Posted by cweig001 on Dec 8, 2025 in Posts
I never thought cell biology was particularly relevant to me. My formal education is in conservation biology and ecology, and so the cellular level never seemed super interesting to me. I taught general biology labs for almost three years, which made the information quite accessible to me, since I used to teach most of it. For example, cellular respiration, photosynthesis, and cell division were all topics I used to actually teach, and now I got to learn about them again more formally. When I taught them, I thought I knew everything about them. After (and during) taking this course, I quickly learned that there are always more details to most subjects in biology. For example, even though I taught photosynthesis, we dove into much more detail in this course than when I taught it, since we learned every specific substrate of the Kreb’s Cycle and the associated enzyme with each step. This semester I also took anatomy and physiology with lab, and so there was significant overlap with that course. We learned all different types of cells in A&P, which mirrored what I learned in this class. In fact, sometimes I found it hard to remember which content belonged to which class. However, A&P focused more on the function of the cells, which helped me apply the details I learned in this cell biology course to the broader organism. For example, we just learned about gap junctions, which are crucial to the functioning of cells that need to communicate rapidly. In my A&P class, we learned about muscle cells and how a power stroke is formed, which starts with the uptake of calcium ions into the muscle fibers and is facilitated by gap...
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Posted by cweig001 on Dec 8, 2025 in Posts, Uncategorized
Background Intestinal plasticity is an adaptation in animals that allows them to shut down their intestine in order to conserve energy. Only certain animals have this adaptation, and the adaptation is usually seen in animals that go long periods without eating, such as most snakes. Unlike mammals or birds that feed daily due to their fast metabolisms, snakes often fast for long periods of time. When they do eat, they often have to digest a food source that can be larger than half of their own body weight. To make their metabolism more efficient, snakes have developed intestinal plasticity which allows snakes to essentially turn off their intestine. For example, during fasting, the tissues in the intestine will shrink and the enzymes will also decrease, resulting in overall energy usage (Andrew, 2015). After feeding, the opposite occurs and there is a dramatic transformation. New cells are formed, digestive enzymes rise, and nutrient absorption increase. This rapid remodeling is what biologists call intestinal plasticity, and it allows snakes to be extremely efficient at maximizing their energy by only using it when necessary. This adaptation is often seen in sit-and-wait predators, such as the Burmese Python. Plasticity is a common theme in life, and is not limited to digestion. In vertebrates, maintaining proper levels of calcium and phosphorus in the body is equally important and requires precise hormonal control. Calcium, for instance, is essential for bone strength, but it is also critical for nerve impulses and muscle contractions. The parathyroid glands secrete parathyroid hormone (PTH) when calcium/phosphorous levels drop. PTH acts on bones, kidneys, and the intestine (through vitamin D activation) to bring calcium back into balance (Bringhurst et al., 2018). Inversely, calcitonin is a hormone produced by the thyroid gland that reduces blood calcium levels. When calcium levels rise too high, calcitonin helps by preventing bones from releasing calcium and encouraging calcium storage in bone tissue. In short, PTH increases blood calcium levels while calcitonin decreases blood calcium levels, and together they maintain homeostasis (Carter, 2006). For both intestinal plasticity and the homeostasis of elements such as calcium and phosphorous, biologists rely on advanced tools to visualize the microscopic cells involved. Electron microscopy is one tool, which works by shooting beams of electrons at a specimen, which allows biologists to achieve magnifications far beyond traditional microscopes (because electrons are smaller than wave of light used in light microscopes). Transmission electron microscopy (TEM) reveals the inner structure of cells, allowing biologists to see a detailed shape of the specimen. Another type is scanning electron microscopy (SEM), which provides sharp, three-dimensional image of the surface of a specimen. These methods have been invaluable to biology on their own, but in combination with new technologies, we have been able to learn even more about our world. For example, electron microscopy can be combined with Energy-Dispersive X-ray (EDX) analysis. EDX identifies which elements are...
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Posted by cweig001 on Oct 30, 2025 in Posts, Uncategorized
I made this meme because I think its funny how inefficient photosynthesis is. It takes six turns of the Calvin cycle to create one glucose, making it a very inefficient process. Despite this, chloroplasts are the basis for nearly all life we have here on Earth. If we could make photosynthesis more efficient, it makes me wonder how much more abundant life would...
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Posted by cweig001 on Sep 13, 2025 in Posts, Uncategorized
I drew a polypeptide that contains two amino acids: Methionine and Alanine. Methinoine is always the first amino acid in all polypeptides, except in bacteria, where it is still a Methionine but is slightly modified...
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Posted by cweig001 on Sep 11, 2025 in Posts, Uncategorized
In my time as an undergraduate, I worked in a lab with an advisor who studied the North American Porcupine (Erethizon dorsatum). I mostly looked into their ecology and focused on their preferred habitat and main predators. Most people know porcupines for their quills, which are made of keratinized cells. These cells have most of the organelles of a normal animal cell when they are in the basal layer of the epidermis (see drawing below). Ribosomes are especially important for their later role in the production of keratin. However, as these cells move through the epidermal layers, they lose some of their organelles, such as the nucleus, rough endoplasmic reticulum, and the golgi...
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