Introduction of Bioenergetics Part 1

Summary

This 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

00:00

🌱 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.

05:02

⚡ 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.

10:03

🧪 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.

Keywords

💡Bioenergetics

Bioenergetics refers to the study of the transfer and utilization of energy in biological systems. In the video, it is introduced as the core theme, explaining how living organisms manage energy for various functions, such as movement and growth. The video highlights the importance of bioenergetics in processes like cellular respiration and photosynthesis.

💡Energy

Energy is defined as the capacity to do work. The video uses analogies, such as a car running on gas and a mixer operating on electricity, to explain how energy powers human activities and biological functions. Even when we are resting, our body still uses energy to perform essential tasks like breathing and maintaining a heartbeat.

💡ATP (Adenosine Triphosphate)

ATP, or Adenosine Triphosphate, is described as the 'energy currency' of the human body. It stores energy in the bonds between phosphate groups, and when these bonds break, energy is released to power biological processes. The video emphasizes that ATP is vital for various functions, from muscle contractions to cell division.

💡Gibbs Free Energy

Gibbs free energy refers to the amount of energy available to do work in a system. It is crucial in determining whether a biological process, like a chemical reaction, will occur spontaneously. The video explains that spontaneous reactions (negative Gibbs free energy) release energy, while non-spontaneous reactions (positive Gibbs free energy) require external energy input.

💡Photosynthesis

Photosynthesis is the process by which plants convert sunlight into glucose, using water and carbon dioxide. The video describes it as an endergonic reaction, where energy from sunlight is absorbed to create glucose and oxygen. This glucose is essential for human energy, either through direct consumption of plants or through animals that eat plants.

💡Cellular Respiration

Cellular respiration is the opposite of photosynthesis and is described as an exergonic reaction. In this process, glucose is broken down into carbon dioxide and water, releasing energy in the form of ATP. The video contrasts it with photosynthesis by highlighting how it releases stored energy, while photosynthesis stores energy from sunlight.

💡Enthalpy

Enthalpy is defined as the total energy present in a system. In the video, it is associated with state functions, meaning the total energy remains constant regardless of the pathway taken. It is used to explain the energy changes in open, closed, and isolated systems, with examples like boiling water and coffee thermoses.

💡Entropy

Entropy measures the disorder or randomness in a system. The video uses the example of ice, water, and vapor to illustrate how entropy increases from a solid state to a gas state. It is a key concept in understanding how Gibbs free energy decreases as entropy increases in biological systems.

💡Exergonic Reaction

Exergonic reactions are those that release energy, and they have a negative Gibbs free energy value. The video uses cellular respiration as an example of an exergonic process, where energy is released as glucose is broken down into carbon dioxide and water, driving various biological functions.

💡Endergonic Reaction

Endergonic reactions require an input of energy, as their Gibbs free energy value is positive. The video highlights photosynthesis as an example of an endergonic process, where plants absorb sunlight to produce glucose, a more energy-rich molecule. This contrasts with exergonic reactions, which release energy.

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]