AP Biology class blog for discussing current research in Biology

Tag: Water

Water’s Importance in Photosynthesis in California’s Rice Plants.

A rice farmer would be sloshing through inches of water amid lush, green rice plants in a typical year. But today, the soil lies naked and baking in 35 degrees Celsius or 95 degrees Fahrenheit heat during a devastating drought. The drought started in early 2020, and conditions have progressively gotten worse due to climate change. Low water levels in reservoirs and rivers have forced farmers to slash their water use. One farmer named Rystrom says, “We’ve had to cut back between 25 and 50 percent.” He’s relatively lucky. In some parts of the Sacramento Valley, he says farmers received no water this season in the United States, depending on water rights.

Green rice sheaves planted in a paddy field with long shadows at golden hour in Don Det Laos

California is the second-largest U.S. producer of rice, and over 95 percent of California’s rice is grown within about 160 kilometers of Sacramento. Rice growers in the valley below count on the range of mountains that contain snow to give them enough water for the season. In spring, melting snowpack flows into rivers and reservoirs and then through an intricate network of canals and drainages to rice fields that farmers irrigate in a shallow inundation from April or May to September or October. If too little snow falls in those mountains, farmers like Rystrom are forced to leave fields unplanted. On August 4, Lake Oroville, which supplies Rystrom and other local rice farmers with irrigation water, was at its lowest level on record.

Water is a fundamental part of the process of photosynthesis. Water acts as a reducing agent by providing H+ ions that convert NADP to NADPH. This electron loss must be fulfilled by electrons from some other reducing agent. Hydrogen ions thus released create a chemical potential (chemiosmotic) across the membrane that finally results in ATP synthesis. Photosystem II is primarily known for its use of water to fuel its system, which fuels Photosystem I. Since there is a lack of water in Rystrom’s rice fields, the photosynthesis that would occur in the rice plants cannot happen. If there is no water, there is no photosynthesis, and if there is no photosynthesis, there is no rice. The water allows the rice plant to go through the two Photosynthesis Cycles and then the Calvin cycle, which allows for glucose production. Glucose enables the plant to grow and mature. If the plant cannot grow, there will be no rice.


If the water in the California Valleys continues to plummet, California may not feed half of the world. If and maybe even when that happens, the rice market will not function. Water is so important to these farmers and so crucial to the plants. Is it possible to save the water we have left? Is it possible to reverse our mistakes with global warming to save these farms? I honestly don’t know, but I am willing to do what it takes to preserve what we have left.


An Electrifying Tragedy: The Death of Two Giraffes

On March 2nd, two giraffes were found dead after a thunderstorm in Rockwood, which is a private nature reserve to the west of Kimberely, South Africa. The elder, a five year old female, had a fractured skull as well as a broken ossicone (knoblike horns). These injuries indicate she had died after a direct lightning strike to the head. The second giraffe, a four year old female, was found dead  about 23 feet away from the first giraffe. There are no visible injuries on the second giraffe.

According to Ciska P.J. Scheijen, a student in the Department of Animal, Wildlife, and Grassland Sciences, wrote a paper describing the event. In the African Journal of Ecology, Scheijen describes four ways lightning can kill an animal. It can strike the animal directly, as seen in the older giraffe. It can hit as a “side flash”, which is when the lightning arches into the animal’s body after striking a nearby object. It can also kill through “touch potential” (when the animal is in contact with a lightning-struck object) or “step potential” (when the animal is in contact with lightning-struck ground). It can be inferred that the second giraffe either died from a side flash or step potential.

The giraffes were in an area without trees, making them the tallest things in the area. Knowing this, I bet you and I are wondering the same question. Yes, “Do giraffes get struck by lightning more often than other animals?” The question we all need answered!

There have been a few incidents of giraffes dying of lightning strikes, including one at Disney World’s Animal Kingdom. However, there aren’t any real concrete numbers to determine a conclusion.

Yet, Universiti Putra Malaysia electrical engineer Chandima Gones wrote a paper on animal lightning strikes. He states that “animals with a large separation between their front and back feet…are vulnerable to receive lightning injuries due to the dangerous potential differences that may built up between these feet…” Gomes also writes how taller animals (lik giraffes) are more likely to be victims of side flashes and touch potential if near a lightning struck tree. Without clear cut numbers, though, it’s hard to be sure if giraffes are struck at higher rates than other animals.

But there’s another factor involved in the deaths of the two giraffes back in March that is important. There was a thunderstorm. It was raining.

