Why Are You Alive – Life, Energy & ATP

At this moment you are on a narrow border between

life

and death. You probably don't feel it, but there is an incredible amount of activity within you, and this activity can never stop. Imagine yourself as a Slinky falling down an ascending escalator. The fall part represents the self-replication processes of your cells. The escalator represents the laws of physics that propel you forward. To be

alive

is to be in motion, but never getting anywhere. When you reach the top of the escalator, you will no longer be able to fall and you will be dead forever. Somewhat ominously, the universe wants you to come out on top.

How do you avoid it? And why do you live? All

life

is based on the cell. A cell is a piece of the dead universe that separated itself from the rest so it could do its own thing for a while. If this separation is broken, he dies and reunites with the rest of the dead universe. Unfortunately, the universe wants life to be done its way. For some reason, she doesn't like exciting things, but instead tries to be as boring as possible. We call this principle "entropy" and it is a fundamental rule of our universe. It's quite complicated and counterintuitive, so we'll explain it in detail in another video.

For now, all you need to know is that living things are inherently exciting. A cell is filled with millions of proteins and millions of simpler molecules, like water. Thousands of complex, self-replicating processes occur hundreds of thousands of times per second. To stay

alive

and exciting, you must constantly work to avoid reaching entropy and becoming boring and dead. The cell must maintain a separation from the rest of the universe. This is achieved, for example, by maintaining the concentration of certain molecules inside and pumping out excess active molecules outside. To do things like this, a cell needs

energy

.

Energy is the ability of things in the universe to do work; move or manipulate a thing; to create changes. This ability cannot be created or destroyed. The fixed amount of

energy

in the universe will never change. We don't know why, it's just that way. Therefore, millions of years ago, the most important life for the first living beings was to obtain usable energy. We don't know much about the first cells, except that they got their energy from simple chemical reactions. And they found the definitive energy transfer system: the energy component of life. The molecule adenosine triphosphate or ATP.

Its structure makes it unique when it comes to accepting and releasing energy. When a cell needs energy, for example to pump molecules or repair a broken micromachine, it can break down ATP and use the chemical energy to do work and effect changes. That is why living beings can do things. We do not know when or how the first ATP molecule was formed on Earth. But all living things we know use ATP, or something similar, to keep the internal machinery running. It is very important for almost all processes. Plants, fungi, bacteria and animals must survive. Without ATP there is no life on Earth.

Possibly anywhere. Although breaking down chemicals for energy is fun, the first few years of life they missed out on the largest source of energy available: the sun. The Sun fuses atoms and emits photons that carry energy throughout the solar system. But this energy is raw and indigestible. It needs to be refined. After hundreds of millions of years of evolution, a cell finally figured out how to eat the sun. It absorbed radiation and converted much of it into small chemical packets that it could use to stay alive. We call this process: Photosynthesis. Photons wrapped in electromagnetic energy are taken and some of this energy is used to bind and combine different molecules.

Electromagnetic energy is converted into chemical energy that is stored in the ATP molecule. This process improved further as some cells learned to create better chemical packages: glucose or sugar. Easy to break down, lots of energy and lots of fun. It's so convenient that some cells have decided that instead of doing all the tedious photosynthesis themselves, they'll simply gobble up other cells that have already done it and absorb their glucose and ATP. This is widely considered one of the biggest anime betrayals in evolutionary history. And so things continued. Photosynthesizing cells can primarily use energy on their surfaces, which limited their maximum energy production, which somewhat limited their evolutionary paths.

That's how time passed. Some cells made sugar, others ate it. Evolution has done its thing, but overall things have remained largely the same for hundreds of millions of years. Until one day the cell ate another and did not kill it. Instead, they became a single cell. Nothing changed that day, but the earth would forever be different. This cell became the ancestor of all animals on this planet. Blue whales, amoeba. Dinosaurs, jellyfish. Pink Fairy Armadillos and Sunda Colugos. And of course, you. Everyone can trace their existence to this moment. The fusion of two living beings is so important because when the two cells became one, they became much more powerful.

The previously independent cell inside might stop trying to survive. You can focus on one thing: making ATP. It became the nerve center of the cell: the first mitochondria. The host's task is to ensure survival in a dangerous world and provide food for the mitochondria. Mitochondria are basically reverse photosynthesis, in an equally complex process. They take sugar molecules that we get from eating other living things, burn them with oxygen and precursor molecules to produce new energy-rich ATP molecules. This process works like a small oven, spitting out waste products like CO2, water, and some kinetic energy that is experienced as body heat.

This first division of labor meant that the new cell had much more energy available than any previous cell, meaning more possibilities for evolution to make more complicated cells possible. At some point, these cells began to form small groups or communities, giving rise to multicellular life and, eventually, you. Today, you are a bunch of trillions of cells, each filled with dozens, if not hundreds, of tiny machines that provide you with usable energy to keep you alive. If this process is interrupted, you will die even for a few minutes. (Preview of Kurzgesagt: Science War, available in 2021.) But if life is so fragile, it wouldn't be a good idea to store ATP, just like we store sugar in our fat cells, so we don't die if we don't stop breathing for a while. time?

If life has solved so many problems to allow you to live today, what happens to the dying thing? Even simple bacteria like E. Coli produce about 50 times their body weight in ATP per cell division. Your trillions of cells need a lot of ATP to keep going. Your body produces and converts about 90 million, billion, billion ATP molecules every day – about your own body weight. You need the ATP of an entire person just to get through a single day. In reality, it is impossible to even store enough ATP for a few minutes. An ATP molecule is very good at moving energy quickly, but it is terrible at storing it because it has only one percent of the energy of a glucose molecule three times its mass.

Therefore, ATP is constantly produced and consumed quite quickly. That was the short and simplified story of the molecule that allows you to be different from the dead universe, and to be the sneaky one on the escalators. It's a strange story. There is this molecule that you must survive at all times. You need to keep it moving because even a brief pause stops your sneak. And you have to do it yourself. It's like driving a car at full speed while producing fuel in the trunk with garbage collected on the side of the road. As far as we know, it began billions of years ago, when small parts of the dead universe came together and became something more for a moment.

You can move on. Can grow up. At that point the slinky started up and has been running ever since. From the first cells to what you are seeing now. At some point you will merge back into the rest of the dead universe. Maybe you tell him stories about your adventures. Maybe not. But before you know it, you must do what life does best. Making a dead universe much more interesting. (With a Supreme Slinky poster in your room.) *Quack* Duck: Why am I floating aimlessly in this universe?