Cellular Life

Proteins and Energy

Table of Contents

Energy Causes Movement

Adenosine Tri-Phosphate

Cellular Respiration

The Release of Energy

Aerobic Respiration - 32 ATP

Energy, from the Sun to your Proteins

Summary and Questions

Energy Causes Movement

Without energy nothing moves.

Energy caused the formation of our planet.

Energy causes earthquakes. Energy causes Volcanoes and their gases to erupt, spewing Carbon Dioxide into the air.

Energy causes air to move. Energy causes carbon dioxide to move into leaves.

Energy causes the water cycle.

Energy causes carbon dioxide to combine with water to make glucose.

Energy causes you to move and to eat food. You eat food for energy (and atoms).

Energy causes your heart to beat.

Energy causes glucose to be turned back into carbon dioxide and water. Energy causes cells to be 'alive'.

Energy causes Proteins to Move.

Proteins need Energy to move.

Proteins moving is life.

Each protein that is made in your body needs energy to be made as it is made by Ribosomes.

Ribosomes are proteins that move.

Ribosomes are enzymes.

Enzymes are proteins that do stuff.

Doing stuff requires energy

You can only do stuff if you have energy.

Each protein needs energy to do each of the movements it must make to do the stuff that it does.

So to type, how many proteins are doing stuff and how many movements does it take to do that stuff and how does energy get to where it needs to for these movements to occur?

If we trace the source of energy for us and for all large life on earth, we find that the energy comes from the sun and is put into the systems of life through photosynthesis.

We saw that photosynthesis is powered by energy from the Sun.

We know that this energy moves through food chains.

But how does that energy get to your Proteins?

When compounds with lots of atoms are made from compounds that have few atoms, a lot of energy has to be put in. Some of that energy stays in the big compound.

In other words, it takes lots of energy to build complex compounds from simple compounds and some of that energy is stored in the complex compound as chemical potential energy.

When a big compound with lots of atoms is broken down into smaller compounds with fewer atoms, energy needs to be put in to start the reaction, but lots of energy is then released from the big compound

In other words, it takes some energy to start to deconstruct complex molecules into simple molecules, but that deconstruction releases lots of stored chemical potential energy

This is much like building a brick wall, and then pushing it over.

Building by hand takes lots of energy. Pushing it over takes some energy. When it crashes down and brakes back into bricks we hear that energy being released.

Photosynthesis makes the complex compound glucose from the simple compounds carbon dioxide and water.

To make glucose, energy from light is put in. Some of the energy put in is 'lost' as heat. Some remains within the compounds.

So glucose contains more chemical potential energy than water and carbon dioxide.

When we break that complex glucose back down to Carbon dioxide and water, the stored energy within the molecule is 'released'.

But how does this 'released' energy get to the millions of proteins working in each cell?

What if I told you, that you have millions of Tiny Batteries inside your cells.

What if I told you that it is these tiny batteries that take energy to proteins.

Solar energy, from the sun, is stored in glucose as Chemical Potential Energy.

This glucose is broken apart in your cells and turned back into carbon dioxide and water

As it is broken apart energy is released

This energy is used to recharge the batteries that power the thousands of protein actions occurring in a cell every second

Billions of protein actions within your body every second of every day

These batteries have two names, one when flat and one when recharged:

When fully charged they are Adenosine Triphosphate, ATP
When flat they are Adenosine Diphosphate, ADP

Adenosine Tri-Phosphate

The above two clips are here to show what ATP does inside a cell

ATP contains Adenine - the same as the Adenine or the A of ATCG found in DNA. Attached to the Adenine is a Ribose sugar, the same as the ribose from RNA.

Together: Adenine + Ribose = Adenosine

This Adenine + Ribose then has a phosphate attached to it. The same as the phosphate backbone of RNA.

