The purpose of this page is to provide a brief survey of fundamental components of life.
Matter is any object that takes up space and has Mass. In gravitational fields, objects that have mass also have weight.
Examples of objects composed of matter:
Examples of phenomena not composed of matter:
Energy is any phenomenon that makes matter move.
Energy often is considered in the following forms:
Nuclear (pronounced: new -- klee --ar) – energy involving sub-atomic particles such as protons, neutrons, quarks and muons. Nuclear reactors slowly release nuclear energy to boil water. Atomic and hydrogen bombs rapidly release nuclear energy to produce explosive results. Stars are bright because of their continuous, rapid processing of fusion nuclear energy. The interiors of planets can be molten because of the continuous processing of fission nuclear energy.
Electromagnetic – radiating energy that travels as waves through space-time at the speed of light. Electromagnetic energy includes the following components of the electromagnetic spectrum: radio, radar, microwave, infrared, light, ultraviolet, x-rays, gamma rays and cosmic rays.
Chemical – energy based on the configurations of atoms in physical substances. Chemical energy is transferred when the physical configurations change. This can happen when atoms are added to or taken from a molecule. Chemical energy can be easily stored. Substances that store chemical energy include: sugar, fat, starch, cellulose, paper, wood, gasoline, coal, natural gas.
Electrical – energy made up of the flow of electrons through a conducting material, based on differences in electrical charge. Batteries have two connectors, each with an electrical charge opposite the other’s. Bridging these connectors causes electrons to flow from one to the other. Engineers capture this flow of electrons and use it to heat stove elements, light rooms, flip switches, fill up memory cards, and run computers.
Mechanical – energy in moving objects, often associated with mechanisms such as mechanical clocks, cars, bicycles, and aircraft. Human skeletons are mechanisms. When a foot strikes a soccer ball, mechanical energy is transferred from the foot to the ball.
Heat – energy associated with the motion of small particles like atoms and molecules. Heat energy causes small particles to move around quickly. For example, in reduced heat conditions, water molecules stop moving around and transform from a liquid substance into a solid substance (ice).
An atom is the smallest particle of an element that maintains the chemical properties of the element. An atom’s structure consists of a nucleus and an electron cloud, or shell. Protons and neutrons occupy the nucleus and electrons occupy the electron cloud. Under normal conditions, atoms can interact with each other. These atom-to-atom interactions are chemical interactions (as opposed to nuclear interactions).
The “Elements” is a term that refers to the names for all of the different kinds of atoms in nature. As of 2010, scientists have observed 118 unique kinds of atoms. Each kind of atom is given a name and is referred to by name. Differences in atoms is based on variations in the number of the atom’s protons, neutrons and electrons. For example, all atoms with a single proton and a single electron are chemically identical, and are called “hydrogen” atoms. Carbon atoms have six protons, six neutrons and six electrons and behave identically to each other, but differently from hydrogen atoms.
The biological world contains hundreds of thousands (if not millions) of unique molecular formulations. Biologists recognize that molecules, rather than being random lumps of matter, perform rewarding services for their biological unit. The nature of a molecule's activity is determined by the specific placement of different kinds of atoms, and the shape of the final construction.
Biological molecules are constructed out of many different kinds of atoms including: carbon, hydrogen, oxygen, nitrogen and sulfur atoms.
There are several main categories of biological molecules including:
DNA is a particularly interesting and powerful molecule because of its ability to hold discrete bits of data in an orderly manner.
The data bits of a DNA molecule are in the form of a small set of different "base" molecules. As the base molecules are unique, they act as discrete data bits like letters in an alphabet or numbers in a counting system. The base molecules form the cross-members of the double helix, holding the two strands together. By varying the sequence of base molecules in a section, its data arrangement changes.
Some data sequences provide useful code sequences for the fabrication of proteins (especially enzymes). In other words, the data sequence in DNA informs the cell about how to construct useful molecules. As a result, it is reasonable to consider DNA as an information storage medium. And because the bits of information storage are discrete, DNA's information storage system has the attributes of a digital information system.
Digital information systems include written language (using an alphabet of characters), numbering systems, digital computers, music CDs, and DVDs. Digital systems are superior to analog systems in that information can be copied endlessly with no loss in fidelity. This is why CDs sound so much better than vinyl LPs and cassette tapes.
This system of information management is extremely robust, given that the DNA you inherit from your parents must be copied trillions and trillions of times throughout your life.
A chemical reaction is a phenomenon when two or more chemical substances interact in such a way that one or more of the participants is chemically transformed as a result. Chemical transformation usually involves the loss or gain of atoms. For example, when molecular hydrogen (H2) reacts with molecular oxygen (O2), both are transformed and result in a completely new chemical substance, water (H2O).
H2 + O2 ----------> H2O
Note that chemical reactions involve simply the rearrangement of existing atoms. Atoms are neither created nor destroyed in chemical reactions.
