bioljordy – BioQuakes

The Biology of Skin Color

On March 7, 2021

It’s a hot summer day and you are relaxing by the pool. Ever wonder why your skin gets darker or tanner when doing so? It’s because of melanin!

Melanin is a skin pigment that can be found in humans, animals, and most organisms. It is responsible for making hair, skin, and eyes appear darker. Melanin exists in two forms: eumelanin and pheomelanin. Eumelanin is black or brown pigment and pheomelanin is red or yellow pigment in one’s skin tone.

Different Skin Colors

When you are exposed to the sun, more melanin is produced. “In human skin, melanin pigments are synthesized in organelles called melanosomes that are found in specialized cells called melanocytes in the skin epidermis.” In order for melanocytes to produce melanin, a receptor protein called MC1R, found in the melanocyte cell membrane must be activated by melanocyte-stimulating hormone (MSH) which is secreted by the pituitary gland in response to exposure from UV light. Once MC1R is activated, it triggers the production of release of cAMP and as we learned in class, this triggers a cell signaling pathway ending with the release of eumelanin, making our skin appear darker.

A short additional fact is that melanin protects us from skin cancer. Melanin can absorb the UV rays and block them from reaching and damaging the DNA within one’s melanocytes. In this case, melanin acts as “a protective agent in the skin” joining your first line of defense to protect you against pathogens or in this case to protect you against the damaging UV rays. There are three types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and melanoma.

A person’s skin color depends on the amount and type of melanin (eumelanin or pheomelanin) present in one’s skin. Genetically speaking, “people with naturally darkly pigmented skin have melanosomes that are large and filled with eumelanin” (biointeractive.org). As discussed above, there is a huge biological importance of melanin; without it, humans wouldn’t have a protective skin barrier against the UV rays emitted by the earth, but throughout history the importance of melanin has been placed to the side due to the idea of race or more specially racial superiority based on ones skin tone being introduced into the conversation.

In short, while there is a biological basis of skin color, there is no biological basis or scientific explanation of race. Although it has been attempted, by Samuel Morton in the 1800s when he compared the brain sizes of the five racial groups or by Dr. Menegele during WWII when he measured facial features of the Jewish people, it is challenging to use science to support the concept of race. In fact, there are more differences within the “determined” races (African, European, Asian, Oceania, Native American) than between them! No specific amount of melanin, or any trademark alleles for that matter, specify a race. It is important to look at and understand science and evolution- looking at where people come from and why they have that skin color that they do based on melanin and weather conditions around them. It is important to take into account how we have evolved into unique humans, even though 99.6 – 99.8% of our genetic material is identical. It is important to educate ourselves about why we are the way we are and how evolution has impacted that, not how groups of people throughout history have tried to give an racist explanation for it.

Skin Colors Found Around the World

So we beat SARS and MERS… Why haven’t we beat COVID-19?

By bioljordy

On December 15, 2020

In Student Post

Many people, especially those who were alive during the SARS and MERS outbreak, may be wondering why we haven’t beat the Coronavirus yet if we beat the SARS and MERS outbreaks, two very similar viruses to COVID-19 or Sars-CoV2. This is a question many people have been facing everyday as the Coronavirus disease has caused a shift in the entire globe’s day to day life unlike SARS and MERS.

SARS, MERS, and COVID-19 are all part of the coronavirus family. “Coronaviruses are a large family of enveloped RNA viruses” that can be found in a variety of bat and bird species. While this makes the three viruses similar, they all have specific differences causing unique results in terms of outbreaks and how the specific viruses have spread. What is so powerful or different about the coronavirus causing COVID?

First of all, let’s talk about how viruses hijack our bodies. Viruses are microscopic parasites, much smaller than bacteria, that contain key elements that make up all living things such as nucleic acids and DNA or RNA, but are unable to replicate and access this information encoded in their nucleic acids, meaning they cannot self replicate. In order to reproduce, they rely on the genetic material of host cells (our own cells). As we talked about in class, viruses are able to bind to our cell surface receptors and trick our cells to “let them in”. The viruses are then able to hijack our cells by releasing their genomes, or that information they couldn’t previously access, resulting in our cell making millions of copies of that genome to spread throughout the body in order to infect other cells and / or other human hosts. This is how all three of the coronaviruses hijacked our bodies and communities. Let’s hear what happened once this step occured.

SARS stands for Severe Acute Respiratory Syndrome. The SARS outbreak began in the Guangdong province in China in 2002. The coronavirus that caused SARS, called SARS-CoV, was likely spread to humans, in the China wet markets, from civets or other animals who acquired the virus from horseshoe bats. The World Health Organization (WHO) issued a global alert after identifying an atypical pneumonia spreading amongst hospital staff and later names the virus SARS based on the symptoms people began to express. The epidemic was controlled on July 5th 2003 and only four cases have been reported since, 3 of which being in a lab setting dealing with the specific coronavirus. The reason why SARS was able to be contained so quickly was due to the fact that one could only spread the virus if he/she had symptoms and if one expressed symptoms it was easy to self isolate, therefore not spreading the virus to others. In addition, SARS has a fatality rate of 9.6% meaning a good number of people who contracted SARS were likely to pass on and therefore not pass on the virus to others.

