AP Biology class blog for discussing current research in Biology

Author: fertilivization

CRISP[ie]R Corn Kernels?

Corn is unique in the way that its genome is highly complex, thus causing it to be very difficult to edit those genes with technology such as CRISPR. CRISPR is an advanced technology that is used to find a specific portion of DNA in a cell and then it alters that piece of DNA. To learn more about CRISPR, click here.

CRISPR CAS9 technology

In a recent study at Cold Spring Harbor Laboratory, researchers attempted to modify the growth of stem cells and promotor regions in corn using CRISPR. Thousands of years ago, corn was just a plant covered in weeds that formed very few kernels on its surface. Through gene editing technologies, scientists were able to transform the hopeless plant into a delicious vegetable with juicer kernels bursting from all surfaces. To increase the number of corn kernels 0n the surface of the plant, Professor David Jackson along with Lei Liu worked in collaboration with Professor Madelaine Bartlett from the University of Massachusetts Amherst. They were one of the first groups to tackle the editing of corn’s complex set of DNA.

Zea mays 'Ottofile giallo Tortonese' MHNT.BOT.2015.34.1

We are currently learning in AP Biology how DNA is replicated and can be altered. In replication, DNA is first untwisted by a helicase enzyme. Similarly, CRISPR uses an enzyme called Cas9 that unzips the DNA. This allows for the newly created strand of RNA to be matched to the target DNA. The Cas9 then cuts the DNA strand which causes the cell to attempt and put the strand back together and this results in new genes being formed because the DNA sequence is altered. This is just like how in replication, the DNA polymerase adds nucleotides to an existing strand of DNA. This video also provides a great visual description of how CRISPR can edit existing genes.

Since corn is a plant, it consists of plant cells that have a much stronger cell wall than animal cells do. This makes it harder for the CRISPR to access the cell’s DNA and make edits. CRISPR can be used to disrupt genes and eliminate them, as well as help the promoter regions which activate the genes instead. Corn kernel development depends on the genes supporting stem cell growth. They experimented by targeting random areas of the promoter to see which part will change the number of kernels on the cob.

Ontario-Corn-field 03

As a veggie-lover myself, I am so glad that these new gene-editing procedures allow for fuller, juicier corn kernels. Not only is this beneficial to those who eat corn on the cob or choose to enjoy a moist slice of cornbread, but also to those who love to sit down with a big bowl of popcorn to watch a movie. If a vegetable with such complex genes as corn is able to be improved, imagine what the future holds for other plants yielding yummy additions to our diets!

Sea Cucumbers Soon to be Vegetables?

A recent article has established that our sea cucumber population is in great danger. The main cause of the newly endangered species is the high demand for sea cucumbers in East and Southeast Asia. The Great Barrier Reef is home to thousands of unique species, tropical sea cucumbers being one of the many. Sea cucumbers are often believed to just “exist” and not have any purpose, but they are in fact vital to the underwater ecosystem.

Coral Outcrop Flynn Reef

Well, what is their purpose? Sea cucumbers are classified as deposit feeders which means they play a vital role in nutrient cycling in the ocean. They enhance and benefit the habitat of many underwater animals that live near the ocean floor. They redistribute surface sediment and secrete inorganic nitrogen and phosphorus. These processes prevent the ocean from becoming overly acidic which keeps the coral reefs healthy. In recent years coral reefs have been rapidly dying, and without help from sea cucumbers, our earth’s coral reefs may be in even greater danger. For more information on the benefit of sea cucumbers, click here.

Dr. Kenny Wolfe from The University of Queensland led a research team to collect data from Australia’s primary sea cucumber fishing ground and they concluded that the area was in desperate need of change. Out of the 16 species of endangered species of sea cucumbers in the world, 10 of them live in Australia’s Great Barrier Reef. Since sea cucumbers are viewed as a delicacy, they are being overharvested, not allowing them to fulfill their duties of keeping the seafloor clean. Particularly, the white and black teatfish are in the most danger, due to their high market value and low reproduction rate. Though this has been established, they are still being harvested and exported. Luckily in December of 2021, it was ruled that the harvest of black teatfish would no longer be permitted. Though this is progress, what will happen to the other 9 endangered species of sea cucumbers in the Great Barrier Reef?


Since the Great Barrier Reef’s sea cucumber fishery has been running under a non-regulatory performance regulatory system, regular assessments of sea cucumber stock were supposed to take place, but they did not. This left the industry operating without any indicator of how their harvest is actually impacting stock sustainability.