Fixed carbon is carbon that has been converted from a gaseous form (like CO2) to a solid form (initially, short chains of carbon atoms). Photosynthesis is the main biochemical process on Earth that "fixes" carbon. Fixed carbon from photosynthesis is fed to many different biosynthetic pipelines that assemble much larger molecules like sugars, proteins, fats, nucleic acids and specialty molecules like vitamins.
The organic body of any living thing is composed of fixed carbon.
Photosynthesis is a biochemical process (system of many different chemical reactions) that consumes CO2, H2O and light energy to build short chains of carbon (fixed carbon). Water is used as a source of hydrogen atoms to stabilize the chains, and resultant oxygen atoms are released as waste O2.
The carbon chains then can be passed to other biochemical synthetic pipelines inside the cell for the assembly of carbohydrates, proteins, fats, nucleic acids and other kinds of biological molecules. Apart from other functional properties, all molecules of fixed carbon store sizeable amounts of chemical energy.
The general chemical expression for photosynthesis is:
Cellular respiration disassembles molecules of fixed carbon, releasing the chemical energy stored in them. The disassembly process produces large amounts of unescorted hydrogen atoms that, if allowed to accumulate, could clog up the system. Molecular oxygen (O2 ) is brought in to clear out these hydrogen atoms by combining with them to make water (H2O). The disassembled carbon is released as CO2.
The general expression for cellular respiration is:
Living things grow by the addition of cells much in the same way that a wall grows by the addition of bricks. So, in order to support the growth and maintenance of new cells, living things constantly consume resources from their surrounding environment.
And as the cells in living things do their work, they are constantly producing wastes that are released to the surrounding environment.
In the simplest terms, a gene is a section of a DNA molecule that codes for a particular trait. We can think of a gene as the fundamental unit of information related to a given trait.
Specifically, genes hold information for the construction of protein molecules inside the cell. Enzymes are special kinds of protein molecules that are the "action" molecules. By varying the types and quantities of enzymes in the cell, the overall cell operation can be controlled.
Depending upon the genes available, there will be qualitative and quantitative differences in cell operations, trait operations and functioning of the whole organism.
Individual living things do not synthesize their own genes. Rather, they inherit them from parent, or parents. The inherited genes are then copied over-and-over as the individual adds new cells in its development. Generally, each living cell of an individual contains identical copies of the original genes inherited from parents. As a result, individuals are genetically constrained by the genetic makeup of their parents. Individuals have no choice in the matter.
Genes are packaged together in large molecular structures called chromosomes. Chromosomes make for more efficient physical management of genes, especially during cell division. And chromosomes often engage in gene-swapping during sex cell (eggs and sperm) formation.
Alleles are genes that code for the same trait but in different ways. For example, let's consider the trait for "eye color" in a population of rabbits. In this population, there are four different genes for eye color red, green, blue, brown). That is, there are four different alleles for eye color. Alleles are alternative forms of a gene for a given trait. The more alleles for a given trait, the greater variety in the population.
Genetics is a science interested in the dynamics of genetic information in living things. Genetic information plays a variety of interesting roles in biology, particularly in reproduction, and the development, operation and maintenance of traits.
In the field of genomics, geneticists map out the location of genes on different chromosomes that influence a given trait. Recently, geneticists have mapped the entire collection of genes for many species, including humans.
Knowledge of genetics has helped physicians to understand the cause of genetic disorders.
Population genetics is the branch of genetics that tracks the frequencies of alleles from generation-to-generation in a population. Population geneticists identify the ebbs and flows of allele frequencies. Combined with the science of ecology, population genetics can help biologists identify environmental causes for a population's genetic changes. This effort is the basis for modern evolution theory.
Different Kinds of Living Things
Photosynthetic organisms usually require simple resources from their surroundings. These resources come in material form, such as carbon dioxide, molecular oxygen, nitrate salts (and other mineral salts) and water. Additional resources come in the form of energy, mainly sunlight.
Photosynthetic types also release materials back into their surroundings. Released chemicals include, carbon dioxide, molecular oxygen, water, nitrogen oxides and dimethyl sulfide.
Animals require a mix of simple and complex materials from their surroundings. Simple materials include molecular oxygen, water and mineral salts. More complex materials includes the bodies, products or remains of other living things -- otherwise referred to as food.
Animals return simple materials to their surroundings such as carbon dioxide, water and nitrogen salts. They also return complex materials including digestive wastes and their own bodies after death.
Decomposers consume and process the remains and wastes of all living things. Decomposition converts biological molecules into their basic components. For example, decomposers would convert a dead leaf into: carbon dioxide, nitrate salts, magnesium salts, sulfur salts, phosphorous salts and water. The results of decomposition are released into the surrounding environment.
As decomposers break down the complex mass of remains of once-living things (and their wastes), they return the most basic buidling blocks of life (collectively referred to as "mineral nutrients") to the environment.
Nitrogen fixing types
Copyright© 2009 by Tom E. Morris. All rights reserved.
Fullerton College is part of the
North Orange County Community College District