BLG 143 EXAM 3 QUESTIONS AND
CORRECT ANSWERS!!
What is the relationship between exergonic reactions, endergonic reactions and the use and
regulation of ATP?
- an exergonic reaction is energetically favourable. it will occur spontaneously and doesn't
require additional energy to react
- an endergonic reaction requires the addition of energy and as such it will not occur
spontaneously
- in nature, cells use ATP as an energy transporter. Energy is stored in ATP with the addition of
PO3 group to ADP and energy is released when ATP is hydrolyzed to ADP. This energy is used
to drive unfavourable reactions.
what characteristic of this molecule (ATP) is responsible for its high energy level
compound to AMP
the closely spaced negative charges associated with the phosphate group
an endergonic reaction may be energetically unfavourable. for example, dehydration
synthesis reactions to build polymers reduce entropy and are not thermodynamically
favourable. how does coupling of an exergonic reaction permit an overall reaction that is
energetically favourable?
- an exergonic reaction has a positive charge in Gibbs Free Energy.
- An exergonic reaction has a negative change in Gibbs free energy
- if the two reactions coupled, the net change in Gibbs free energy may be either positive or
negative. If the sum of two reactions results in a Gibbs free energy that is negative, then the pair
of reactions, collectively, will be energetically unfavourable.
explain how cellular respiration produced atp from molecules with high potential energy
such as glucose
in cells, glucose is oxidized through a long series of controlled steps, its energy is then harnessed
to fuel the synthesis of atp
, the four components of cellular respiration
Glycolysis: one molecule of glucose is broken down into two molecules of pyruvate, two atp are
produced and NAD+ is reduced to NADH
Pyruvate Processing: pyruvate is processed to form acetyl CoA during which another NADH is
produced
Citric Acid Cycle: acetyl CoA is oxidized to two CO2 molecules. During this cycle, more atp
and NADH is produced
Electron Transport & Chemiosmosis: electrons from NADH and FADH2 move through a series
of proteins called the electron transport chain. the potential energy released during these
reactions is used to create a proton gradient, which is used to make atp
the energy-investment phase of glycolysis refers to _______
the coupling of ATP hydrolysis with endergonic reactions in the early steps of the process
the energy payoff phase of glycolysis refers to _________
the net gain of ATP
substrate-level phosphorylation requires _______ and ______
phosphate group donor, an enzyme
after glycolysis and the citric acid cycle are complete, where is most of the energy that was
once contained in the bonds of glucose
in NADH and FADH2 that are carrying energy-rich electrons
in the krebs cycle, oxidation reactions are coupled with the reduction of NAD+ to NADH or
FADH+ to FADH2. whats the function of NADH and FADH2? what's their role in the
generation of ATP?
they donate electrons to the acceptors in the electron transport chain. these electrons then flow
through protein pumps, so the flow of the electrons is used to pump protons to the inside of the
CORRECT ANSWERS!!
What is the relationship between exergonic reactions, endergonic reactions and the use and
regulation of ATP?
- an exergonic reaction is energetically favourable. it will occur spontaneously and doesn't
require additional energy to react
- an endergonic reaction requires the addition of energy and as such it will not occur
spontaneously
- in nature, cells use ATP as an energy transporter. Energy is stored in ATP with the addition of
PO3 group to ADP and energy is released when ATP is hydrolyzed to ADP. This energy is used
to drive unfavourable reactions.
what characteristic of this molecule (ATP) is responsible for its high energy level
compound to AMP
the closely spaced negative charges associated with the phosphate group
an endergonic reaction may be energetically unfavourable. for example, dehydration
synthesis reactions to build polymers reduce entropy and are not thermodynamically
favourable. how does coupling of an exergonic reaction permit an overall reaction that is
energetically favourable?
- an exergonic reaction has a positive charge in Gibbs Free Energy.
- An exergonic reaction has a negative change in Gibbs free energy
- if the two reactions coupled, the net change in Gibbs free energy may be either positive or
negative. If the sum of two reactions results in a Gibbs free energy that is negative, then the pair
of reactions, collectively, will be energetically unfavourable.
explain how cellular respiration produced atp from molecules with high potential energy
such as glucose
in cells, glucose is oxidized through a long series of controlled steps, its energy is then harnessed
to fuel the synthesis of atp
, the four components of cellular respiration
Glycolysis: one molecule of glucose is broken down into two molecules of pyruvate, two atp are
produced and NAD+ is reduced to NADH
Pyruvate Processing: pyruvate is processed to form acetyl CoA during which another NADH is
produced
Citric Acid Cycle: acetyl CoA is oxidized to two CO2 molecules. During this cycle, more atp
and NADH is produced
Electron Transport & Chemiosmosis: electrons from NADH and FADH2 move through a series
of proteins called the electron transport chain. the potential energy released during these
reactions is used to create a proton gradient, which is used to make atp
the energy-investment phase of glycolysis refers to _______
the coupling of ATP hydrolysis with endergonic reactions in the early steps of the process
the energy payoff phase of glycolysis refers to _________
the net gain of ATP
substrate-level phosphorylation requires _______ and ______
phosphate group donor, an enzyme
after glycolysis and the citric acid cycle are complete, where is most of the energy that was
once contained in the bonds of glucose
in NADH and FADH2 that are carrying energy-rich electrons
in the krebs cycle, oxidation reactions are coupled with the reduction of NAD+ to NADH or
FADH+ to FADH2. whats the function of NADH and FADH2? what's their role in the
generation of ATP?
they donate electrons to the acceptors in the electron transport chain. these electrons then flow
through protein pumps, so the flow of the electrons is used to pump protons to the inside of the
