Introduction of Bioenergetics Part 1
Summary
TLDRThis video from Easy Peasy, presented by Seher, explains bioenergetics, focusing on energy transfer and utilization in biological systems. It covers key concepts like energy, ATP (adenosine triphosphate) as the body's energy currency, and Gibbs free energy. The video dives into spontaneous and non-spontaneous processes, thermodynamic systems, and their classifications. The distinction between endergonic and exergonic reactions is discussed through examples like photosynthesis and cellular respiration. The video also emphasizes how these energy transformations support life's processes, from growth to cellular function.
Takeaways
- 🌱 Bioenergetics refers to the transfer and utilization of energy in biological systems.
- ⚡ Energy is the capacity to perform work, necessary for everything from movement to basic biological processes.
- ☀️ The primary source of energy for life on Earth is sunlight, which plants convert into glucose via photosynthesis.
- 🍽️ Humans obtain glucose either by consuming plants directly or by eating animals that consume plants.
- 🔋 ATP (adenosine triphosphate) is the energy currency of the body, used to power all bodily functions.
- 💥 Gibbs free energy (ΔG) represents the energy available to do work and predicts whether a process is spontaneous or non-spontaneous.
- 🌡️ The equation ΔG = ΔH - TΔS shows how changes in enthalpy (ΔH), entropy (ΔS), and temperature (T) affect free energy.
- 🔥 Reactions can be exergonic (ΔG < 0, releasing energy) or endergonic (ΔG > 0, requiring energy).
- 🌳 Photosynthesis is an endergonic reaction, requiring energy from sunlight to produce glucose and oxygen.
- 🌀 Cellular respiration is the reverse of photosynthesis and is an exergonic process that releases energy in the form of ATP.
Q & A
What is the meaning of the term 'bioenergetics'?
-Bioenergetics refers to the study of energy transfer and utilization in biological systems.
How does energy differ in biological systems compared to machines?
-While machines like cars and mixers derive energy from gas and electricity, biological systems, including humans, obtain energy from food which is ultimately converted from sunlight through plants.
What is the role of ATP in the human body?
-ATP, or adenosine triphosphate, serves as the energy currency for the human body, providing the necessary energy for various bodily functions.
What is the Gibbs free energy, and how is it calculated?
-Gibbs free energy (delta G) is a thermodynamic potential that measures the maximum reversible work that may be done by a system at a constant temperature and pressure. It is calculated using the equation delta G = delta H - T * delta S, where delta H is the change in enthalpy, T is the temperature, and delta S is the change in entropy.
What is the significance of the terms 'enthalpy' and 'entropy' in the context of bioenergetics?
-Enthalpy represents the total energy of a system, while entropy is a measure of the randomness or disorder within that system. Both are crucial in understanding energy transformations in biological processes.
How does the concept of 'free energy' relate to spontaneous and non-spontaneous processes?
-Free energy, or Gibbs free energy, indicates the amount of energy available to do work. A negative delta G value signifies a spontaneous process that can occur without external energy input, while a positive delta G value indicates a non-spontaneous process that requires external energy.
What are the three types of systems in thermodynamics?
-The three types of systems in thermodynamics are open systems, where both mass and heat can transfer; closed systems, where mass cannot transfer but heat can; and isolated systems, where neither mass nor heat can transfer.
Why is the Gibbs free energy of photosynthesis positive?
-The Gibbs free energy of photosynthesis is positive because it is an endergonic reaction, meaning it requires energy input, in this case, from sunlight, to convert carbon dioxide and water into glucose and oxygen.
How does cellular respiration differ from photosynthesis in terms of energy transformation?
-Cellular respiration is the reverse of photosynthesis, involving the breakdown of glucose to produce carbon dioxide, water, and ATP. It is an exergonic reaction, releasing energy stored in glucose.
What is the activation energy, and how does it relate to the Gibbs free energy?
-Activation energy is the minimum energy required to start a chemical reaction. In the context of Gibbs free energy, it represents the energy barrier that must be overcome for a reaction to proceed. A negative Gibbs free energy indicates that the reaction releases energy, which can be used to overcome this barrier.
How does the conversion of ATP to ADP illustrate the concept of exergonic and endergonic reactions?
-The conversion of ATP to ADP and inorganic phosphate is an exergonic reaction, releasing energy. Conversely, the synthesis of ATP from ADP and inorganic phosphate is an endergonic reaction, requiring an input of energy.
