The Chemistry of Life

For educational purposes

Energy is defined as the capacity to do work or to put matter into motion, and of course the greater amount of work done, the greater amount of energy is used doing the work. Compared with matter, energy is much less tangible, having no mass. It does not take up any space. We can measure it only by the effects that it causes on matter. 

What is matter?

Matter is the stuff of the universe, or better yet, matter is anything that occupies space and has mass with some exceptions. Matter can be seen and smelled, as well as felt. The state of matter exists in of course solids, liquids, and gas. 

Energy exists within two states and each can be transformed to the other.

So, what are they?

We have kinetic energy, which is energy in action, or the work getting done by moving objects which in turn can do additional work by moving or pushing on other objects.

We have potential energy, which is stored energy that is inactive with the potential or capability to do the work, but is not presently doing the work.

Unused batteries have potential energy. The same can be said for water behind a dam.

When potential energy is released, it becomes kinetic energy, which is capable to do the work. For example, water in a dam becomes rushing water when the dam is opened to move a turbine.

But there are also forms of energy, so what are those?

Chemical energy

This is the form of energy stored in the bonds of chemical substances, and when the chemical reactions occur, there is a rearrangement of the atoms of those chemicals in a way that can store potential energy.

When those bonds are broken, the energy released becomes kinetic, or energy inaction that can go do work.

An example of this is some of the energy within the foods that you eat is eventually converted into kinetic energy, so you can go do work.

Electrical energy

This is the energy that results from the movement of charged particles. A perfect example of this is within your home, in the electrical energy that is found in the flow of electrons along the household-wiring. In your body, however, electrical currents are generated when charged particles called ions move along or across your cellular membranes.

The nervous system uses electrical currents called nerve impulses for the transmission of signals from one neuron to another, sending signals throughout body.
Electrical currents travel across your heart stimulating it to contract and pump the blood. This is why a strong electrical shock will interfere with that signal and can come to cause death.

Mechanical energy

This energy is directly involved in moving matter. When you are riding a bike, your legs provide the mechanical energy that come to move the pedals.

Radiant energy, or electromagnetic radiation

This is energy that travels within waves. These waves, which do vary in length, collectively are called the electromagnetic spectrum. This is including visible light, infrared waves, radio waves, ultraviolet waves, and x-rays.

Ultraviolet waves cause sunburn, but also stimulates your body to make vitamin D. Energy is generally easily converted from one form to another, but energy conversions are also very inefficient. Some of the initial energy supply is lost to the environment as heat.

This energy is not really lost.

Why, you ask?

Well, because energy can not be created nor destroyed, but that portion of energy that is given off as heat is unusable and all the energy conversions within the body create heat.

This heat helps to maintain our body temperature, which is influencing bodily function.

For example, when matter is heated, the kinetic energy of its particles increases, meaning the particles of the matter begin to move quicker. So, the higher the temperature, the faster the chemical reactions have the ability to occur 

Matter is composed of the elements, which are substances that cannot be broken down into simpler substances by ordinary chemical methods. You have heard of some of them.

The well-known elements are oxygen, carbon, gold, silver, copper, and iron. 

You might not believe this, but the 4 elements carbon, oxygen, hydrogen, and nitrogen make up about 96% of body weight, and 20 others can be found in small amounts.

So, what is an element?

They are substances that cannot be broken down into simpler substances, but each element is made up of particles or building-blocks called atoms. 

The word 'atom' comes from the Greek word, with the meaning 'indivisible;' however, we know that the atom is made up of even smaller particles. These are the following:

• Protons which have a positive electrical charge
• Neutrons which having a neutral charge
• The nucleus or center of the atom, which contains protons and neutrons tightly bound together
• The tiny electrons have a negative charge equal in strength to the positive charge of a proton; however, the electron has only about 1/2000 the mass of a proton and the electrons orbit the center nucleus of the atom.

All atoms are electrically neutral because the number of protons in a atom are balanced by its number of electrons orbiting the nucleus, meaning the positive and negative charges will then cancel the effect of each other out.

For example, hydrogen has one proton and one orbiting electron for the atom. The number of protons and electrons are equal. All protons are alike regardless of the atom in consideration. The same is true for all the neutrons as well as for all the electrons.

So, what is determining unique properties of each element?

Atoms of different elements are made up of different numbers of the protons, different numbers of neutrons, and different numbers of the electrons.

The simplest of all the smallest atoms, hydrogen, has one proton, one electron, and no neutron.

The next in line is helium, which has two protons, two neutrons, and two orbiting electrons. 

Lithium follows with 3 protons, 4 neutrons, and 3 electrons.

In truth, all we really know about any particular element is the atomic number, mass number, and atomic weight.

The atomic number of any atom is equal to the number of protons within the nucleus. The mass number of atom is the sum of the protons and neutrons Atomic weight is the average of the weights of the mass numbers of all the isotopes of an element. Isotopes of an element are the same element but differing in weight.

Most atoms are not existing in what is called a free state; instead they are chemically combined with other atoms. 

Resources

Anatomy & Physiology Textbook 6th Edition