What is the function of the cell membrane?

The short answer is to protect the inside of a cell by keeping certain substances out and allowing certain substances in. Another function is to help the cell maintain its shape. A cell membrane is not made of one solid piece but made mostly from compounds of proteins and phospholipids. The phospholipids make up the bulk of the membrane and the proteins are found around tiny holes in the membrane that helps it move compounds in and out of the cell.

Sources:

http://biology.about.com/od/cellanatomy/ss/cell-membrane.htm

http://www.biology4kids.com/files/cell_membrane.html

Image source:

http://en.wikipedia.org/wiki/File:Cell_membrane_detailed_diagram_4.svg

Be the first to comment - What do you think?  Posted by Admin - 12/08/2013 at 9:25 pm

Categories: Biology   Tags:

Who invented the toilet?

While Thomas Crapper was indeed a 19th century plumber in England, he did not invent the modern flushing toilet. That honor goes to Sir John Harrington who came up with a prototype for Queen Elizabeth I’s palace in the 16th century. Also more than 60 years before Crapper was even born, Alexander Cummings received the first patent for a flushing toilet in 1775.

Thomas Crapper was an interesting man though. He became an apprentice plumber in his teens and owned his own plumbing business by 25. He did come up with several patents for improving plumbing, some of which were for flushing. So was it merely an ironic coincidence that a man by the name of Crapper did a lot of work on toilets? Yeah, probably so.

Now is it possible that the term “crapper” being synonomous for toilet originated because this guy was a well-to-do plumber? You might think so, but it’s not likely. Webster’s Collegiate Dictionary says the term dates back to 1846, well before Thomas became the master plumber that we all know and love him for.

Sources: toiletmuseum.com, urbanlegends.about.com/od/factoid1/p/thomas_crapper.htm
Image source: nodrips.blogspot.com/2011/01/toilets-in-age-of-thomas-crapper.html

Be the first to comment - What do you think?  Posted by Admin - 01/18/2012 at 1:08 pm

Categories: General Science   Tags:

Do people live in Antarctica?

The general answer is no, as there are no permanent residents of Antarctica. Several contries however, do maintain permanent research stations with scientists and support personnel that number up to 5,000 in the summer and about 1,000 in the winter. Most researchers do not stay through the winter but those that do are typically there on one-year assignments.

The United States has two primary bases there: Amundsen-Scott South Pole Station and McMurdo Station.

An interesting aside: the South Pole has no solar time so a station there could theoretically be in any of the world’s 24 time zones. They use New Zealand time (UTC +12) since all flights to the continent come from Christchurch.

Image source: http://wwp.greenwichmeantime.com/time-zone/antarctica/antarctica.jpg

Be the first to comment - What do you think?  Posted by Admin - 01/08/2012 at 12:11 am

Categories: Ecology, General Science   Tags:

How fast is the speed of light?

Speed of Light

The speed of light, typically noted as c in math and physics formulas is 299,792,458 meters per second (186,282 miles per second). Note, this figure is for the speed in a vacuum as light will propagate at different speeds through different mediums.

Here’s the speed of light compared to other fast things (in miles per hour):

Unmanned spacecraft, Helios 1 and 2. 157,082 mph. Light is 4,269 times faster than the fastest vehicle ever built by man.

Manned spacecraft, Apollo 10. 39,665 mph. Light is almost 17,000 times faster.

Jet, SR-71 Blackbird, the world’s fastest jet has traveled at 2,193 mph. Light is 305,799 times faster.

Sound: 768 mph. Very much slower than light. 873,000 times slower.

World’s fastest car, Bugatti Veyron. 267 mph. Pretty fast, but compared to light, it’s 2,511,673 times slower.

World’s fastest bird, Spine-tailed Swift, 171 mph. This is crazy fast for a bird. But almost 4 million times slower than light.

World’s fastest mammal, the cheetah has been clocked at 71 mph. 9.4 million times slower than light.

World’s fastest insect, the dragonfly. One species has been measured at 36 mph.

