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Test Your Cardiovascular System Knowledge

Sat, 06 Feb 2010 06:00:37 +0000


Blue = oxygen-poor blood Red = oxygen-rich blood Image Credit: MedValet

The heart is the organ of the cardiovascular system which supplies blood and oxygen to all parts of the body. The cardiovascular system consists of the heart and blood vessels. Can you identify the heart structure indicated by the number 4 in the image? This structure receives oxygen-rich blood from the left atrium and pumps it to the aorta. The aorta carries and distributes blood to the rest of the body.

A. Right Ventricle
B. Left Ventricle
C. Pulmonary Artery
D. Right Atrium

Test your knowledge of the cardiovascular system. Take the Cardiovascular System Quiz! Need a quick review before taking the quiz? Visit: Anatomy of the Heart and The Heart and the Circulatory System.

Test Your Cardiovascular System Knowledge originally appeared on About.com Biology on Saturday, February 6th, 2010 at 06:00:37.

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Soy Chicken

Fri, 05 Feb 2010 10:34:01 +0000


Credit: Christian Basi/University of Missouri

University of Missouri scientists have succeeded in creating a soy substitute for chicken that is consistent with the actual look and feel of the meat. Soy products have become increasingly popular due to the health benefits they provide. Some of these benefits include cholesterol reduction and prevention of certain types of cancer.

It took some time to create the soy chicken as initial tests produced a product that was similar in texture to chicken, but according to researcher Fu-Hung Hsieh, "tasted more like turkey." By adding extra fiber and increasing the moisture content of the soybean paste, the researchers were able to create a soy product that closely resembles chicken in both its stringy texture and taste. In creating this more "realistic" chicken substitute, it is hoped that more people will choose soy chicken as a healthier alternative to chicken.

Learn more about this study:

It Looks, Feels and Tastes Like Chicken (Science Daily)

Soy Chicken originally appeared on About.com Biology on Friday, February 5th, 2010 at 10:34:01.

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Black History: Science

Wed, 03 Feb 2010 15:36:22 +0000


Daniel Hale Williams Public Domain Image

Did you know that the first successful open heart surgery was performed by an African American? Dr. Daniel Hale Williams performed this operation in the summer of 1893, at a time when performing surgery on a person with internal injuries was not done due to high risk of infection. According to the Black Inventor Online Museum, Hale's operational and antiseptic procedures used during this surgery would be used as standards for future surgeries of this type.

African Americans have made significant contributions to various areas of science. They have developed synthetic drugs for the treatment of chronic ailments, helped to invent laser devices for the treatment of cancer patients, and developed treatments for various diseases including leprosy, cancer, and syphilis. Learn about the accomplishments and contributions African American scientists have made to science and humanity. If you would like to test your knowledge of African Americans in science, take the African Americans in Science Quiz!

Black History: Science originally appeared on About.com Biology on Wednesday, February 3rd, 2010 at 15:36:22.

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Sleepy High School Students

Sat, 30 Jan 2010 05:00:49 +0000


Image: graur razvan ionut FreeDigitalPhotos.net

The Centers for Disease Control and Prevention recently conducted a study to help assess why there are so many sleep deprived high school students. In the survey, students were asked how much sleep they get on an average night. The most common answer indicated that not enough students get the proper amount of sleep. Prior studies have shown that those in their teens need on average nine hours of sleep per night. Eight hours of sleep is considered the borderline minimum for teens. The study found that most of the students got less than eight hours of sleep per night.

In a search for answers as to why high school students are so sleep deprived, researchers point to studies that suggest that computers may contribute to the problem. These studies have shown that the blue light emitted by computer screens may alter a person's internal biological clock.

Sleeplessness can be a serious condition. Without proper sleep, teens may have more trouble learning in school. This certainly does not help when studying for biology exams. Lack of sleep also contributes to poor judgment and even one night of not enough sleep can impair the body's chemical balance.

Learn more about this study:

Slumber by the Numbers (Science News for Kids)

Sleepy High School Students originally appeared on About.com Biology on Saturday, January 30th, 2010 at 05:00:49.

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Are Antioxidants Always Good For Us?

Fri, 29 Jan 2010 19:04:47 +0000

A study reveals surprising evidence that antioxidants aren't always the panacea that we may think they are. While they have many positive benefits, recent studies at Kansas State University also suggest that they can cause harm in some circumstances. Too much of a good thing may be bad.

Scientists at the Kansas State University Cardiorespiratory Exercise Laboratory have studied ways to improve oxygen delivery to muscles during physical activity through the use of antioxidants. Steve Copp, a researcher in the lab states, "One of the things we've seen in our research is that you can't just give a larger dose of antioxidants and presume that there will be some sort of beneficial effect. In fact, you can actually make a problem worse." The researchers found that antioxidants can sometimes impair the function of muscles. Too many antioxidants can negatively impact the levels of oxidants, like hydrogen peroxide, which actually help to dilate blood vessels and increase blood and oxygen flow to muscles.

