
organisms
energy containing nutrients vs energy depleted end products - ANSWER catabolism
breaks down carbs, fat and proteins (energy-containing nutrients) into CO2, H2O and
NH3 (end products)
*which releases energy to make ATP
precursor molecules vs cell macromolecules - ANSWER anabolism builds proteins,
polysaccharides, lipids and nucleic acids (macromolecules) from amino acids, sugars,
fatty acids and nitrogenous bases (precursors)
*using energy from ATP
what is a metabolic pathway? - ANSWER series of enzymatic reactions leading to a
product (metabolites)
eg. carbohydrate, lipid, amino acid, nucleic acid metabolism
what are the main characteristics of metabolic pathways? (5) - ANSWER - irreversible
path (cannot back track)
- anabolism and catabolism use different pathways (depending on energy demand,
independent control, may have some similar reactions)
- each pathway has a committed step (irreversible reaction)
- all pathways are regulated
- take place is specific intracellular sites (cellular compartments, organs, tissues)
what are building blocks, workers and traffic control? - ANSWER nutrients/food,
enzymes/cofactors and compartmentalization/thermodynamics/enzymatic control help
keep systems in a steady state
5 control measures for resource usage - ANSWER - thermodynamics
- cell-cell communication and compartmentalization
- inhibition and allosteric control
,- post-translational modifications
- enzyme turnover
energy is provided by __ - ANSWER electron flow
electrons flow __ hill from __ to __ electrochemical potential - ANSWER down, higher,
lower
what is bond energy?
how does it differ between strong and weak bonds? - ANSWER energy required to break
a bond (energy is released when a bond is formed)
strong bonds are stable and have high bond energies
weak bonds have low bond energies
compare BOND energies of C-H vs C=O - ANSWER C-H has lower bond energy (start
with carbs with weak bonds)
C=O has high bond energy (end with strong bonds)
*note: C-H has higher POTENTIAL energy
high potential energy bonds are __ bonds because after the energy is input to break
them, the atoms are available to form ___ - ANSWER weak, newer/stronger/lower
potential energy bonds
*high energy = weak/unstable
what is enthalpy? - ANSWER the number and kinds of bonds involved in the reaction
delta H = bonds broken (reactants) - bonds formed (products)
energy in favourable vs unfavourable reactions - ANSWER favourable: reactants have
higher energy than products (energy is released as heat or light)
unfavourable: reactants have lower energy than products (uses energy)
*note: high energy = unstable -> want to make stable
what is entropy? - ANSWER the change in randomness of a reaction or system (delta S)
*note: want large to make delta G negative
what is Gibbs free energy? - ANSWER the measure of total free energy capable of doing
work for a reaction at a constant temperature and pressure
delta G = delta H - T delta S
if delta G is negative, free energy is __, the process is __
,if delta G is zero, free energy is __, the process is __
if delta G is positive, free energy is __, the process is __ - ANSWER available to do work,
thermodynamically favourable
zero, reversible (system is at equilibrium)
required to do work, thermodynamically unfavourable
what is energy coupling? - ANSWER a thermodynamically unfavourable (endergonic)
reaction will proceed if it is coupled to favourable (exergonic) reaction if it releases
more energy than the unfavourable reaction consumes -> combined delta G is negative
standard vs actual free energy change - ANSWER standard: delta G' is a CONSTANT
tells us direction of reaction for specific concentrations/conditions
acutal: varies because delta G depends on actual concentrations of reactants/products,
temperature and pressure (EXPERIMENTAL)
how does ATP link energy releasing reactions with energy demanding reactions? -
ANSWER catabolic reactions release energy = ADP -> ATP
anabolic reactions require energy = ATP -> ADP
*note: hydrolysis of ATP to ADP has ~-30 delta G'
ATP hydrolysis must be ___ in order for the energy to be __ (and not ____) - ANSWER
coupled to another reaction, used, released as heat
coupling involves the transfer of ___ from __ to ___ or __ = " ___ " - ANSWER phosphate
groups, ATP, enzyme or its substrate, group transfer reaction
ATP has a high ____ - ANSWER phosphoryl group transfer potential
rate limiting vs committing step - ANSWER rate limiting: slowest step determines rate of
entire path
committing: locks the metabolite in a particular path
*note: they may be the same step eg. glycolysis step 3 (most regulated?)
segregation - ANSWER controls metabolic pathways by removing a metabolite or
enzyme from other pathway (1 of 3 reasons for localization of distinct pathways)
eg. one step in mitochondria vs others in cytoplasm
, selective transport - ANSWER allows membrane receptors or proteins to control certain
steps by letting in or pumping out metabolites (1 of 3 reasons for localization of distinct
pathways)
eg. mitochondria membrane
metabolite sensing - ANSWER control of metabolic pathways by enzymes of receptors
or osmotic gradients sensing abundance of nutrients, metabolites and substrates (1 of 3
reasons for localization of distinct pathways)
eg. sense cholesterol in body -> signal to make more
localization of fatty acid oxidation vs fatty acid biosynthesis - ANSWER mitochondria vs
cytosol
want different compartments because use reaction in different directions
endogenous vs exogenous inhibitors - ANSWER end-products vs poisons
allosteric inhibition/activation - ANSWER binding at one site affects binding of another ->
structural alterations can interfere with accessibility or disturb catalytic site =
non-competitive
eg. isoleucine end-product allosterically inhibits enzyme 1 of threonine dehydratase for
its own synthesis
the __ pathway is an important component for the control of enzyme turnover
the __ motif is a tag
proteins with a N-term tag __ while those lacking __ - ANSWER ubiquitin pathway
PEST (proline, glutamic acid, serine, threonine sequence)
survive for 2-3 min, have a half-life of ~10 hours
carbohydrates consist of __ and __ - ANSWER one or more carbonyl groups, one or more
hydroxyl groups