In AP Biology this year, we learned about how living organisms create energy in the form of ATP through cellular respiration.  In underwater animals in general, it may be hard to imagine how they can obtain oxygen to begin this process. Sea animals get their oxygen from the water around them (H2O). Sea cucumbers are actually very unique in the way that they ingest oxygen. Most underwater animals take in oxygen through their gills, but sea cucumbers actually inhale oxygen through their anus!

Holothuria cf arguinensis

Sea cucumbers undergo cellular respiration by taking O2 from H2O and glucose and converting it to ATP energy with waste products of CO2 and H2O. They get glucose through the food they eat at the seafloor, such as algae and waste particles. The sea cucumber initially takes water in through the anus and cloaca, then the water is pushed to the respiratory trees where gas exchange is completed. This process repeats over and over to keep the sea cucumber alive.

This summer I went scuba diving in Hawaii and got to see and touch a living sea cucumber first hand.  I was amazed at the complexity of his animal that appeared to be so simple on the outside. Something that you would normally expect to act as a plain cucumber (the vegetable) on the seafloor, actually has a great impact on the environment surrounding it. We have to make sure that we do everything in our power to protect this beautiful and adorable species!

Can a Plant Based Diet Protect You from Covid?

The Covid-19 pandemic has affected and devastated millions of people all over the world over the past two years. Even after religiously wearing masks and more than half of the world’s population getting vaccinated, we still need to live in caution of getting infected with this virus every day. Although Covid-19 is known to be one of the most contagious viruses to exist, it has been discovered in a recent article that maintaining a healthier lifestyle and diet will decrease your chances of getting infected as well as minimize any symptoms if you do happen to get infected. We all know that overall if you are able to maintain healthy habits, your immune system will be stronger and therefore, able to fight off infection more effortlessly, but applying this same idea to Covid-19 may help us escape this pandemic sooner than expected. 

Since data on this theory was lacking, Dr. Jordi Merino and his colleagues conducted an experiment to gather more evidence. 592,571 participants were selected and began by completing a questionnaire assessing their dietary habits before the pandemic. Participants who had healthy eating habits had a 9% lower chance of contracting the virus and a 41% lower chance of developing severe Covid-19. Merino concluded that in addition to wearing masks and getting vaccinated, we should all try to maintain healthy, plant-based diets to fight against Covid.

Healthy non-sugar diet

In addition to the health benefits of having a plant-based diet, it improves your immune system because of the antioxidants, vitamins, minerals, and phytochemicals found in plants. These components work to keep your cells healthy and working at their fullest potential to fight off infection. They resolve inflammation in the body by neutralizing toxins, processed foods, bacteria, and viruses. With all the benefits, why wouldn’t you go plant-based?

It may sound pretty simple: if I go plant-based and I won’t get sick, right? Not exactly. It is found that the risk of  Covid-19 is greater in areas of high socioeconomic deprivation. This is because the people who inhabit these areas are unable to maintain the same lifestyle as people who are more fortunate. Plant-based diets and healthier lifestyles are generally more costly, causing them to be less accessible to everyone. This is one of the main reasons that Covid is still a great risk to our society. For more information about a plant-based diet decreasing Covid risks, click here.

In AP Biology we learned how your immune system works to fight against any invading viruses in your body. When you are contracting a virus, the pathogen first needs to pass through your barrier defenses. These are the natural defenses with which you are born. For example, they include mucus, skin, stomach acidity, blood and lymph proteins, etc.. If you are an unhealthy person and these defenses aren’t working properly, you are much more susceptible to disease and then need to rely on your internal defenses.

Primary immune response 1

This diagram shows how the humoral and cell-mediated responses work in the body to fight off disease.  When a pathogen enters the body, your immune system will attack either the pathogen itself when loose in your bloodstream and bone marrow or attack and kill an entire infected cell. Keeping your immune system strong by eating right and frequent exercise will also ensure that these defenses will fight off disease quickly and form antibodies to prevent future reinfection. A healthy person is by no means immune to a virus, but they will experience fewer symptoms as well as recover faster because their immune system works faster. This means that fewer cells will become infected and the virus will have less time to replicate and multiply.

As someone who runs track and cross country, it is very important to me to keep my diet as healthy as possible. Though a plant-based diet doesn’t suit my lifestyle best, I do make healthy food choices as often as I can to properly fuel myself and to ensure I don’t get sick. This seems to be working well for me as I am still yet to get infected with Covid-19 or show any symptoms.

