HMX biochemistry practice exam 2022| 163
questions| with complete solutions
energy needed to get a reaction started Correct Answer: activation energy
respresented in a reaction coordinate diagram. Positive is thermodynamically unfavorable.
Negative is thermodynamically favorable (exergonic - release energy). = G(products) -
G(reactants) Correct Answer: Delta G (change in G - change in free energy)
catalyze chemical reaction. Lower activation energy. Biological catalyst (protein) Correct
Answer: enzyme
results in decrease in activity of that enzyme, reaising activation enregy of reaction it catalyzes
Correct Answer: enzyme inhibition
results in increase in activity of that enzyme, lowering activation energy of reaction it catalyzes
Correct Answer: enzyme activation
when rate of forward and reverse reactions are same. Concentration of products and reactants
don't change appreciably over time but reaction is going. On average, same # of A + B reactions
and C splitting reactions occurring a given period of time Correct Answer: equilibrium
property of a molecule that reflects its capacity to do work. Determined by potential energy
stored in chemical bonds and concentration/physical parameters (temperature) Correct Answer:
Gibbs' Free Energy (G)
central pathway in breakdown of carbs for energy. Series of 10 reactions. 1 glucose --> 2
pyruvate. - change in G of whole pathway but some reactions have positive change in G. Net
formation of 2 ATP and 2 NADH for each glucose Correct Answer: glycolysis
one molecule is transformed into another molecule which has exactly the same atoms, but atoms
have a different arrangement. ABC --> BAC. Chemical formula doesn't change but atoms are
rearranged. Correct Answer: isomerization
enzymes that catalyze reactions in which a molecule is phosphorylated. Ex. Hexokinase
catalyzes the phosphorylation of glucose. Phosphofructokinase 1 (PFK-1) catalyzes
phosphorylation of phosphofructose (Fructose 6-phosphate) Correct Answer: Kinase
when a system is initially at equilibrium, then perturbed away from equilibrium, it will
counteract the perturbation to move back towards equilibrium (change in G not equal to 0), either
forward or reverse reaction is more thermodynamically favorable. Low activation energy Correct
Answer: Le Chatelier's principle
results of some process serve to counteract that process. maintains a variable in a narrow range at
homeostasis. Correct Answer: negative feedback
, sum total of all chemical changes that occur if molecules are consumed in one reaction but
produced in another in equal quantity, they aren't included Correct Answer: net reaction
enzymes that remove phosphates from molecules Correct Answer: phosphatase
substance formed as a result of chemical reaction. Right Correct Answer: products
starting materials for a reaction. Undergo a chemical change. Left Correct Answer: reactants
tells whether reaction is thermodynamically favorable or unfavorable Correct Answer: reaction
coordinate diagram
adenosine & 2 phosphate groups Correct Answer: adenosine diphosphate (ADP)
energy currency of life, high energy molecule that stores energy we need to do anything.
Universal unit of energy exhange Correct Answer: adenosine triphosphate (ATP)
simple sugar which is an important energy source in living organisms. Component of many
carbs. Reactant of glycolysis. Correct Answer: glucose
coenzyme in all living cells. Required for fundamental biological processes. Oxidized form
Correct Answer: NAD+, nicotinamide adenine dinucleotide
reduced form. Shuttle for electrons during cellular respiration. universal unit of energy exchange
Correct Answer: NADH
2 formed by glycolysis. Inhibit/Regulate PFK-1 Correct Answer: Pyruvate
phosphate group is remoed from molecule. Type of hydrolysis reaction. Often bypass reactions
for phosphorylation reactions Correct Answer: Dephosphorylation
molecules split by reacting with water Correct Answer: Hydrolysis
phosphate group is transferred from one molecule (often ATP or another nucleotide triphosphate)
to another. Reactions that use ATP for energy. Chemical addition of phosphoryl group (PO3-) to
an organic molecule Correct Answer: phosphorylation
activity of enzymes in biological pathways can be dialed up and down, depending on
requirements of cell Correct Answer: Regulation
point in biochemical pathway where same molecule can be converted into many other molecules,
depending on what enzymes are present and avtive in a cell Correct Answer: branch point
questions| with complete solutions
energy needed to get a reaction started Correct Answer: activation energy
respresented in a reaction coordinate diagram. Positive is thermodynamically unfavorable.
