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Biology Questions
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Biology Questions
Question 1
A person can be exposed to methyl isocyanate through inhalation, skin contact, eyes, or ingestion. Irritation in the skin, eyes, and respiratory tract are common when an individual is exposed to methyl isocyanate. Acute exposure to large concentrations of methyl isocyanate may cause the development of severe pulmonary edema and injury to the alveoli. Additionally, the toxin can severely damage the cornea of the eye and can lead to death. People who survive from toxin exposure develop long-term effects such as respiratory and ocular difficulties. A pregnant woman exposed to methyl isocyanate may have miscarriages, fetal death, or spontaneous abortions. The effects can persist for years especially, the reproductive and ocular effects (Limaye).
The mechanisms of isocyanate reactivity are poorly understood. However, it is postulated that when someone is exposed, the toxin supplements the production of the mitochondrial reactive oxygen species, hastens the depletion of enzymes that antagonize ROS, and causes an increase in the actions of pro-inflammatory cytokine. The toxin then induces apoptosis by jeopardizing the balance of the mitochondrial-nuclear cross talk. Another assumption is that the toxin carbamylated globin and blood proteins.
Methyl isocyanate causes pulmonary edema, electrolyte imbalance, and bronchospasm (Limaye). Other adverse effects include skin irritation, ocular damages, gastrointestinal effects such as nausea, vomiting, abdominal soreness, and irritation of the respiratory tract, causing compromises in the lung tissue. Also, the damaged lung tissue can easily be infected by bacterial cases of pneumonia. Skin irritations may be manifested as chemical burns when one is exposed to high concentrations of the gas.
Question 2
The extracellular matrix is composed of proteins and polysaccharide elements. ECM can either exist as the basement membrane or as an interstitial matrix. Extracellular matrix offers physical support to the cell and enhances signaling regulations. EMC might offer a fibril-like environment to the cells or a sheet-like membrane of the epithelial cells’ basement. The extracellular matrix supports developing tissues by enhancing cell adhesion, movement, shape, and cell differentiation. The ECM offers anchorage to the cell via the cell adhesion molecules such as the integrin. Additionally, the ECM is essential during embryonic developmental stages, such as during the separation of embryonic layers. Cells are sensitive to the mechanical triggers generated from the ECM. Cells respond to stimuli arising from the microenvironment. Such stimuli include changes in the ECM topography, toughness, and structure. Such signals are transformed into cellular responses through a process known as mechanotransduction.
The ECM acts as the microenvironment for cancer cells. If greatly heterogeneous and is made of cells such as fibroblasts, endothelial cells, and fibroblasts. The non-cellular elements include the proteins and polysaccharides. The extracellular matrix offers a biochemical and biomechanical structure in which tumor cells are found. The ECM offers a barrier through which cancer cells must traverse to get into the bloodstream to allow cancer progression. Signaling between cancer cells and the ECM is crucial for tumor growth. Tumor cells can readily alter their physiological traits to enable them to thrive in unfavorable environments. Researchers believe that the ECM can induce cancer cell plasticity. Besides, high deposition of ECM components such as facilitates the stiffness of tumor cells. The collagen fibers aid the growth of cancer cells as well as migration and formation of metastasis. Hyaluronan and POSTN, ECM components, are essential in the metastatic niche. POSTN also facilitates the maintenance of cancer stem cells by augmenting the WNT signaling pathway. Hyaluronan receptor supports disseminated cancer tumor cells during metastasis. Studies show that cancer cells produce significant amounts of ECM to aid in disease progression (Holle et al.).
Drugs could be designed that target the interaction between the cancer cells and the extracellular matrix. However, there have not been many drug discoveries that target the signaling between tumor cells and the extracellular matrix. Drugs targeting the integrin or collagen could be useful in inhibiting metastasis. Designing drugs that target particular integrin interactions focus on inhibiting protective downstream signaling influences convened by the specific receptors. ATN-161 is a drug developed to target fibronectin. It non-competitively inhibits fibronectin PHSRN sequence. The drug is exceptional; it does not inhibit integrin-dependent adhesion; instead, it inhibits downstream signaling through alpha5beta1 and alphavbeta3 integrin. The drug has anti-angiogenic and ant-pro-survival properties, which are important in inhibiting cancer cells’ proliferation (Holle et al.).
Question 3
Cyclins and cyclin-dependent kinases are the two positive regulator molecules that ensure the cell cycle’s progression through various checkpoints. The levels of cyclin molecules are affected by internal and external triggers. Their concentrations vary in different phases of the cell cycle. To be effective, cyclins bind to Cdks, and the complex undergoes phosphorylation. Phosphorylation is important in activating the complex—the phosphorylated complex the advances the cell cycle.
Works cited
Holle, Andrew W., Jennifer L. Young, and Joachim P. Spatz. “In vitro cancer cell–ECM interactions inform in vivo cancer treatment.” Advanced drug delivery reviews 97 (2016): 270-279. https://doi.org/10.1016/j.addr.2015.10.007
Limaye, P. “Methyl Isocyanate.” (2014): 306-309. https://www.sciencedirect.com/topics/chemistry/methyl-isocyanate