Characteristics Of A Plasma Membrane

Decent Essays
BIO181– Hybrid W4 - Membranes/Metabolism Name: Meghan Woodford

*** In all cases, answer thoroughly, and support with clear examples. (allot 4+ hrs/W)

1. Fully describe the characteristics of a plasma membrane. Be specific using your own words. (2-3 paragraphs – include structure, general function, proteins.)
Cell membranes are basically the barrier of a cell between its interior and its exterior environment. It protects the cell as well as governs what can and cannot pass through and enter into the cell. The phospholipid bilayer is a layer of lipids (or more specifically, phospholipids) packed close together that creates a barrier for the cell membrane. The membrane is also made up of proteins and cholesterol. Cholesterol is
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Active transport on the other hand is the movement from low to high concentration. This kind of transportation requires energy. An example of this would be moving those sodium chloride molecules from the diluted left side to the concentrated right side. Now looking at osmosis, this is a process that takes place after reaching equilibrium. The sodium chloride is still moving between both sides, but instead of the right side moving more quickly to the left side (in diffusion) both sides are moving between the membrane at the same rate.

3. Use crenation, red blood cell shrinking, plasmolysis, and turgid plant cells to differentiate between hypertonic, hypotonic, and isotonic. (2-3 paragraphs)
Starting with hypertonic, it’s a term used to describe when the exterior environment of a cell is more highly concentrated than its interior environment. Say you placed an animal cell, such as a red blood cell, in a solution high in sodium chloride. The water inside the red blood cell would rush out, causing the cell to shrivel up. This is called crenetion. It’s a result of osmosis where red blood cells undergo shrinkage. Something similar happens in plant cells, however, with plant cells the membrane gets teared off the cell wall. This is called plasmolysis. This happens because the cytoplasm is mostly made up of water, so as that shrinks from all the
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