1- How does the movement of electrons between outer and inner shells illustrate the
conversion between potential and kinetic energy, and what implications does this have for
cellular processes that rely on electron transport?
Electrons in outer shells have more potential energy because they are farther from the
nucleus. When an electron moves to an inner shell, it loses potential energy and releases it
as kinetic energy, usually as light or heat. This idea is similar to what happens in cellular
processes like cellular respiration and photosynthesis, where electrons move between
molecules in an electron transport chain. Each movement releases energy step by step,
and cells capture that energy to make ATP. This shows how living systems convert stored
energy into usable energy to perform work, like muscle contraction, and maintain cell
structure.
2- Explain how the Gibbs free energy equation (ΔG = ΔH - TΔS) predicts whether a chemical
reaction is spontaneous. What factors influence whether a reaction is endergonic or
exergonic?
The Gibbs free energy equation combines three factors: enthalpy (ΔH), entropy (ΔS), and
temperature (T). It shows whether a reaction will happen on its own. When ΔG is negative,
the reaction is spontaneous (exergonic) and releases energy. When ΔG is positive, the
reaction is non-spontaneous (endergonic) and needs energy to occur. A reaction’s direction
depends on whether heat is released or absorbed and how much disorder (entropy)
increases. For example, cellular respiration has a negative ΔG because it releases energy,
while photosynthesis has a positive ΔG because it requires energy input.
3- In biological systems, how does entropy (disorder) influence the direction of chemical
reactions, and how do cells overcome the natural tendency toward increased disorder to
maintain structure and function?
According to the second law of thermodynamics, all systems move toward greater entropy,
or disorder. This means that without energy input, molecules naturally break down and
become less organized. However, living cells fight this disorder by constantly using energy
from ATP to build and repair structures. For example, cells use anabolic reactions to make
complex molecules like proteins from smaller pieces. This keeps the system ordered but
requires continuous energy input. Without this energy use, the cell’s structures would
break down, and life could not continue.