BMSC 230 FINAL COMPREHENSIVE GUIDE
2026 QUESTIONS WITH SOLUTIONS
GRADED A+
>> Metabolism
Answer: Enzyme catalyzed reactions that occur in all cells to either
breakdown biomolecules to obtain energy (ATP), or reactions that
synthesize biomolecules that our body needs
>> Metabolism is the sum of
Answer: Catabolism + Anabolism
>> Catabolism
Answer: Chemical reactions that breakdown biomolecules to produce
energy
>> Anabolism
• require energy input
Answer: Chemical reactions that lead to the synthesis of biomolecules
>> 4 primary functions of metabolism
• from energy rich nutrients, or solar energy
2. Convert ingested molecules into the building blocks of larger molecules
needed in the body
3. Assemble small building blocks into large building molecules
• protein, nucleic acids, lipids, polysaccharides
4. Synthesize and degrade biomolecules that have specialized functions in cells
Answer: 1. Obtain chemical energy in the form of ATP
,>> Metabolic pathway
A biomolecule converts into another biomolecule in a carefully defined fashion
• regulated conversion
Answer: A series of linked reactions
>> 3 types of metabolic pathways
• substrate —> product —> product —> final product
Branched - starts off linear and an intermediate leads to different branched
pathways
Circular - the starting biomolecule is the finish biomolecule
• citric acid cycle
Answer: Linear - straight line
>> Metabolic pathways are interconnected
• the intermediates connect the pathways
The integrated pathways can still be regulated independently by elegant and
sensitive mechanisms
Answer: An intermediate of one pathway can be the intermediate of another
pathway
>> Reactions in a pathway can be
Irreversible - only one direction
Answer: Reversible - both directions
>> The first step in a reaction pathway is
• prevents further steps
Typically the rate limiting step
Answer: Often the regulated step
>> Pathways that function both catabolically and anabolically are
• citric acid cycle
Answer: Amphibolic pathways
,>> Living organisms require a continual input of energy for 3 major purposes
• muscle contraction
• cellular movement
2. Active transport of biomolecules & ions
3. Synthesis of macromolecules from simple precursors
Free energy is captured from the environment
Answer: 1. The performance of mechanical work
>> Phototrophs
• plants
Answer: Use photosynthesis to convert energy from the sunlight into
chemical form
>> Chemotrophs
• humans
Answer: Obtain energy in the form of ATP through the oxidation of carbon
fuels such as fats and carbohydrates
>> Enzymes only
• canNOT make a thermodynamically unfavourable reaction proceed
Answer: Speed up the rate of a chemical reaction, they do NOT change the
equilibrium constant for reactions
>> Two thermodynamic properties
• deltaG determines spontaneity
The free energy required to initiate the conversion of reactants to products
• the rate at which the reaction will proceed
• enzyme affects rate
Answer: The free energy difference (deltaG) between the products and
reactants
>> Spontaneous reactions occur when
• exergonic - release energy
, Answer: deltaG is negative
>> Non-spontaneous reactions
• often involving ATP cleavage - endergonic
Answer: Have a positive deltaG and require the input of energy
>> When a system is at equilibrium
• deltaG = 0
Answer: There is no net change in the concentration of reactants and
products
>> deltaG provides No info on
• only spontaneity
Answer: The rate of the reaction
>> deltaG of the forward reaction
deltaG• = standard free energy change
• at standard conditions (1.0M, 1atm, 298K, pH7)
R = gas constant
T = absolute temp (K)
Answer: deltaG = deltaG• + RT ln ([prod]\[react])
>> A simple way to calculate the concentration of the reactants and products
when the reaction has reached equilibrium and deltaG is 0
deltaG•' = -2.3RT log Keq
Keq = ([prod]/[react])
Answer: deltaG•' = -RT Keq —>
>> Relationship between Keq & deltaG
• equilibrium
Keq < 1 —> deltaG•' = +
• favours the reverse reaction