Outlines
🌱 Introduction to Bioenergetics
The video introduces bioenergetics, explaining that 'bio' means life and 'energetics' refers to energy. Bioenergetics is the study of energy transfer and utilization in biological systems. Energy, defined as the capacity to do work, is essential for all life processes, from human growth to cellular functions like respiration, even during sleep. While machines like cars and mixers get energy from fuel and electricity, humans derive energy from food, which ultimately comes from the sun through plants. The energy stored in food is converted to ATP, the energy currency of the body, used for various activities.
⚡ ATP: The Energy Currency of Life
Adenosine triphosphate (ATP) is the energy source for all biological processes. It releases energy when the high-energy bonds between phosphate groups break, turning into ADP (adenosine diphosphate). The process releases free energy, also known as Gibbs free energy, which is the energy available to perform work. Gibbs free energy can predict whether a process is spontaneous or non-spontaneous. Spontaneous processes, like a person walking downhill, require less energy, while non-spontaneous processes, such as lifting weights, require external energy.
🧪 The Gibbs Free Energy Equation
The Gibbs free energy equation (ΔG = ΔH - TΔS) is introduced, where ΔG represents Gibbs free energy, ΔH is enthalpy (total energy), T is temperature, and ΔS is entropy (measure of disorder). Enthalpy refers to the total energy in a system, while entropy measures randomness or disorder. These terms are explained with analogies, like a car going downhill and hitting a tree with varying levels of heat and work. The amount of energy is independent of the pathway taken, making energy a 'state function.'
🌡 Types of Systems: Open, Closed, and Isolated
There are three types of systems: open, closed, and isolated. An open system allows both mass and heat to transfer, like a boiling pot without a lid. A closed system, with a lid, allows heat but not mass transfer. An isolated system allows neither mass nor heat transfer, with a thermos as an example. The isolated system holds the most energy, or enthalpy. Entropy, or disorder, increases as substances change state—from solid to liquid to gas.
🔄 Entropy, Enthalpy, and Gibbs Free Energy
The relationships between entropy, enthalpy, and Gibbs free energy are discussed. As the total energy (enthalpy) decreases, so does the Gibbs free energy. If temperature or entropy increases, the Gibbs free energy decreases. A positive ΔG value indicates a non-spontaneous (endergonic) reaction, requiring energy input. A negative ΔG value indicates a spontaneous (exergonic) reaction, releasing energy. These concepts are applied to photosynthesis, where energy is absorbed from sunlight, resulting in a positive ΔG and an endergonic reaction.
☀️ Photosynthesis: An Endergonic Process
Photosynthesis is explained using the Gibbs free energy model. Six molecules of carbon dioxide and water react to produce glucose and oxygen. During this process, entropy decreases as glucose, a more ordered molecule, is formed. Since the process absorbs energy from sunlight, the total enthalpy increases, leading to a positive ΔG value. This makes photosynthesis an endergonic reaction, which requires energy to produce glucose. The graph of this reaction shows that the reactants have less energy than the products, and the required activation energy is provided by sunlight.
🌬 Cellular Respiration: An Exergonic Reaction
Cellular respiration is the reverse of photosynthesis, with glucose being broken down into carbon dioxide and water, releasing energy in the form of ATP. In this reaction, entropy increases as the products are more disordered, and enthalpy decreases since energy is released. This results in a negative ΔG value, categorizing cellular respiration as an exergonic reaction. A graph of this process shows that the reactants have higher energy than the products, confirming that energy is released.
💡 ATP Cycle: Exergonic and Endergonic Reactions
The ATP cycle is discussed, where ATP breaks down into ADP and inorganic phosphate in an exergonic reaction, releasing energy. Conversely, when ADP is converted back into ATP, the process requires energy, making it an endergonic reaction. This constant transformation of energy within the ATP cycle enables humans to perform a wide variety of tasks, powering life's processes.
Mindmap
Keywords
💡Bioenergetics
💡Energy
💡ATP (Adenosine Triphosphate)
💡Gibbs Free Energy
💡Photosynthesis
💡Cellular Respiration
💡Enthalpy
💡Entropy
💡Exergonic Reaction
💡Endergonic Reaction
Highlights
Bioenergetics describes the transfer and utilization of energy in biological systems.
Energy is the capacity to do work, similar to how a car uses gas or a mixer uses electricity.
