What Are Cilia

The term cilia is Latin for "eyelashes." Common in single-cell organisms, these hair-like structure wave to move the cell around or to move something around the cell. Cilia also are present on most cells in the human body. Some tissues in the body, such as the Fallopian tubes in women and the trachea, also have a special type of cilia that help transport substances along the tissues' surfaces.

Types of Cilia in the Body

In the body, cilia on the surface of tissues are responsible for protecting a person from germs in the lungs and for pushing an ovum through the Fallopian tube, among other tasks. These cilia are called motile cilia, and they are found in groups and beat in waves. Primary cilia, on the other hand, usually are found only one at a time on cells.

Structure

The structure of a single cilium is much like a tube, and its long fibers are called microtubules. These microtubules often pair up to form doublets, which in turn form a ring. The cross-section of doublets of microtubules looks like a figure 8, because the two microtubules stick together along a line. Nine doublets form the larger ring in what is known as a 9-2 pattern. When kinesin binds to one side of the doublets and not the other, the cilium flexes and curves, similar to the way a person's skeletal muscles contract. 

Functions

Single-celled eukaryotes, which are organisms with cells that have a nucleus, often use cilia to move through liquid. This type of organism is surrounded by a cytoskeleton, made of protein filaments that allow the cell to hold its shape. A cilium attaches to the cytoskeleton of the cell with a basal body, the way a root attaches hair to human skin. 

The rhythm of waving cilia is controlled by centrioles, which are organelles located inside the cell wall. Mitochondria, other units inside the cell, provide adenosine triphosphate (ATP), a source of cellular energy, for the cilia. The ATP directs the chemical kinesin to bind to certain parts of the cilia that control their movement. Thus, the cilia are able to beat or essentially swim their way through viscous liquid.

Flagella

Similar to cilia, flagella are longer such hairs, usually found in ones or twos, such as the tail of a sperm. They share many characteristics with cilia, but they also occur on prokaryotes, which are organisms with cells that do not contain a nucleus. Some eukaryotes that use cilia and flagella to move are also found in ferns, on algae, on bacteria and inside many animals. This adaptation originally allowed independent cellular creatures, such as paramecia, to move around in search of food, rather than wait until food came to them. Cells that are part of larger systems have continued to use cilia to their advantage.

What Are the Pros and Cons of Genetically Engineered Food

Genetically engineered food, also known as Genetically Modified or GM food, is food that has been altered at the genetic level to produce a better tasting, longer lasting, or more resistant product. Vegetables and other crops are the most common type of genetically engineered food. Corn, for example, has been altered to be naturally insect-resistant, while tomatoes have been modified to slow down the rotting process. Genetically engineered food has its pros and cons, which include:

PROS

1. Genetically engineered food is cost effective. Because it is designed to resist pests and prosper under non-optimal conditions, it can also help people in areas where regular crops would not prosper. Large savings in production may lead to financial gain and help fight poverty.
2. Genetically engineered food can be naturally pest-resistant and thus reduce the need for additional chemicals, pesticides, and other dangerous additives.
3. Genetically engineered food may help reduce world hunger, at least in theory. As new species are altered to grow faster or more effectively, they can be used to feed poor nations or chosen for countries where crops may not normally prosper because of less than desirable environmental conditions. Some companies now claim to be producing crops that can help against certain diseases or provide specific nutrients, such as milk proteins and iron, which would otherwise not be available to some populations.

CONS

1. Genetically engineered food is too new for us to know if it may have an effect on the human body. Modifying the essence of a food may also alter the dynamics of it in ways not known. Since many of the alterations include adding chemical properties to the crops, some people fear what effect those same chemicals may have on us.
2. Poor countries will not have easy access to genetically engineered food unless directly given to them, which means that the world's richest nations will control the market. This may result in a high dependency on the side of the poor nations, which will in turn lead to a broken economy.

What is a Faraday Cage

It's very likely you woke up this morning in a Faraday cage, made your breakfast in another Faraday cage, and drove a Faraday cage to work. Depending on your particular job, you may have spent much of your day in front of yet another Faraday cage.

The concept of a Faraday cage is logically attributed to Michael Faraday, an 19th Century pioneer in the field of electromagnetic energy. Faraday studied the work of earlier scientists such as Benjamin Franklin and theorized that electromagnetic waves naturally flowed around the surface of conductive materials, not through them. For example, if a metal box containing a mouse were placed directly in the path of an electrical current, the electricity would flow over the box but not into the compartment with the mouse. The mouse would not be electrocuted. Such a box would be considered a Faraday cage.

The important concept to remember is that a Faraday cage acts as a shield against the effects of electromagnetic energy. When a car is struck by lightning, the metal frame becomes a Faraday cage and draws the electricity away from the passengers inside. A microwave oven's door has a screen which prevents electromagnetic energy from escaping into the room. Electronic parts which generate radio frequencies are often protected by Faraday cages called RF shields. Even a concrete building reinforced with lead or rebar can be considered a Faraday cage.

Few consumers of electronic products would ever ask the sales clerk for a Faraday cage, but designers and engineers understand the importance of electromagnetic shielding very well. Whenever sensitive electronic parts are used in machinery, some form of shielding is generally in place, whether it be the machine's metal shell, a capsule or a grounding wire. If the electronic parts generate electromagnetic energy of their own, a Faraday cage must be used to shield users from excessive exposure. This is why cell phone use is often discouraged in hospitals or other public places with electronic equipment. Unshielded equipment may be exposed to the microwave energy created by cell phones or other radio transmitters.