Keq > 1 —> deltaG•' = -
2026 QUESTIONS WITH SOLUTIONS
GRADED A+
>> Metabolism
Answer: Enzyme catalyzed reactions that occur in all cells to either
breakdown biomolecules to obtain energy (ATP), or reactions that
synthesize biomolecules that our body needs
>> Metabolism is the sum of
Answer: Catabolism + Anabolism
>> Catabolism
Answer: Chemical reactions that breakdown biomolecules to produce
energy
>> Anabolism
• require energy input
Answer: Chemical reactions that lead to the synthesis of biomolecules
>> 4 primary functions of metabolism
• from energy rich nutrients, or solar energy
2. Convert ingested molecules into the building blocks of larger molecules
needed in the body
3. Assemble small building blocks into large building molecules
• protein, nucleic acids, lipids, polysaccharides
4. Synthesize and degrade biomolecules that have specialized functions in cells
Answer: 1. Obtain chemical energy in the form of ATP
,>> Metabolic pathway
A biomolecule converts into another biomolecule in a carefully defined fashion
• regulated conversion
Answer: A series of linked reactions
>> 3 types of metabolic pathways
• substrate —> product —> product —> final product
Branched - starts off linear and an intermediate leads to different branched
pathways
Circular - the starting biomolecule is the finish biomolecule
• citric acid cycle
Answer: Linear - straight line
>> Metabolic pathways are interconnected
• the intermediates connect the pathways
The integrated pathways can still be regulated independently by elegant and
sensitive mechanisms
Answer: An intermediate of one pathway can be the intermediate of another
pathway
>> Reactions in a pathway can be
Irreversible - only one direction
Answer: Reversible - both directions
>> The first step in a reaction pathway is
• prevents further steps
Typically the rate limiting step
Answer: Often the regulated step
>> Pathways that function both catabolically and anabolically are
• citric acid cycle
Answer: Amphibolic pathways
,>> Living organisms require a continual input of energy for 3 major purposes
• muscle contraction
• cellular movement
2. Active transport of biomolecules & ions
3. Synthesis of macromolecules from simple precursors
Free energy is captured from the environment
Answer: 1. The performance of mechanical work
>> Phototrophs
• plants
Answer: Use photosynthesis to convert energy from the sunlight into
chemical form
>> Chemotrophs
• humans
Answer: Obtain energy in the form of ATP through the oxidation of carbon
fuels such as fats and carbohydrates
>> Enzymes only
• canNOT make a thermodynamically unfavourable reaction proceed
Answer: Speed up the rate of a chemical reaction, they do NOT change the
equilibrium constant for reactions
>> Two thermodynamic properties
• deltaG determines spontaneity
The free energy required to initiate the conversion of reactants to products
• the rate at which the reaction will proceed
• enzyme affects rate
Answer: The free energy difference (deltaG) between the products and
reactants
>> Spontaneous reactions occur when
• exergonic - release energy
, Answer: deltaG is negative
>> Non-spontaneous reactions
• often involving ATP cleavage - endergonic
Answer: Have a positive deltaG and require the input of energy
>> When a system is at equilibrium
• deltaG = 0
Answer: There is no net change in the concentration of reactants and
products
>> deltaG provides No info on
• only spontaneity
Answer: The rate of the reaction
>> deltaG of the forward reaction
deltaG• = standard free energy change
• at standard conditions (1.0M, 1atm, 298K, pH7)
R = gas constant
T = absolute temp (K)
Answer: deltaG = deltaG• + RT ln ([prod]\[react])
>> A simple way to calculate the concentration of the reactants and products
when the reaction has reached equilibrium and deltaG is 0
deltaG•' = -2.3RT log Keq
Keq = ([prod]/[react])
Answer: deltaG•' = -RT Keq —>
>> Relationship between Keq & deltaG
• equilibrium
Keq < 1 —> deltaG•' = +
• favours the reverse reaction
Keq > 1 —> deltaG•' = -