This links back to the chemical evolution of life, with the same molecules doing different functions to continue the uninterrupted string of reactions that have been running for billions of years to maintain life on our planet

Adenosine Diphosphate contains 2 of these phosphate groups

Adenosine Diphosphate is a stable molecule.

Adenosine Diphosphate is the flat battery.

When glucose is broken, some of that energy escapes as heat - this keeps us warm

When glucose is broken, some of that energy is used to attach a third phosphate group to ADP.

This makes the molecule Adenosine Triphosphate, or ATP

This phosphate is only loosely held on and breaking it off requires very little activation energy, but it releases a large amount of energy

This energy, released right up against proteins, cause them to change shape (usually by the temporary attachment of the third phosphate to the protein.

After the protein changes shape, the phosphate might be released, causing the protein to change its shape back.

Cellular Respiration

The Release of Energy

We really do 'burn our food.

The chemical equation is the same

The only difference is that we are over 60% water

For fire, the energy is released as heat and light

For respiration, the energy is used to charge the ADP batteries, turning them into ATP

Some is also lost as heat and Infrared light

Plants use energy from the sun to make glucose

They then make more complex molecules by linking glucose together or by reconstructing the carbon atoms into other molecules such as lipids

A vegetable oil can have over 100 atoms. Sunflower oil has 55 Carbons, 98 Hydrogens and 6 Oxygens.

To make this molecule, the plant has to put in a lot of energy. This large complex molecule thus contains a lot more energy than glucose.

The muscle cells of a human will burn these fat molecules preferentially. It takes time for the cell to break down and burn fat, but it will get a lot of energy from it.

However, much like burning paper or burning a log, it is easier and faster to burn glucose.

The human body will convert big fat molecules into lots of smaller glucose molecules in the liver.

These smaller glucose molecules can be burnt in all cells, from muscle cells to brain cells.

This Burning inside of water filled cells is called Respiration

To burn the fuel, to burn glucose, the cells need oxygen

To have a good strong fire, you need oxygen

To burn the fuel, to burn glucose, the cells need oxygen

This graph compares the energy released from burning glucose in a fire and burning glucose through cellular respiration

Glucose in both cases has the same amount of energy to start with

The end products; Carbon Dioxide and water, both have far less energy than glucose

Notice that in the fire a large amount of activation energy is required to start the reaction of combining oxygen to the glucose to start making carbon dioxide and water. This is the heat required to burn sugar

Notice that in respiration there is lots of small activation energies - this is because the reaction is catalyzed by enzymes

All of the energy from glucose is released very quickly in the fire

The energy from glucose is slowly released in cellular respiration, allowing the energy to be 'captured' and used to put phosphates onto ADP to make ATP

Aerobic Respiration - 32 ATP

To attach a phosphate onto Adenosine Diphosphate to make Adenosine Triphosphate energy is required

During Cellular respiration, energy is slowly released from glucose.

This energy is used to attach Phosphates onto Adenosine Diphosphates

This process is step by step

At the end of it you will have attached 38 Phosphates onto 38 Adenosine Diphosphates to make 38 Adenosine Triphosphates

38 ATP

This process of creating 38 ATP from 38 ADP uses:

1 Glucose + 6 Oxygen molecules = 6 Carbon dioxide + 6 Water

It is the reverse of photosynthesis

The fact that these two systems are linked, make the chemical reactions of photosynthesis and cellular respiration sustainable. They can run in unison for billions of years.

Fueling living systems with solar Energy. Taking energy from the sun and releasing it within living cells

You make 38 ATP, but to power the enzymes involved in the process of aerobic respiration you use up 6 of them. So 6 ATP are turned back into ADP to overcome the activation energy of several of the steps.

So its a profit of only 32 ATP

Though some places say that the profit is 36 and others say that the profit is 34, current research indicates that the profit is 32 ATP

This process is called Aerobic Respiration because Oxygen is used.

Aerobic = Air

Aerobic Respiration:

1 Glucose + 6 Oxygen molecules = 6 Carbon dioxide + 6 Water