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Perfect Para: Cell signal notes

Submitted by akoundinya on Thu, 09/21/2017 - 19:15

Extracellular signaling is essential to the function of cells in the human body. While transcription of DNA in the nucleus and translation into proteins in the ribosomes are essential drivers of cellular function, signals outside the cell have a major impact on cell signaling. While stimuli such as light, odors, tastes, and mechanical stress all influence cell signaling, specific proteins called Hormones are substances produced within specific cells to regulate the function of other cells in different areas of the body. Extracellular signaling usually starts by a ligand binding to a receptor on the cell membrane of a cell. When a ligand binds to a receptor and causes a biological reaction in the cell, this ligand is known as an agonist. When a ligand binds to a receptor and causes no reaction other than the binding of the receptor, it is called an antagonist. After a ligand binds to the receptor and is absorbed into the cytoplasm, the ligand receptor can now interact with the G Protein. The name G protein came from its ability to bind to guanine nucleotides. After the ligand/receptor interact with the G protein, the G protein becomes activated and starts to activate other intermediate proteins called Secondary Messengers. These secondary messengers perform a variety of functions from aiding with the transcription of certain genes to the translation of specific proteins. Secondary messengers represent the intracellular reaction to the extracellular signal.

The Caterpillar in the Cup

Submitted by akoundinya on Fri, 09/08/2017 - 15:33

The organism appears to be a worm of a white-tan color with a segmented body. It has a brown head and a curled tail. It also appears to be the larval state of some sort of flying insect such as a moth or butterfly. For movement, the worm has 3 pairs of legs under the upper torso area right below its head. These 6 legs move constantly and allow the worm's upper body segments to move around. In the middle to lower torso, the worm has 4 pairs of legs that don't move as constantly. When the worm climbed on the ruler, it became apparent that the the middle 4 pairs of legs provide a type of suctioning support that allows the worm to stick to the surface of a leaf despite gravity. The worm usually stays in a somewhat curled state, most likely as a strategy to become less visible to potential predators. However, it its fully extended state, the worm was approximately 2 cm in length. The worm has tiny hairs all along the length of its body. These hairs allow for sensory detection of the environment and allows the worm to react to stimuli that it cannot see. The worm reacts quickly to touch and becomes visibly agitated and moves away from stimuli. The worm does not have any features that look like eyes but I assume that even if it has eyes on the front of its head, the worm relies on the hairlike structures for the majority of it's enviromental awareness.  

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