What Are Chromosomes?
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| Image: Dream Designs FreeDigitalPhotos.net | |
A chromosome is a long, stringy aggregate of genes that carries heredity information (DNA). Chromosomes determine everything from hair color and eye color to sex. Chromosomes are located within the nucleus of our cells and are formed from condensed chromatin. During cell division, chromatin fibers become coiled into chromosomes with each chromosome having two identical copies known as sister chromatids. Sister chromatids are joined together at their central region called the centromere.
Sometimes chromosome abnormalities may occur as a result of chromosome mutations. These mutations may be brought on by mutagens (like radiation) or by problems that occur during cell division. One type of mutation is caused by chromosome breakage. The broken chromosome fragment may be deleted, duplicated, inverted, or translocated to a non-homologous chromosome. Another type of mutation occurs during meiosis and causes sex cells to have either too many or not enough chromosomes. For additional information on chromosomes, see:
Science Project Ideas
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Have a science project that's due and don't know where to start? Don't worry, most students find it difficult to get started on a project. So where do you get ideas for biology science fair projects? The answer is from almost anywhere. The key is to start with a question that you would like to find an answer to, and use the scientific method to help you answer it. When choosing a science fair project topic, make sure that you select a topic that you are interested in. Then narrow this topic down to a specific question.
The Biology Science Fair Project Ideas page will help you find ideas for projects related to animals, plants and the human body. Another good resource to assist you in learning how to develop, arrange, and display your science project is the science project help guide. For information on additional biology activities and experiments, see:
Flying Snakes
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| © Jake Socha | |
Did you know that some snakes fly? Well, it's more like gliding. Researchers from Virginia Tech are studying five species of snake from Southeast and South Asia to determine just how these reptiles accomplish this feat. The researchers used video cameras to record the animals in flight and create 3-D reconstructions of the snakes' body positions. The studies showed that the snakes can travel up to 24 meters from a branch at the top of a 15-meter-tall tower with constant velocity and without simply dropping to the ground.
From the reconstructions of the snakes in flight, it was determined that the snakes never reach what is known as an equilibrium gliding state. This is a state in which the forces created by their body movements exactly counteract the forces pulling down on the snakes. According to researcher Jake Socha, "the snake is pushed upward -- even though it is moving downward -- because the upward component of the aerodynamic force is greater than the snake's weight." This effect however is temporary, ending with the snake landing on another object, such as a branch, or on the ground.
Learn more about this study:
- Flying Snakes, Caught on Tape Science Daily
What Are Prokaryotes?
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| Credit: Janice Carr/CDC | |
Prokaryotes are single-celled organisms that are the earliest and most primitive forms of life on earth. As organized in the Three Domain System, prokaryotes include bacteria and archaeans. Prokaryotes are able to live and thrive in various types of environments including extreme habitats such as hydrothermal vents, hot springs, swamps, wetlands, and the guts of animals.
Prokaryotic cells are not as complex as eukaryotic cells. They have no true nucleus as the DNA is not contained within a membrane or separated from the rest of the cell, but is coiled up in a region of the cytoplasm called the nucleoid. To learn more about prokaryotic cell structure and reproduction, see Prokaryotes.
Holiday Spending Causes Pain
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Holiday shoppers in the United States are prepped for the holiday shopping season that typically begins on Black Friday, the day after Thanksgiving. This frenzied season for shopping however, adds to what is known as purchase pain. Researchers have discovered that shoppers known as spendthrifts and tightwads experience different levels of psychological pain when purchasing items. Using functional magnetic resonance imaging (fMRI) experiments to examine areas of activity in the brain, researchers discovered that paying with cash triggers more intense purchase pain in tightwads than in spendthrifts. As a result, tightwads spend much less when purchasing with cash. However, when buying gifts, tightwads and spendthrifts spend almost the same amount of money.
Why is it that spending money on gifts is about the same for tightwads and spendthrifts? According to researcher Scott Rick, "It may be that spending money on someone else lessens the pain of making purchases. Alternatively, spending on gifts may be just as painful as usual for tightwads, but the necessity of buying gifts overwhelms the influence of that pain on spending decisions." It was also discovered that spendthrifts spend considerably more on coffee, clothes and entertainment than do tightwads.
Learn more about this study:
- Tightwads and Spendthrifts Science Daily
Action Games Improve Visual Attention
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| Microsoft | |
Can playing certain video games improve visual attention? Researchers from the University of Rochester believe it can. A person's level of visual attention relies on the brain's ability to process relevant visual information and suppress irrelevant information. In studies, video gamers consistently outperform their non-gamer counterparts when performing visual attention related tasks. It is important to note that the type of video game played is a significant factor regarding visual attention enhancement. Games such as Halo, which require rapid responses and divided attention to visual information, increase visual attention, while other types of games do not.
