, Energy and metabolism-
Every living cell uses energy to preform a wide variety of functions such as-
Anabolic reactions - energy is required to from large large molecules such as DNA replication
Catabolic reaction- release energy by breaking down complex molecules into their components. An example of major catabolism
pathway is cellular respiration
Energy-
Energy cannot disappear or be created from nothing.
Energy can be transferred between organisms or environment through
exchange path.
There are several types of energy-
Kinetic energy- relative movement of objects
Thermal energy-kinetic energy associated with the random movement
of atoms or molecules ; heat movement describes the transfer of thermal
energy from one object to another.
Potential energy- chemical energy - potential energy available for
release a chemical reaction
Light energy- can be used to preform work, such as photosynthesis in
plants.
Universe= the system + the surrounding
Thermodynamics-is the study of different energy forms in a system.
There are two laws of thermodynamics relate to energy transformation in organisms and their
Organisms are said to be an
surroundings-
“open system” meaning they
The first law of thermodynamics-
can preform energy
Energy can be transferred but it cannot be created or destroyed.
transformations between
During energy transfer( transformation)some energy becomes unavailable to preform more work
themselves and their
- Loss of heat which dissipates quickly into the surroundings.
surroundings i.e the universe.
The second law of thermodynamics-
Entropy (S) is a quantity measure of molecular disorder of randomness . The more disordered a
group of matter the greater it’s entropy. Every energy/transfer or transformation increases the
entropy of the universe.The total entropy(S) of an isolated system can only increase or remain
constant.
Favorable and unfavorable reactions -
Spontaneous(catabolism)reactions- occur without requiring an
input of energy > lead to increase in entropy
Reaction are energetically favorable when-
They result in a decrease in their own content of energy (e.g
heat) and an Increase in the entropy of the system
Spontaneous dose not mean that a
Non-spontaneous reactions/Unfavorable process(anabolic)
Process occurs quickly. Some Leads to a decrease in entropy and Usually require the input
spontaneous process are very slow energy.
Free-energy change ( G)
In 1878 Willard Gibs defined a formula called the Gibbs free energy of a system.
Free energy is the potential or the availability of a system’s energy to preform . When a system changes e.g a cell during a
chemical reaction,the free energy changes as well.
G= H - T S
G=Change in free energy S= change in the
Only processes with negative G ( G<0) are
system entropy
spontaneous
H= change in the systems
enthalpy T-absolute temperature
Enthalpy in biological systems is
equivalent to heat energy
By calculating the free energy value of a process,we can predict whether the process will be spontaneous (energetically favorable).Thus
we can know whether the process requires an input of energy.
Every living cell uses energy to preform a wide variety of functions such as-
Anabolic reactions - energy is required to from large large molecules such as DNA replication
Catabolic reaction- release energy by breaking down complex molecules into their components. An example of major catabolism
pathway is cellular respiration
Energy-
Energy cannot disappear or be created from nothing.
Energy can be transferred between organisms or environment through
exchange path.
There are several types of energy-
Kinetic energy- relative movement of objects
Thermal energy-kinetic energy associated with the random movement
of atoms or molecules ; heat movement describes the transfer of thermal
energy from one object to another.
Potential energy- chemical energy - potential energy available for
release a chemical reaction
Light energy- can be used to preform work, such as photosynthesis in
plants.
Universe= the system + the surrounding
Thermodynamics-is the study of different energy forms in a system.
There are two laws of thermodynamics relate to energy transformation in organisms and their
Organisms are said to be an
surroundings-
“open system” meaning they
The first law of thermodynamics-
can preform energy
Energy can be transferred but it cannot be created or destroyed.
transformations between
During energy transfer( transformation)some energy becomes unavailable to preform more work
themselves and their
- Loss of heat which dissipates quickly into the surroundings.
surroundings i.e the universe.
The second law of thermodynamics-
Entropy (S) is a quantity measure of molecular disorder of randomness . The more disordered a
group of matter the greater it’s entropy. Every energy/transfer or transformation increases the
entropy of the universe.The total entropy(S) of an isolated system can only increase or remain
constant.
Favorable and unfavorable reactions -
Spontaneous(catabolism)reactions- occur without requiring an
input of energy > lead to increase in entropy
Reaction are energetically favorable when-
They result in a decrease in their own content of energy (e.g
heat) and an Increase in the entropy of the system
Spontaneous dose not mean that a
Non-spontaneous reactions/Unfavorable process(anabolic)
Process occurs quickly. Some Leads to a decrease in entropy and Usually require the input
spontaneous process are very slow energy.
Free-energy change ( G)
In 1878 Willard Gibs defined a formula called the Gibbs free energy of a system.
Free energy is the potential or the availability of a system’s energy to preform . When a system changes e.g a cell during a
chemical reaction,the free energy changes as well.
G= H - T S
G=Change in free energy S= change in the
Only processes with negative G ( G<0) are
system entropy
spontaneous
H= change in the systems
enthalpy T-absolute temperature
Enthalpy in biological systems is
equivalent to heat energy
By calculating the free energy value of a process,we can predict whether the process will be spontaneous (energetically favorable).Thus
we can know whether the process requires an input of energy.
