AP Biology class blog for discussing current research in Biology

Author: rizhu

CRISPR gene editing: The Benefits and the risks

CRISPR gene editing is a precise technique that uses the Cas9 enzyme and gRNA to modify DNA sequences in an organism’s genome. This method is inspired by a natural bacterial mechanism that protects against viruses. It can change existing genes, introduce new genetic material, and revolutionize fields such as industry, agriculture, and medicine.

CRISPR gene editing was first invented in 1987 by Ishino Etal. Scientists first hypothesized that prokaryotic cells use this method as part of their adaptive immune systems. However, this method was not elucidated until 2007. This gene-editing technique uses RNA molecules to direct the Cas9 enzyme to the precise location where the DNA strands are being cut, thus allowing genetic materials to be modified or added. To be more specific, this system relies on the enzyme’s ability to cleave DNA double helix strands at a particular location, allowing scientists to modify the DNA sequence. This technique is especially beneficial to the medicinal fields due to its specificity; it can potentially treat genetic diseases such as cystic fibrosis, Alzheimer’s, Huntington’s, Parkinson’s, or cancer by modifying the immune cells and directing them to target and kill cancer cells.

CRISPR-Cas9 Editing of the Genome (26453307604)

Despite the benefits, CRISPR also contains some serious risks. A specific protein called p53, also known as the “guardian of the genome,” helps to detect any damage in the DNA and thus; heads the cells to stop diving to prevent any mistakes. The CRISPR technique might trigger a p53 response, in which edited cells can be “tagged” as damaged and eliminated, thus reducing the efficiency of the gene editing process. However, recent research also indicates that CRISPR can lead to cell toxicity and genome instability. In addition, CRISPR may disrupt normal cell functioning, which leads to cells being unable to detect any DNA damage or extra cell division, thus increasing the risk of further mutations.

Nonetheless, CRISPR still goes deep down into our biology field as it contains molecular biology, where it goes deep down into the cells and modifies DNA sequence. However, changing an organism’s DNA sequence using CRISPR gene-editing technology could have unintended consequences such as off-target effects, incomplete editing, and unknown long-term effects such as cancer or DNA mutation if the matching went wrong.

Cancer: What Can We Do to Treat It?

We’ve talked about many viruses before and how they affect our bodies. However, what we’re talking about today is not  a virus, but when people get it, it’s scarier than most viruses. It is called Cancer.

Breast cancer cell (2)

There are currently more than two hundred cancers around the globe, and depending on the severity of the Cancer, the treatment is also determined. Cancer, unlike a virus, is where the cells divide uncontrollably. In addition, it also tricks the cells inside our bodies into creating new blood vessels to feed the tumor cells to generate more. Our cells and blood vessels will eventually attack these cells, forming tumors. Once the tumor gets big enough, it can divide and move to different parts of your body, and if the tumor is on some vital organs, it can suppress those organs, eventually leading to death.

The current methods to treat cancers are chemotherapy, radiation, or surgery. The first two methods aim to kill tumors that are potentially growing and spreading to different parts of your body. However, if the tumor is not that big, the doctors might suggest surgery to remove the tumor located in a particular area of your body. At the end of the day, it’s about stopping the uncontrollable cell division that’s happening inside of your body.

One good piece of news is that nowadays, we have the technologies to not only give our treatments to more people who suffer from cancer, but we also can cut out the energy supply to those cancer cells.

Why don’t we have a cure to HIV?

HIV, Human Immunodeficiency Virus, is a severe virus that destroys the body’s immune system, which can later lead to AIDS(acquired immunodeficiency syndrome) if the virus is not treated. Since its discovery in 1981, there have been no proper ways to completely cure this virus, which led many people to wonder the same question: what does HIV do to our body that’s incurable?


Initially, when the virus enters the body, it uses a particular cellular protein called cyclophilin to bind with our cell receptor; it then receives our cell’s information and changes its shape to fit into the compartment. Once that’s done, HIV does a process that we often hear in biology: Receptor-Mediated Endocytosis. To further explain this, the cell is triggered by a specific ligand that matches the cell’s shape. When it’s inside the cell, HIV uses its own DNA and genes to replicate itself. After, the virus Exocytosis gets out of our cells and moves on to infect other cells in our body.