Lead author, Bjorn Hubert-Wallander states that visual attention is, "an ability that is especially emphasized during visually demanding activities such as driving a car or searching for a friend's face in a crowd. Just as drivers have to focus on the road, other cars, and potential obstacles while ignoring other information, modern action games place heavy attentional demands on players." The researchers believe that action games could have real-world applications in areas such as military training, visual impairment and education.
Learn more about this study:
Protein Synthesis - Translation
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| Credit: National Human Genome Research Institute | |
How are proteins made? Protein synthesis occurs by the processes of transcription and translation. In transcription, the genetic code for protein production contained within DNA is transcribed to an RNA version of the code known as messenger RNA (mRNA). The messenger RNA molecule is then translated to produce proteins.
While transcription takes place within the nucleus of our cells, actual protein production through translation occurs in the cytoplasm. After leaving the nucleus, mRNA undergoes several modifications before being translated. Cell structures known as ribosomes along with another RNA molecule called transfer RNA (tRNA) work together to translate mRNA. A growing amino acid chain, also called a polypeptide chain, is produced in the process. The newly formed polypeptide chain undergoes several modifications before it becomes a fully functioning protein. Many copies of a protein can be made from one mRNA molecule because several ribosomes can translate the same mRNA molecule at the same time. To learn more about protein synthesis and the process of translation, see Protein Synthesis - Translation.
Turkey Talk
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| Keith Weller/USDA | |
According to the National Turkey Federation, 95 percent of Americans surveyed eat turkey during Thanksgiving. About 45 million turkeys are consumed during this time, which translates to about 675 million pounds of turkey. Before sitting down to enjoy that holiday meal, I believe it is appropriate to pay tribute to this splendid bird by discovering some interesting turkey facts.
Turkeys have interesting features that stand out upon first glance. One of the first things people notice about turkeys are the red, fleshy stretches of skin and bulbous growths located around the head and neck region. These structures are the:
- Caruncle-fleshy bumps on the head and neck
- Snood-long flap of flesh that hangs over the beak
- Wattle-red skin that hangs from the neck
The wild turkey is the only type of poultry native to North America and is the ancestor of the domesticated turkey. Although wild and domesticated turkeys are related, there are some differences between two. While wild turkeys are capable of flight, domesticated turkeys cannot fly. Wild turkeys typically have dark colored feathers, while domesticated turkeys are commonly bred to have white feathers.
More About Turkeys:
Chocolate Is Good For Your Heart
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Chocolate has many health benefits, one of which includes reducing the risk of heart failure. Researchers have now discovered how chocolate protects against heart disease. Cocoa lowers blood pressure by inhibiting the enzyme ACE. This enzyme helps to raise blood pressure in the body. In the study, chocolate was found to lower ACE activity as effectively as certain ACE inhibiting medications that are prescribed to treat hypertension.
The researchers state that the active substances in cocoa, catechins and procyanidines, are what help to regulate blood pressure. This is just the latest in a string of discoveries about the beneficial effects of eating chocolate. Previous studies have shown that chocolate acts as an antioxidant, increases blood flow to the brain, and even acts a painkiller.
Learn more about this discovery:
- Why Chocolate Protects Against Heart Disease Science Daily
From Skin Cells to Blood Cells
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| Image: Renjith Krishnan FreeDigitalPhotos.net | |
Researchers from McMaster University have succeeded in creating human blood from adult human skin cells. What is unique about this discovery is that the adult skin stem cells have been converted directly to blood stem cells without having to be changed into pluripotent stem cells first. Pluripotent stem cells have the ability to change into almost any type of cell in the body.
Dr. Cynthia Dunbar of the National Institutes of Health states that this unique approach, "detours around the pluripotent stem cell stage and thus avoids many safety issues, increases efficiency, and also has the major benefit of producing adult-type l blood cells instead of fetal blood cells, a major advantage compared to the thus far disappointing attempts to produce blood cells from human ESCs (embryonic stem cells) or IPSCs (induced pluripotent stem cells)." The researchers project that this study could lead to new treatments for people suffering from cancer and certain blood conditions. They believe that by producing blood cells from a patient's own skin, there will be no need for bone marrow transplant matching.
Learn more about this study:
- Scientists Turn Skin Cells Directly Into Blood Cells Science Daily