Humans need energy for basic functions like walking, growing, and even while sleeping.
The primary source of energy for life on Earth is sunlight, which plants convert into glucose via photosynthesis.
ATP (adenosine triphosphate) is the energy currency of the human body, with high-energy phosphate bonds.
When ATP bonds break, free energy is released, driving various biological processes.
Free energy, also known as Gibbs free energy, determines whether a process is spontaneous or non-spontaneous.
Gibbs free energy equation: ΔG = ΔH - TΔS, where ΔG is free energy, ΔH is enthalpy, T is temperature, and ΔS is entropy.
Spontaneous processes (negative ΔG) require no external energy, while non-spontaneous processes (positive ΔG) do.
Enthalpy refers to the total energy of a system, while entropy measures disorder or randomness in a system.
In open systems, both mass and heat can transfer, while closed systems only transfer heat, and isolated systems transfer neither.
Photosynthesis is an endergonic reaction with a positive ΔG, requiring energy input from sunlight.
Cellular respiration is the reverse of photosynthesis, an exergonic reaction with a negative ΔG, releasing energy.
ATP hydrolysis is an exergonic reaction that releases energy, while ATP synthesis requires energy and is an endergonic process.
The balance of endergonic and exergonic reactions in cells helps maintain energy flow and enables life processes.
Transcripts
[Music]
hello this is seher from easy peasy and
the topic we are going to discuss today
is called as bio energetics
if we look at the word bioenergetics
bio means life
and energetics come from the word energy
so the definition of bioenergetic is
that it will describe the transfer in
utilization of energy in biological
systems
now the question is what is energy
energy means the capacity for doing work
just like a car is going for miles on
gas
or a mixer is running on electricity so
they are getting energy from these
sources just like that humans need
energy to walk to grow from toddler into
an adult the process of fertilization
and fetal development also needs energy
and even when we are sleeping and not
doing any work
our lungs are working and our heart is
beating so we are still using energy so
just like other machines human beings
also need energy now for planet earth
the main source of energy is sunlight
and we are not asking our from seven
deadly sins who can absorb energy
directly from sunlight
rather the sunlight energy is absorbed
by plants with the help of carbon
dioxide and water it can convert this
light energy into glucose
and this glucose will be utilized by us
either by eating those plants directly
or by eating those animals that are
eating those plants
so directly or indirectly we are taking
this glucose and will convert it in the
form of atp with the byproducts of water
and carbon dioxide
this atp is the energy source for our
body to do every type of work
atp stands for adenosine
triphosphate
now this is the energy currency of human
body and the bonds that are connecting
these phosphate groups have high energy
in them
when these bonds get dissociate from
each other it will remove one inorganic
phosphate and release free energy now
the question is what is free energy
free energy is also called as gibbs free
energy and it can be defined as the
amount of energy available to do work it
can also predict whether the process
will be done or not
for example if a person is moving down a
hill it will need less amount of energy
this type of process is called a
spontaneous process
and if a person is lifting weight it
cannot do it without the help of
instructor
now it is taking energy from external
source
so this type of process is called as
non-spontaneous process the equation of
gibbs free energy is delta g is equal to
delta h minus t into delta s
in which delta g is gibbs free energy
delta h is the change in enthalpy
t is the temperature and delta s is the
change in entropy
now if you're a biologist you might get
confused with the terminology called as
enthalpy and entropy
so let's define them first and then we
will move forward in order to understand
these terms we need to go back into the
chemistry class
well in chemistry if we are taking a
conical flask in a box
that conical class will be a system
and the box will be called as the
surrounding
together system plus surrounding will
make universe in the system there are
two things that can be exchanged from
system to surrounding or from
surrounding to system the first thing is
the mass or the work and the second
thing is the heat
in order to understand it let's take an
example of a car running down the hill
now in the first case if this car is
moving slowly down the hill and hit this
tree then it will cause a fender bender
in this case the car is hitting brake
constantly so it will producing a lot of
heat energy there and then it will hit
the tree slightly that's why there is
less damage there so there will be a
less work
if this person is not hitting brake and
will hit the tree with full force in
that case the car will use less heat
but it will do more work by breaking
this tree or breaking the core
in both the situation the amount of
energy is
the same
so the amount of energy is independent
of the pathway it is taking
that's why it is also called as state
function
now systems can be of three different
types
one is called as open system
one is called as closed system and the
third one is isolated system
in an open system
both mass and heat can transfer from