World’s fastest man, Usain Bolt. While faster than anyone else on the planet at 23 mph, he’s still 29 million times slower than light.

Be the first to comment - What do you think?  Posted by Admin - 01/04/2012 at 10:49 am

Categories: Physics   Tags:

Do people eat spiders in their sleep?

Wolf Spider

Source: www.spyderwood.com

The short answer: no. Is it possible that of the seven billion people in the world, all sleeping at some point during a 24 hour period, some might accidentally eat a spider during their sleep? Sure, it’s possible but very unlikely.

The source of this urban legend is generally unknown but a plausible explanation (from snopes.com) is this. In the early days of the Internet, a columnist named Lisa Holst wanted to prove a point that many people would believe all sorts of crazy things if they saw it in a list of “facts,” that had been emailed to them. She completely made up a list of false facts to prove how easily they would be accepted by a certain number of gullible recipients in the (then relatively new) world of email. One of her facts was that the average person swallows X number of spiders in their sleep every year. Read more…

Be the first to comment - What do you think?  Posted by Admin - 01/03/2012 at 9:51 am

Categories: Biology, Entomology   Tags:

Why does hair turn gray?

Eumelanin and Pheomelanin in hair follicles

Cross Sections of a hair and follicle. Source: www.ohiohealth.com

To understand this, we should first answer what causes hair color to begin with. All hair, whether on your head, your arms, or your cat’s tail has pigment cells called melanocytes. These melanocytes produce a pigment called melanin- more specifically, the chemicals eumelanin and pheomelanin. Hair with more eumelanin will be darker (brownish to black) and hair with more pheomelanin will have a red/orange/yellow tint. Hair with less of either will be lighter.

These melanocytes also pass this pigment to cells called keratinocytes (which produce hair’s main component, the protein keratin). When the keratinocyte cells die, they keep the melanin which is what is visible and gives hair its color.

As we get older, the melanocytes get less active, thus producing less pigment and making your hair lighter. Eventually all the melanocyte cells die and there are none left to produce any color.

So what are the factors that control this production of pigment? Many are genetic. Alleles of the recently-discovered MC1R gene have been shown to produce red hair in mammals. Other genes, many as yet unidentified, are likely responsible for other hair colors. According to Laurence Meyer, a dermatologist at the University of Utah, “Generally speaking, among Caucasians 50 percent are 50 percent gray by age 50. There is, however, wide variation.” Of course, these percentages are different for different ethnic groups, which further emphasize the role genetics play in the color of your hair.

References:
About.com: http://chemistry.about.com/od/howthingsworkfaqs/f/why-does-hair-turn-gray.htm
Scientific American: http://www.scientificamerican.com/article.cfm?id=why-does-hair-turn-gray
Image: http://www.ohiohealth.com/mayo/images/image_popup/sn7_skinlayers.jpg

1 comment - What do you think?  Posted by Admin - 12/30/2011 at 9:30 am

Categories: Biology   Tags:

Who was the first person in space?

Yuri Gagarin Newspaper Headline

Yuri Gagarin was the first person in space when he orbited the Earth on April 12, 1961. He was only 25 years old at the time. Gagarin was a Russian cosmonaut. A cosmonaut is what the Russians call their astronauts. And for you really young readers, a Russian is what we used to call someone who was from what we used to call Russia, or the former Soviet Union.

Yuri’s orbit was made in the Vostok I and took just one hour and 48 minutes to complete. He became an international hero after his flight. For anyone interested, I encourage you to check out Wikipedia’s page on Yuri Gagarin. He was a very accomplished pilot and sadly, was killed in a jet crash when he was only 34 years old.

Yuri Gagarin in his cosmonaut suit

Image sources:

http://un-dx.ucoz.com/yuri-gagarin-news11.jpg

http://www.eliteoftheworld.com/images/gallery/1306195171yuri-gagarin-2.jpg

Be the first to comment - What do you think?  Posted by Admin - 12/27/2011 at 10:24 am

Categories: Physics   Tags:

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