MERS stands for Middle Eastern Respiratory Syndrome. As we learned in class, viruses are no longer named by their place of origin, but this was not the case in 2012 during the outbreak of MERS. Similar to SARS, MERS is a zoonotic virus, meaning MERS was passed from an animal, in this case a camel who contracted the virus from bat once again, to humans in Saudi Arabia. Although 27 countries have reported cases of MERS since 2012, transmission among people is rare and MERS has a fatality rate of 34.3%, making it even more deadly than SARS and therefore making it even harder to spread.

The first case of COVID-19 or SARS-CoV-2 was reported in Wuhan China in December 2019. By the end of January 2020 the WHO had declared a public health emergency of international concern and by the beginning of February the WHO had declared a pandemic. So what makes the coronavirus disease so much worse than the other ones? How did COVID-19 spread so quickly and to the entire globe? And why are our daily lives changed forever or at least until we can get a handle on the virus?

Origin of the three coronaviruses

First of all, the COVID-19 causing coronavirus SARS-CoV-2 is very similar to SARS-CoV, but with very unique and important differences. What we have all learned about SARS-CoV-2 is that you don’t need to be experiencing symptoms to transmit the virus. This is very different from SARS-CoV where you needed to have symptoms in order to transmit the virus. Also, while the transmission rates are lower for MERS and SARS because the fatality rates are higher, in the case of COVID-19, the fatality rate is approximately 1-3%, meaning more people are surviving COVID-19 making it easier for this virus to survive and pass on to other people that it has yet to infect. In addition, as we talked about in class, we have evidence that “viruses can naturally mutate to mimic host biology so as to ensure successful viral propagation” and as a result “a host of high frequency mutations have resulted in a least 5 differentiated SARS-CoV-2 strains to date” making it even harder to develop a successful vaccine to target and eliminate the coronavirus disease.

So, will we ever be able to put a stop to the spread of the coronavirus disease and therefore the pandemic? The answer is yes, but we first need to figure out how to stop the spread of the virus. The truth about COVID-19 is that unfortunately, as stated above, it is much easier to transmit than SARS and MERS, and COVID-19 has been able to get on planes and travel the world unlike the previous coronaviruses. While it is easier to transmit it is also more survivable than the other coronaviruses that have impacted our communities thus far.

Exercising in the “Extremes” (Hot or Cold) Does Not Necessarily Lead to Weight Loss. Here’s What Does:

By bioljordy

On October 15, 2020

In Student Post

As it has been a trend for years, many believe the claim that exercising in cold or hot temperatures will cause you to burn more calories, leading to weight loss. Although many believe this, it is not actually true nor an efficient way to lose weight.

First, let me take you through how humans burn calories. The most common way you burn calories is by your metabolism. According to the Mayo Clinic, “metabolism is the process by which your body converts what you eat and drink into energy. During this complex biochemical process, calories in food and beverages are combined with oxygen to release the energy your body needs to function.” Metabolism can also be classified as your basal metabolic rate, or how many calories your body uses to carry out these functions. The basal metabolic rate makes up about 60 to 80 percent of your total energy expenditure and calorie loss. In addition to your metabolism, a portion of your energy expenditure and therefore loss in calories comes from thermogenesis: the way in which the body produces heat. Thermogenesis makes up 10% of total energy expenditure, leaving only 10-30% for physical activity (which, in reality, is not a lot).

In terms of that last 10-30%, the body burns the remaining calories by shivering (if cold) or by exercising. Shivering and exercise are viewed as the same inside of the body as they both trigger the activation of what is called brown fat or brown adipose tissue. When you shiver, your muscles involuntarily contract to generate warmth to regulate homeostasis but it also triggers “muscles to secrete a hormone that stimulates energy use in brown fat cells” (according to the National Institute of Health). The same thing happens when you exercise! In another example, brown fat helps infants who don’t know how to shiver yet regulate their body temperature.

While brown fat burns calories to generate heat, something called white fat stores calories as heat / insulation to keep you warm. As you can assume, It is better to have more brown fat than white fat as large amounts of white fat, and this insulation, can lead to obesity. This is because white fat stores energy in large lipid droplets throughout the body. On the other hand, brown fat contains smaller lipid droplets and higher amounts of mitochondria. This increase in mitochondria causes an increase in ATP or energy production and therefore increase in energy expenditure and calorie loss.

Exercising Outside (in the cold or heat)

So how is this related to energy expenditure and calorie burning, you ask? Many people believe that you can burn more calories in the cold because of this brown fat. Although this is true, you need at least 2 hours in 66 degrees fahrenheit (or lower temperature) in order to see the extreme effects of the body activating the brown fat and burning more calories. On the other hand, many believe that you will burn more calories in the heat (or hot conditions) because sweating more must mean your body is working harder and losing more calories, right? This is not always the case – releasing more sweat doesn’t always mean you are releasing more energy and losing more calories. Rather, in the case of very hot conditions, like hot yoga for example, the sweat you are releasing only causes you to lose more water, not calories.

There are pros and cons to any type of exercise, but ultimately choosing to work out in hot or cold conditions to promote weight loss, may do more harm for you than good, especially if you are new to the exercise scene as your body may not react well to these temperatures. To promote weight loss, you must be in a calorie deficit – burning more calories than you are in consuming. This is the best and really the only way to lose weight (along with exercise).

BioQuakes

AP Biology class blog for discussing current research in Biology

Author: bioljordy

The Biology of Skin Color

So we beat SARS and MERS… Why haven’t we beat COVID-19?

Exercising in the “Extremes” (Hot or Cold) Does Not Necessarily Lead to Weight Loss. Here’s What Does:

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