People might question why HIV is incurable? Other viruses do the same thing when entering our bodies, but they can still be cured. To answer this question, we need to go back inside the cells to see what the virus is doing there. While HIV replicates itself and infects cells, it also integrates with the host’s DNA to create reservoirs. When inactivated, the virus inside the pools are remained “silent.” However, once the current virus inside the body is used, a stimulus is sent to those reservoirs to reactivate the remaining virus and start the infection.

Despite its fatality over the years, with modern-day’s medical technology, a person with HIV can live just as long as those who are HIV-negative if the virus is detected early. With that being said, it is crucial to receive early treatments once you have HIV.

How is COVID-19 similar to Yellow Fever

Since the start of the pandemic, COVID-19 has affected millions of people around the globe. It’s an RNA virus that causes fever, cough, and death. Like other respiratory viruses, COVID-19 spreads quickly by particles that come out of your mouth when you sneeze, breathe, and cough.

Novel Coronavirus SARS-CoV-2


One similar virus is Yellow Fever. It’s also an RNA virus that transmits by mosquito bites. Depending on the person’s body, one might react differently from another. Most people either have no symptoms or mild symptoms that can be recovered in a week. However, people with weak immune systems might develop severe symptoms such as high fever, chills, and body aches. In addition, the fatality rate for people to develop severe symptoms is between 30%-60%.


Now you might wonder, what makes those viruses similar? Aside from them being RNA viruses, they also have similarities in symptoms. Still, most importantly, those two viruses both do something that I mentioned in my last post: Endocytosis. When these viruses enter our body, they use their special protein receptors to trick our cells into thinking it’s some proteins that benefit our body. Once viruses enter the body, using receptor-mediated cytosis, it uses its own protein and DNA to replicate themselves, including those false proteins. One thing to note is that those viruses can’t replicate by themselves. They would need to rely on living cells to multiply. Once the viruses replicate themselves, they carry on with exocytosis to exit the infected cell and infect more cells in our body.

Last but not least, Yellow Fever and COVID-19 can’t be completely cured since the viruses mutate so quickly that we don’t have enough time to find what can erase those viruses completely. However, as long as we receive vaccines and take care of our health, those viruses shouldn’t worry us too much.


What is Marburg Virus and why is it so fatal?

Many people probably never heard the term “Marburg Virus” before. Still, it is one of the deadliest viruses humans have ever found, with an average fatality rate of 50%, ranging between 23% to 90%, and there’s still no approved treatment to cure this virus. So what is Marburg Virus, and what does it do to the immune system that causes us to be in danger? To understand all of these, we must first dive into the structure of the Marburg Virus and what “strategies” they use to deceive our immune system and enter our cells.

According to CDC, Marburg is a virus that originated in 1967 in Marburg and Frankfurt, Germany, and in Belgrade, Yugoslavia (now Serbia). It is a virus that attacks your immune system to cause severe fever, Malaise, and diarrhea. In addition to those symptoms, people who get the virus can also suffer severe weight loss, vomit, and even organ failure. The virus was not very active for the past 20 years, but recently, in August 2021, a 46-year-old man from Temessadou M’Boké, a village in Guéckédou prefecture in Guinea, died after hemorrhaging from several natural orifices. Marburg virus

To understand this virus, we must first look at its structure. Marburg Virus(MVD) is an RNA virus that can enter our cells by endocytosis, specifically receptor-mediated endocytosis. Since Marburg Virus is a special type of virus, it has its own attachment proteins; it uses the process of Receptor-Mediated Endocytosis because it triggers a specific receptor in a coated pit. After the virus triggers the receptor on our cell, it gets attached to our cell surface and clusters the receptors. Because Marburg Virus also contains its own protein, our immune system falsely identifies it as something good for our body, which allows them to attach to our membrane and send the virus into our cells. Once it’s in, the virus uses its RNA to provide information to replicate and infect cells using viral proteins. Once a cell is infected by the virus, the virus and its copy use the same process to infect other cells in our body until the majority of our cells are infected. (SARS-CoV-2 uses the same process as Marburg Virus since they both are RNA viruses.)


Now that we know the structure of the virus and how it enters our body, we need to figure out why it is so deadly. We certainly have many RNA viruses that exist in our daily lives, but most of them are not fatal. One of the differences between Marburg and other viruses is that it can cause severe hemorrhagic fever, similar to the symptoms of Ebola. It is a condition that affects many body organ systems, damages the overall cardiovascular system, and reduces the body’s ability to function. Furthermore, the fever will reduce the level of blood-clotting cells in our body, leading to severe internal bleeding and death as the excess amount of blood pressures your organs and tissues.

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