About.com Biology

DNA Structure

Sat, 07 Nov 2009 05:00:30 +0000


DNA Double Helix NASA

With the popularity of many crime scene investigation shows, DNA has become a household term. It is the basic building block for our genetic structure and contains all the information needed for growth, development and reproduction. With the exception of identical twins, each person's DNA is unique. So, what exactly is DNA? DNA or deoxyribonucleic acid is a type of macromolecule known as a nucleic acid. It is shaped like a twisted double helix and is composed of long strands of alternating sugars and phosphate groups, along with nitrogenous bases (adenine, thymine, guanine and cytosine). DNA is organized into chromosomes and housed within the nucleus of our cells.

Learning about DNA can be interesting and fun. Constructing DNA models is a great way to learn about DNA structure, function and replication. You can also discover how to extract DNA from a banana or make a candy DNA model.

DNA Structure originally appeared on About.com Biology on Saturday, November 7th, 2009 at 05:00:30.

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Learning Language in the Womb

Fri, 06 Nov 2009 16:16:21 +0000


Image: Canwest News Service

Did you know that babies learn elements of language before they are even born? While still in their mother's womb, fetuses can memorize sounds and melodies in both music and language. Researchers have now discovered that babies reproduce intonations of language patterns that they have memorized while in the womb.

This study centered around the analysis of crying melody patterns of French and German infants. It was discovered that French newborns produce rising crying patterns, while German newborns produce falling crying patterns. As researcher Angela Friederici explains, "In French, a lot of words have stress at the end, so that the intonation rises, while in German, it is mostly the opposite." This study shows that newborns produce sounds with intonation patterns that are familiar. Evidence from additional studies also suggests that by the time a baby reaches four months old, intonations of the mother tongue are firmly fixed in the brain.

Learn more about this discovery:

Language Learning Starts From The Womb Science Daily

Learning Language in the Womb originally appeared on About.com Biology on Friday, November 6th, 2009 at 16:16:21.

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Army Ant Adoption

Wed, 04 Nov 2009 16:52:41 +0000


Soldier Army Ants Image: Daniel Kronauer/Harvard University

In army ant colonies everything begins and ends with the queen. The queen produces eggs that develop into soldiers or workers. The worker ants forage for food and take care of the queen's brood, while the soldier ants defend the colony. When the queen dies, the colony vanishes. Researchers from the Harvard Museum of Comparative Zoology and the University of Copenhagen have determined what happens to army ant colony members once the queen is gone.

It appears that individual ants from most queenless colonies are incorporated into nearby colonies rather than killed. Of the ten queenless colonies studied, seven were adopted into other colonies. One colony remained on its own and produced a small number of winged males with the ability to venture off to find young queens.

Learn more about this discovery:

Orphan Army Ants Adopted Harvard University

More Information on Ants:

Army Ant Adoption originally appeared on About.com Biology on Wednesday, November 4th, 2009 at 16:52:41.

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Pumpkin Rinds Inhibit Microbes

Fri, 30 Oct 2009 13:00:43 +0000


FreeDigitalPhotos.net

Pumpkins are not just good for making Jack-o'-Lanterns or pumpkin pie. Researchers revealed that pumpkin rinds contain proteins that inhibit the growth of microbes. These antimicrobial proteins could be used to develop treatments for fungal diseases that effect humans and plants.

In the study, pumpkin rind proteins were shown to restrict the growth of the fungus that induces vaginal yeast infections and diaper rash. Another encouraging discovery was that treating the fungus with the pumpkin protein appeared to cause no toxic effects. The protein was also effective at prohibiting fungal growth in plant crops.

Learn more about this discovery:

Pumpkin Skin May Scare Away Germs Science Daily

Pumpkin Rinds Inhibit Microbes originally appeared on About.com Biology on Friday, October 30th, 2009 at 13:00:43.

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The Origin of House Dust

Fri, 30 Oct 2009 12:53:18 +0000


Dust Mites Image: Eric Erbe/USDA

Dusting is not a very popular household cleaning chore but is necessary due to the accumulation of dust and dirt indoors. Scientists in Arizona are reporting that they have found the answer to the question of where indoor household dust originates. Most of the indoor dust comes from outdoors.

Household dust is composed of various particles including dust mites, textile fibers, parts from dead insects, human and animal hair, mold spores, bacteria, and dead human skin cells. Dust is also composed of particles that can be blown or tracked indoors from outside including sand, dirt, pollen grains, lead, and arsenic. The researchers found that over 60 percent of indoor household dust comes from outdoors.

Learn more about this discovery:

Where Does All This Dust Come From? Science Daily

The Origin of House Dust originally appeared on About.com Biology on Friday, October 30th, 2009 at 12:53:18.