Negative is thermodynamically favorable (exergonic - release energy). = G(products) -
G(reactants) Correct Answer: Delta G (change in G - change in free energy)
catalyze chemical reaction. Lower activation energy. Biological catalyst (protein) Correct
Answer: enzyme
results in decrease in activity of that enzyme, reaising activation enregy of reaction it catalyzes
Correct Answer: enzyme inhibition
results in increase in activity of that enzyme, lowering activation energy of reaction it catalyzes
Correct Answer: enzyme activation
when rate of forward and reverse reactions are same. Concentration of products and reactants
don't change appreciably over time but reaction is going. On average, same # of A + B reactions
and C splitting reactions occurring a given period of time Correct Answer: equilibrium
property of a molecule that reflects its capacity to do work. Determined by potential energy
stored in chemical bonds and concentration/physical parameters (temperature) Correct Answer:
Gibbs' Free Energy (G)
central pathway in breakdown of carbs for energy. Series of 10 reactions. 1 glucose --> 2
pyruvate. - change in G of whole pathway but some reactions have positive change in G. Net
formation of 2 ATP and 2 NADH for each glucose Correct Answer: glycolysis
one molecule is transformed into another molecule which has exactly the same atoms, but atoms
have a different arrangement. ABC --> BAC. Chemical formula doesn't change but atoms are
rearranged. Correct Answer: isomerization
enzymes that catalyze reactions in which a molecule is phosphorylated. Ex. Hexokinase
catalyzes the phosphorylation of glucose. Phosphofructokinase 1 (PFK-1) catalyzes
phosphorylation of phosphofructose (Fructose 6-phosphate) Correct Answer: Kinase
when a system is initially at equilibrium, then perturbed away from equilibrium, it will
counteract the perturbation to move back towards equilibrium (change in G not equal to 0), either
forward or reverse reaction is more thermodynamically favorable. Low activation energy Correct
Answer: Le Chatelier's principle
results of some process serve to counteract that process. maintains a variable in a narrow range at
homeostasis. Correct Answer: negative feedback
, sum total of all chemical changes that occur if molecules are consumed in one reaction but
produced in another in equal quantity, they aren't included Correct Answer: net reaction
enzymes that remove phosphates from molecules Correct Answer: phosphatase
substance formed as a result of chemical reaction. Right Correct Answer: products
starting materials for a reaction. Undergo a chemical change. Left Correct Answer: reactants
tells whether reaction is thermodynamically favorable or unfavorable Correct Answer: reaction
coordinate diagram
adenosine & 2 phosphate groups Correct Answer: adenosine diphosphate (ADP)
energy currency of life, high energy molecule that stores energy we need to do anything.
Universal unit of energy exhange Correct Answer: adenosine triphosphate (ATP)
simple sugar which is an important energy source in living organisms. Component of many
carbs. Reactant of glycolysis. Correct Answer: glucose
coenzyme in all living cells. Required for fundamental biological processes. Oxidized form
Correct Answer: NAD+, nicotinamide adenine dinucleotide
reduced form. Shuttle for electrons during cellular respiration. universal unit of energy exchange
Correct Answer: NADH
2 formed by glycolysis. Inhibit/Regulate PFK-1 Correct Answer: Pyruvate
phosphate group is remoed from molecule. Type of hydrolysis reaction. Often bypass reactions
for phosphorylation reactions Correct Answer: Dephosphorylation
molecules split by reacting with water Correct Answer: Hydrolysis
phosphate group is transferred from one molecule (often ATP or another nucleotide triphosphate)
to another. Reactions that use ATP for energy. Chemical addition of phosphoryl group (PO3-) to
an organic molecule Correct Answer: phosphorylation
activity of enzymes in biological pathways can be dialed up and down, depending on
requirements of cell Correct Answer: Regulation
point in biochemical pathway where same molecule can be converted into many other molecules,
depending on what enzymes are present and avtive in a cell Correct Answer: branch point
