In our Mediaphys Lesson I learned that the primary structure of a cell membrane is made up of a double layer of phospholipids molecules. The hydrophilic heads of the phospholipid molecules face outwards towards the water base solutions inside and outside the cell. The membrane is also made up of proteins, carbohydrate molecules, and cholesterol that form gates and pores, cell recognition, and stability. Active transport is used when a cell needs a substance to cross the membrane against its concentration gradient using protein carriers. Examples of active transport are endocytosis, exocytosis, and phagocytosis. Passive transport does not require energy it is powered by the concentration gradient of the molecule. Examples of passive transport are diffusion, facilitated diffusion, filtration, and osmosis.
In our Osmosis Lab I used a Grade a large egg from the grocery store. Its circumference is 5 ½ inches it is smooth with no cracks. I carefully place the egg in a clear plastic cup and fill the cup with vinegar. I immediately notice bubbles covering the egg and sifting upwards towards the top of the cup, looking through the cup I can see the egg is slightly suspended in the liquid. Within 25 hours there was white foam covering the egg. I cannot see the egg looking directly down. Through the cup I see the egg is still covered in bubble and is still slightly suspended. The next 48 hours there is still foam on the surface with what I can make out is pieces of the shell. Looking through the cup the egg looks larger and is not suspended in the vinegar anymore. I removed the egg and measured its circumference which was 6 ¼ inches. This change in the egg is due to passive transport called osmosis, moving from the higher water concentration in vinegar to the lower concentration in the egg. The egg is softer, the shell is gone like it had been boiled and the shell cracked off. After documenting the effects the vinegar had on the egg I placed the egg in corn syrup and let...
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