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10 Facts About Cells

Tue, 27 Oct 2009 06:00:30 +0000


Connective Tissue Cells Dr. Cecil Fox/National Cancer Institute

Cells are the fundamental units of life. Whether they be unicellular or multicellular life forms, all living organisms are composed of and depend on cells to function normally. Not all cells however are alike. There are two primary types of cells: prokaryotic cells and eukaryotic cells. Eukaryotic cells have a true nucleus (distinct area that houses DNA) and are generally more complex than prokaryotic cells. Examples of eukaryotic cells include animal and plant cells. Bacteria and archaeans are prokaryotic cells. Some interesting facts about cells include:

There are anywhere from 75 to 100 trillion cells in the body.
There are more bacterial cells in the body than human cells.
Prokaryotes are the most primitive forms of life on earth.
Cells have varying life spans.
Cells commit suicide.

For additional information about cells see: Cell Structure, Cellular Respiration and Cell Anatomy Quiz.

10 Facts About Cells originally appeared on About.com Biology on Tuesday, October 27th, 2009 at 06:00:30.

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Are You A Biology Whiz?

Sat, 24 Oct 2009 18:25:46 +0000


Quick - Identify the organism in the image.

Are you a Biology Whiz? Do you think you know all there is to know about biology? If so, then biology games and quizzes can be an effective way to test your knowledge about the fun-filled world of biology. If you've ever wanted to test your knowledge of biology concepts, take the biology quizzes/games below and find out how much you really know. Good luck!

See: Biology Games and Quizzes for additional games and quizzes.

Are You A Biology Whiz? originally appeared on About.com Biology on Saturday, October 24th, 2009 at 18:25:46.

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Replacing Lost Bone

Sat, 24 Oct 2009 18:08:26 +0000

Researchers at Tel Aviv University hope to perfect a technique that will allow humans to replace lost bone. The researchers have developed a new biologically active 'scaffold' which may one day help replace lost or missing bone. Prof. Meital Zilberman from the Department of Biomedical Engineering at Tel Aviv University notes, "The bioactive agents that spur bone and tissue to regenerate are available to us. The problem is that no technology has been able to effectively deliver them to the tissue surrounding that missing bone."

The scaffolding works by connecting tissues with one another as it releases the bioactive agents where the new bone growth is needed.

To learn more about this discovery:

Biologically Active 'Scaffold' May Help Humans Replace Lost Or Missing Bone Science Daily

Replacing Lost Bone originally appeared on About.com Biology on Saturday, October 24th, 2009 at 18:08:26.

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New Species of Giant Spider Discovered

Wed, 21 Oct 2009 20:47:20 +0000


Small Male (red) Golden Orb Weaver Spider on Female Image: M. Kuntner

Giant golden orb weaver spiders are well-known for their web spinning capabilities. They produce the largest orb webs which can be as large as 3 feet in diameter. Researchers have announced the discovery of a new species of giant golden orb weavers found in Africa and Madagascar. This species, Nephila komaci, is very rare and it is feared that the spiders are an endangered species.

An interesting fact about giant golden orb weavers is that only the females of the species are enormous. Females have a body length of about 1.5 inches with a leg span between 4 to 5 inches. The researchers believe that the females have evolved over time in their tropical environment to become larger as a result of natural selection. The males however did not experience this same size change and remained at least five times smaller than the females.

Learn more about this discovery:

Scientists Discover Largest Orb-weaving Spider Science Daily

New Species of Giant Spider Discovered originally appeared on About.com Biology on Wednesday, October 21st, 2009 at 20:47:20.

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How To Make a Lung Model

Sat, 17 Oct 2009 06:00:41 +0000


Image: Rod Nave

Constructing a lung model is an excellent way to learn about the respiratory system and lung function. The lungs provide a place for gas exchange between air from the outside environment and gases in the blood. The respiratory and cardiovascular systems work together to obtain and circulate gases throughout the body. The heart pumps de-oxygenated blood to the lungs through the pulmonary arteries. Oxygen is picked up in the lungs and the newly oxygenated blood returns to the heart via the pulmonary veins.

Breathing is controlled by a region of the brain called the medulla oblongata. The brain sends signals to muscles in the diaphragm causing them to contract. This contraction causes inhalation and creates low pressure in the chest cavity. As the diaphragm relaxes, pressure within the chest cavity increases resulting in exhalation. In this lung model demonstration, structures of the respiratory system will be represented as follows:

plastic bottle = chest cavity
plastic tubing = trachea
Y-shaped connector = bronchi
balloons inside bottle = lungs
balloon covering bottom of bottle = diaphragm

For additional information about biology models and experiments see: DNA Models, How To Make a DNA Model Using Candy and How To Extract DNA From a Banana.

How To Make a Lung Model originally appeared on About.com Biology on Saturday, October 17th, 2009 at 06:00:41.

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