system to its surrounding
for example a boiling pot of water in
this case the water is evaporating so
the mass is transferring plus the heat
is releasing from the pot
the other system is the closed one so if
we put a lid on top of this pot then the
mass will not transfer outside into the
surrounding but the heat can still
transfer from the system to its
surrounding
to this type of system is called as
closed system
the third type of system is called as
isolated system
in which neither mass nor heat can
transfer from system to its surrounding
for example a coffee thermos in which
the least amount of heat can be
transferred from system into the
surrounding
there is no real life example of an
isolated system
now in all these three systems the most
amount of energy is present in the
isolated system so the total amount of
energy present in the system is called
as enthalpy
so in all these three examples isolated
systems have the highest enthalpy
okay let's talk about entropy now
entropy is a mayor of randomness or
disorder in a system
so for example if we are taking ice
the molecules present within eyes are
intact they are vibrating but they are
not moving around
so the entropy of ice is low
now if this ice is converted into water
then these molecules will have more
space and will move more randomly
now if this water is going to convert
into vapors then the molecules present
in the gas state will have more area to
cover
so the entropy in the gas state is
higher as compared to liquid and solid
okay now we know what is enthalpy and
what is entropy let's compare them that
what will happen to the gibbs free
energy if one of the things will change
itself so if the total energy of a
system will change or going down
now it is equal to gibbs free energy the
grip's free energy will also be down
if the temperature of a system will be
high
now it is in the minus situation so if
this value is a bigger one then we will
have a negative g value so gibbs free
energy will go down
the same is the case with entropy so if
entropy is going up the gibbs free
energy will go down
in order to summarize it if the delta g
value is greater than zero or in the
positive state
then that type of process is endergonic
reaction it means that their
non-spontaneous reaction they will need
energy in order to produce their
products
and if the delta g value is less than
zero or a negative value then those type
of reactions are exergonic reactions it
means that it doesn't really need energy
in order to make products
okay
now let's understand this delta g value
in photosynthesis
in photosynthesis we need six molecules
of carbon dioxide and six molecules of
water when they will react with each
other they will produce sugar and six
molecules of oxygen so i'm going to show
this equation like this
so we have six molecules of carbon
dioxide with six molecules of water and
then we are producing glucose with six
molecules of oxygen
if we look at the screen right now we
can see that the entropy of the system
is lowering itself into glucose like it
is not that much random because glucose
is a bigger molecule and it is more
intact as compared to carbon dioxide and
water on the reactant side so in the
equation the entropy is less and the
total energy of the product is higher
because they are taking energy from
sunlight so the total enthalpy is
greater for the system
so
the gibbs free energy will be higher or
greater than zero
so the gibbs free energy of
photosynthesis is 686 kilocalories
and it is in the positive state so this
type of reaction is
endergonic reaction if we look this
reaction in a graph
we can see that the reactants have less
energy and the products have more energy
so the delta g will be higher than zero
now what is this slope here this slope
is basically the activation energy
required to perform this function and
this activation energy is provided by
sunlight here make sense
okay now let's talk about cellular
respiration now cellular respiration is
the opposite of photosynthesis so we
will just change the arrow from products
to reactants now this is cellular
respiration now if we look at the
entropy here we can see that it was more
intact in the reactant form and it is
more disordered in the product form so
the total entropy of the system is
higher if we look at the enthalpy of
this reaction we can see that glucose is
converted into carbon dioxide and water
and it is releasing energy in the form
of atp molecule so
the total enthalpy of the products are
lower here
that's why the delta g value of cellular
respiration is a negative value so this
type of reaction is exergonic reaction
now if we look at this reaction in the
form of a graph we can see that
reactants have higher energy as compared
to the products
and delta g value is less than zero here
so this type of reaction is exergonic
reaction
if we look this thing in atp molecule
the same thing applies here
now here adenosine triphosphate have
high energy here so when this atp will
convert into adp and inorganic phosphate
this type of process is called as
exergonic reaction but when this adp
will convert back into atp
this reaction will need energy there and
that type of process is called as
endergonic reaction by these reactions
and the transformation of energy from
one product to the other we can express
ourselves like this and make our life
beautiful
thank you very much for watching this
video if you like it please subscribe
our channel thank you bye
[Music]
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