Water is a covalently bonded molecule containing two hydrogen atoms and one oxygen atom. It is a polar molecule because oxygen is more electronegative than hydrogen. Water has many cool properties. For example, it has an unusually high specific heat, making it harder to change its temperature. Because of this specific heat, it allows living creatures that are largely made of water (like us) to resist drastic changes in the body. Water keeps us alive.

Water is an extremely important molecule for life, including our own. However, when electrocuted, it could very well kill us. We all know we shouldn’t swim in a thunderstorm, but did you know wet skin has 100 times less resistance than dry? That’s right: the amount of water in the body is a huge factor in whether or not you would survive an electrical shock.

Of course, the giraffes didn’t know this. They couldn’t find shelter during the thunderstorm that ultimately led to their own demise. While we may never know if giraffes are more susceptible to electrical shocks by lightning, we do know it’s wise not to mix water and electricity.

Just Add Water: Water’s Importance in Protein Folding

It’s amazing that two hydrogens and an oxygen atom is the basis of life. We are made of 60% of this simple compound, water, and is necessary for repairing cells, tissue, and keeping our organs functioning properly.

According to research published in the Proceedings of the National Academy of Sciences, water is why amino acids fold into their proper shapes. Amino acids are considered the building blocks of life and compose proteins. To delve further into the structure and function of amino acids, click here. Dongping Zhong was the leader of the research group and made the breakthrough discovery of water-protein interaction. He used laser pulses to take snapshots of water molecules moving around a DNA polymerase- the enzyme that helps DNA reproduce. Zhong observed that the water directly interacted with the R groups, the part of the amino acid that attach and detach with other amino acids to fold and direct the protein’s function.


Photo Credit:

It is important to note, however, that water is not the only factor in determining protein shape. Proteins can only fold and unfold in a few different ways, which depend on the amino acids they are comprised of. Nonetheless, water and amino acids themselves are the two reasons for DNA replication and the dozens of other activities that proteins take part in. Zhong’s discovery is just an homage to the larger role of water in everyday life: by just adding water, life runs smoothly.

If this information doesn’t convince you to drink more water, read about the molecular changes our body experiences with lack of water, or when we are dehydrated.

Worried about BPA in your water? Don’t be.

Life developed on Earth because of its rare abundance of water. While we do need water to survive, our water must also be clean and potable, without contaminants or other substances. Recently, the US Geological Survey (USGS) and the US Environmental Protection Agency (EPA) have conducted surveys on our drinking water. The USGS-EPA study has brought to light the disproportionate representation in the media of the toxicity of BPA in drinking water. BPA, or bisphenol A, is used to make epoxy resin and polycarbonate plastic, which is commonly used to make plastic water bottles. BPA in drinking water is commonly covered in the media, even though it was only found in less than 40% of the streams tested in the USGS-EPA study. Contrary to what most people believe, an adult would have to drink over 5,600 gallons of water in one day to reach the safe intake level for BPA set by the EPA. BPA is estrogenic, which means it contains estrone, a toxic estrogen that is naturally produced in the human body. Therefore, concerns of BPA’s toxicity in our drinking water are not nearly as imminent as many people believe.


So, what should we be worried about in our water? The USGS-EPA study found that all streams tested contained at least one toxin. The organizations tested 38 streams and searched for 719 substances. Some streams contained only one substance, yet others contained 162. 66-84% of the toxins found in the streams were results of human activity. Though the USGS and EPA found these toxins, the toxicity of these toxins must be taken into account. This new data sheds light on our drinking water, and takes the spotlight off of BPA.


Original article:

Lead Leads to Neurotoxitity

Have you ever heard of using bottled water to shower? Sounds ridiculous right, but the people of Flint, Michigan need to do this to save their lives. The city of Flint switched their water supply from Lake Huron to the Flint River in April 2014. The river was later discovered to be contaminated. Since the changeover, scientists have linked the high lead levels in children’s blood to the contaminated water. This is a serious problem.

Lead is a highly toxic substance that permanently affects humans’ brains by killing nerve cells. Not only does lead harm kids’ brain processes, it also may cause various future mental diseases, such as Alzheimer’s disease and Schizophrenia. Throughout U.S. history, people have been exposed to lead poisoning through basic everyday mediums, such as paint, water (from lead-contaminated water pipes), and dust. Children who eat paint chips or lick their fingers after coming in contact with products that have a lead component are poisoning themselves. The lead enters into the bloodstream and travels throughout the body, stealthily making itself at home, poisoning the body.