Learn more about this study:

Antioxidants Aren't Always Good for You (Science Daily)

Are Antioxidants Always Good For Us? originally appeared on About.com Biology on Friday, January 29th, 2010 at 19:04:47.

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Polar Fibers

Thu, 28 Jan 2010 20:18:24 +0000


Cell in Anaphase of Mitosis Courtesy: National Human Genome Research Institute

Polar fibers are microtubules that play a very important role in the cell division processes of both mitosis and meiosis. Shaped like hollow rods, polar fibers are spindle fibers that extend from the two poles of a dividing cell and help to manipulate and separate chromosomes.

For example, during metaphase of mitosis, polar fibers extend from the cell poles to align chromosomes at the metaphase plate. In anaphase, polar fibers connected to chromosomes shorten thereby separating sister chromatids and pulling them toward the spindle poles. Polar fibers not connected to chromosomes lengthen and elongate the cell.

Polar Fibers originally appeared on About.com Biology on Thursday, January 28th, 2010 at 20:18:24.

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Sexual Versus Asexual Reproduction

Sat, 23 Jan 2010 05:00:07 +0000


E. coli bacteria reproducing asexually. Image: Janice Carr/CDC

Which type of reproduction is better, sexual reproduction or asexual reproduction? A study of a species of both sexual and asexual New Zealand freshwater snails, Potamopyrgus antipodarum, suggests that organisms that reproduce sexually have less genetic mutations than those that reproduce asexually. This is thought to be the reason why sexual reproduction is the more common form of reproduction among living organisms.

There are advantages to both types of reproduction. Organisms that reproduce asexually are able to produce numerous offspring without costing the parent a great amount of energy or time. On the other hand, sexual reproduction introduces genetic diversity into a population. Evidence from the study demonstrates that sexual reproduction helps organisms reduce the amount of accumulated DNA mutations. According to the study, the snails that reproduced sexually accumulated DNA mutations at half the rate of the snails that reproduced asexually.

Learn more about this study:

Value of Sexual Reproduction Versus Asexual Reproduction (Science Daily)

Sexual Versus Asexual Reproduction originally appeared on About.com Biology on Saturday, January 23rd, 2010 at 05:00:07.

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Blueberry Juice and Memory

Fri, 22 Jan 2010 11:59:34 +0000


Image: Michelle Meiklejohn / FreeDigitalPhotos.net

Blueberries contain high levels of naturally occurring antioxidants that protect the body against cell damaging free radicals. Previous animal studies have shown that blueberry juice improves memory and even reduces high blood sugar in animals. Researchers are now reporting that blueberry juice improves memory in humans.

The study was conducted with elderly adults who were experiencing early memory decline. The results showed that drinking 2-2 1/2 cups of store bought blueberry juice a day improves memory. Participants who consumed blueberry juice not only showed improvement on memory tests, but their overall learning ability was enhanced as well.

Learn more about this study:

Blueberry Juice Improves Memory in Older Adults Science Daily

Blueberry Juice and Memory originally appeared on About.com Biology on Friday, January 22nd, 2010 at 11:59:34.

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What Is a Haploid Cell?

Thu, 21 Jan 2010 05:00:23 +0000


Four haploid cells are produced from one parent cell. © John C. Glase

A haploid cell is a cell that contains one complete set of chromosomes. Our sex cells (sperm and eggs) are haploid cells that are produced by meiosis. When sex cells unite during fertilization, the haploid cells become a diploid cell.

The haploid number is the number of chromosomes within the nucleus of a cell that constitutes one complete chromosomal set. This number is commonly abbreviated as n, where n stands for the number of chromosomes. The haploid number will be different for different organisms. In humans, the haploid number is expressed as n=23. Haploid human cells have 1 set of 23 chromosomes.

Would you like to learn more about how haploid cells are produced? Visit:

What Is a Haploid Cell? originally appeared on About.com Biology on Thursday, January 21st, 2010 at 05:00:23.

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Meiosis Animation

Sat, 16 Jan 2010 04:00:17 +0000


Cell in Anaphase II of Meiosis © John C. Glase

Meiosis is a two part cell division process in organisms that sexually reproduce. Through a sequence of steps, the replicated genetic material in a parent cell is distributed among four daughter cells. Meiosis produces gametes with one half the number of chromosomes as the parent cell.

There are two stages of meiosis: meiosis I and meiosis II. At the end of meiosis I, two daughter cells are produced, each with one half the number of chromosomes as the original parent cell. At the end of meiosis II, four daughter cells are produced, each with one half the number of chromosomes as the original parent cell. Meiosis is similar to another cell division process called mitosis. Mitosis produces two cells that are genetically identical to and contain the same number of chromosomes as the parent cell, while meiosis produces four cells that are not genetically identical to the parent cell and contain one half the number of chromosomes. This meiosis animation illustrates the meiotic process and compares it to the process of mitosis.

Would you like to test your knowledge of meiosis? Take the Meiosis Quiz! Need to brush up a bit before taking the quiz? Visit the Meiosis Study Guide and Meiosis Diagrams pages.

Meiosis Animation originally appeared on About.com Biology on Saturday, January 16th, 2010 at 04:00:17.

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