Have There Ever Been Oceans on Earth’s Sister Planet?

Venus, commonly referred to as the volcanic planet, also known as Earth’s sister planet, is the second closest planet to the sun. The planet’s surface is currently known to be the hottest in the solar system due to its dense atmosphere which traps in an immense amount of heat. This characteristic of Venus is actually very similar to how Earth’s greenhouse effect traps in warm air, keeping our planet warm; however, Earth also has oceans that cool the atmosphere, thus allowing for life to flourish.  Recently, research has been conducted to get to the bottom of whether or not Venus has actually ever had oceans.

Venus dome 3D

From a distance, Earth and Venus are strikingly similar: both around the same size, with a rocky surface and an atmosphere. As mentioned previously, Venus’ atmosphere traps in far more heat than Earth’s. In addition to having a very thick CO2 atmosphere, Venus also has sulphuric acid clouds which Earth does not. Life simply cannot exist on Venus due to the intense atmospheric pressure and the extreme temperatures created by the trapped heat. An article by Charles Q. Choi and Chelsea Gohd entitled “Venus: The hot, hellish & volcanic planet” gives more information about the nature of Venus’s surface. Choi and Gohd stated that Venus has the heaviest atmosphere out of all the planets in the solar system which causes its pressure to be about 90 times that on Earth. They mentioned a similar study also exploring the possibility of oceans on Venus. It concludes that the ultraviolet radiation, from the sun, as it grew closer, caused the water vapor molecules in the atmosphere to split apart, thus allowing for the hydrogen molecules to escape into space. This was the cause of the build-up of CO2 in the atmosphere that then lead to the current-day conditions of the planet. Unlike Earth, Venus has very strong winds and is primarily a dry desert land with many active volcanoes. Contrastingly, Earth’s surface is 70% water and is covered with dirt and plants. We can understand the similarities between Earth and Venus when we dig underneath all that dirt and ocean. Earth happens to have the same rocky surface that Venus has that came from cooled lava billions of years ago. To learn more about Earth’s surface, click here.

Venus Earth Comparison Horizontal

Theories have formed that Venus was once a far more inviting planet with potential for life. The National Centre of Competence in Research (NCCR) PlanetS and the University of Geneva (UNIGE), leading a team of astrophysicists, thoroughly explored whether Venus could have actually experienced milder days. Unfortunately, according to the results of the study posted in the journal Nature, this was not the case. Martin Turbet and his team of astrophysicists used the tools available on Earth to come to a conclusion.  They created a three-dimensional simulation of both Earth and Venus in their early stages when their surfaces were still molten and any present-day water would have been vaporized. They used the simulation to then evaluate how the evolution of the plants would play out. By examining how the atmospheres evolved, they can determine whether or not it was possible for oceans to have formed in the process. Marcus Turbet concluded that “Thanks to our simulations, we were able to show that the climatic conditions did not allow water vapour to condense in the atmosphere of Venus.” Due to the level of heat in the planet’s atmosphere, the water vapor was never able to cool to the point where it would form water droplets and fall to the surface; therefore; it remained in the gaseous state and never formed oceans.

As we learned in AP Biology this year, water (H2O) plays a huge role in life on Earth and it makes sense that other planets, such as Venus, that lack liquid water, would not be able to support life. We discussed that one of water’s main properties moderating temperature. Due to water’s unusually high specific heat,  its temperature changes less when it loses or absorbs a certain amount of heat. Life can exist on Earth because Earth’s oceans are able to moderate and control any temperature fluctuations that happen on land to keep the atmosphere in ideal condition for life. Water also has a high heat of vaporization which, again, aids life on Earth. Oceans absorb heat, and as some water evaporates, it condenses and then falls back to Earth in the form of rain, thus cooling the surface. On a much smaller scale, this can be related to how humans sweat (sweat representing the oceans and humans representing a planet). I run a lot, which means that I also sweat a lot, especially in the summertime when the temperature starts to rise. The sweat being 99% water means that it offers the same cooling effects that pure water does. The liquid on the surface of my skin allows my body temperature to be lowered so I can still feel cool enough to continue on my run. Hopefully, this aids our understanding of how oceans could never have existed on Venus because the water vapor was unable to become cool enough to transform into its liquid state and moderate the temperature of the planet. Venus’s surface is left to be rocky and full of volcanoes while Earth’s surface is able to support an immense amount of life.

Powered by WordPress & Theme by Anders Norén

Skip to toolbar