So how does lead poisoning work? Basically, lead disguises itself as zinc. Zinc is needed to anchor proteins that switch genes on and off. When zinc is replaced with lead, the switches cannot function properly, eventually leading to mental diseases.

Lead Poisoning

Scientists have been researching the possibility that lead is transferable in DNA to offspring. This could be devastating to a population of a town like Flint, Michigan, where the mothers who have lead poisoning could pass this on to their babies. The worst part is that there is no cure for lead poisoning.

Because of the devastating effects of lead in bloodstream, governments have debated the topic of legalizing contaminated water as a bioweapon, using lead as the contaminant. Governments in the past have used poisoned water as an assassination method, proving the effectiveness of this strategy.

Preventing lead exposure and poisoning is critical for children’s health and for future generations.


Source Article

For more info on the biowarfare, click here.

Is Mars more like Earth than we think?

Photo of Mars (licensing information here)

For a long time, Mars was thought to be inhabitable.  However, there were always “what ifs” and hopes that one day Mars would be identified as a place where humans could survive and live comfortably.  Recently, researchers found recurring slope lineae (RSL) on the Martian slopes of Mars to be caused by a salty liquid.  We all know the most important aspect of life is water, something no one can live without and life on Earth cannot go on without.  So, if water is crucial to life on Earth, wouldn’t that mean that finding water on Mars points towards the potential for life there as well?

Researchers used the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) aboard the Mars Reconnaissance Orbiter (MRO) in four different locations on Mars where RSL were present.  There were signs of hydrated salts in all four locations during the seasons when RSL are largest and most prominent.  RSL range from .5 to 5 meters wide, but have no limit to how expansive they are downslope.  CRISM analyzes Mars at 3:00 p.m., which in Martian time is the hottest time of the day.  This means that any liquid on the surface of Mars would have evaporated during this time, making it virtually impossible for the CRISM to identify water in its liquid form.  However, hydrated salts precipitate from liquid water, meaning that even if there was no water found there at the time the CRISM analyzed that location, there was water there at one point in time.  The salts associated with RSL are perchlorates, which lower the freezing point of water from 0° C (32° F) to -70° C (-94° F)! Researchers believe this points to a larger possibility for the stability of salt water on Mars.

However, even with all this excitement, researchers are still hesitant to make the claim that there are extremely high odds for the ability of life on Mars.  Due to the low water activity of perchlorates, researchers believe it would be hard for any living organism to survive with this as their only water supply.  Head researcher Lujendra Ojha cautions people who are tempted to jump to the conclusion Mars is now considered habitable for humans.  However, people can still hope that one day Mars may offer a second home to human beings, especially with this new exiting find!


Main articles:

Newly Discovered Exoplanet Has Water


Recently, scientists discovered an exoplanet the size of Neptune that has water. The planet, HAT-P-11b, is roughly four times the size of Earth. It is the smallest known exoplanet to have water, as all the exoplanets outside our solar system that have been found to contain water are the size of jupiter. Scientists were able to discover the presence of water vapor due to its ability to absorb infrared light whenever it passed in front of the star it was orbiting. Currently, the possibility of other worlds containing living conditions similar to our own world is extremely important. We are constantly searching to prove the question “are we alone in the universe”. Only recently, however, have we been able to start finding these exoplanets. With the discovery of each new exoplanet we learn more and more about our universe, and the possibility of other habitable worlds. This newly discovered exoplanet may not be habitable, but the mere presence  of water on it allows us to realize there is a good chance that there are many worlds similar to ours with the possibility of sustaining life.

No More Water Damage?

Have you ever dropped your phone in water? If so you know the horrible feeling of “my phone is ruined”! But this whole situation can now be avoided with a recent discovery made by a British based firm called “P2i“. This firm is known for being the leaders in liquid repellent. The company was established in 2004; it was developed by the United Kingdom government’s defense science and technology laboratory (DSTL). Their new nano-coating is talked about in an article on CNN.


Photo by Kārlis Dambrāns

Photo by Kārlis Dambrāns


Their latest discovery is a liquid repellent nano-coating that provides a watertight solution. Simply spray the nano-coating onto a surface and liquids will be repelled. The trick is a “patented chemical that lowers an objects surface energy”, when the surface energy is lowered the “liquid forms beads upon contact and rolls off with out being absorbed”. This special chemical is extremely small- 50 nanometers wide (which is 1,000 times thinner than a human hair)!

The chemical sprays on clear which makes it invisible to the naked eye. So spray this on your iPhone or any mobile device and it won’t look a bit different. Stephen Coulson, the chemical engineer who invented this new technology stated “You look at it and you can’t see any change. But when you drop water on it, it will just bead up and drop off. More importantly, the internals will also be protected to prevent corrosion damage”.

Interestingly, the British Ministry of Defense started the question of whether water repellent chemicals could work- specifically to protect its soldiers during attack. They wanted uniforms that could resist all types of liquids including chemical weapons. So P2i created clothes for the British Army.

Continuing with their success, P2i now works with Motorola and TCL Alcatel. But they are not only limited to electronics, recently they began working with  shoe-makers K-Swiss, Nike and Adidas. P2i is now experimenting with formula one racing cars, tennis balls and surfboards. Coulson stated “we see the future as everything being treated with P2i’s technology”. Here is a video from CNN talking with P2i about the nano-coating. What do you think of this new product?







Largest Mass Poisoning of a Population in History

Picture this familiar scene: waking up in the middle of the night, too lazy to go to kitchen, and quenching your parched mouth with water from the bathroom sink. To people in America, this is a safe undertaking. But to people in Bangladesh, it could be deadly.

Arsenic is a naturally occurring element on Earth’s crust, which can enter drinking water from natural deposits. Its effects on the human body have been known to cause respiratory, circulatory and heart problems. Recently, however, researchers have had the chance to study itseffects on humans more closely in Bangladesh because of its unusually high percentage of arsenic in its water supply. And what researchers found was eye opening.

Researchers at the University of Chicago studied more than 11,000 Bangladesh men and women. After 6.6 years, they found that residents exposed to arsenic at 19 parts per billion or less showed signs of reduced lung function. While people who were exposed to 20 parts per billion or higher had the lung capacity similar to that of a long-term smoker.

The researchers recorded 407 deaths, 198 from circulatory diseases. 35-77 million people are exposed to arsenic in Bangladesh alone.  The World Health Organization deemed the country’s arsenic contamination as “the largest mass poisoning of a population in history.”

Why should we be worried (other than the obvious ethical issues)? A group of Dartmouth researchers found that 2.3 million people in New England use wells as their main source of drinking water. This makes up approximately 40 percent of the population in Maine and New Hampshire. Although wells in the United States generally contain small amounts of arsenic, the researchers found that overtime, small doses of arsenic can lead to skin, bladder and lung cancer. So maybe next time it’s worth the trip to the kitchen.

Hartley 2, The Stork of Earth’s Water

You may remember what you were told about how water came to be on earth when you were younger.

Photo Credit: Creative Commons by AndyRobertsPhotos

Perhaps your siblings suggested that you cried so much you made the Atlantic. Perhaps that strange man your parents don’t like confided in you that water is merely a government conspiracy. Perhaps your elementary teachers assured you that you would learn about it when you were older. Well, the answer (or part of it, at least) is here. And the answer is: Comet Water.

A recent finding by researchers suggests that part of the world’s water supply may have been delivered by comets. To this day, only six comets have ever been detected with water on its surface. This new comet, named Hartley 2, was found with ice by scientists using the Herschel Space Telescope. What makes Hartley 2’s ice so profound compared to the other comets with water, has to do with their molecular composition. The other comets’ water had a ratio of deuterium to hydrogen that did not match up with the molecular composition of earth’s water. This suggests that those comets were not the source of earth’s water. Scientists believe that the ratio of these other comets did not match because they came from something called the Oort cloud. Hartley 2, is believed to have come from the Kuiper Belt which is “1,000 times closer to earth [than the Oort cloud]” This closeness seems to be the reason that Hartley 2’s ice is a molecular match for the water on earth.

With this finding, other comets can be compared to Hartley 2’s composition and determined as a match. However, with this exciting new finding also comes the promise of much more work in the future. Paul Hartogh, who works for the Max Planck Institute for Solar System Research in Germany, hints that: “This finding means that models of the formation of the solar system may have to be revisited.” 

Do you think that finding a possible source for earth’s water is worth re-thinking many current scientific knowns? Were you surprised that a comet could be a credible source of earth’s water? Don’t hesitate to comment below, I’m sure everyone would like to be updated on the research about this topic. And remember, with this new found knowledge you have to power to educate others about a true source of earth’s water.

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