Bios 1300 Exam 2| Latest Questions And Answers

BIOS 1300 Exam 2| LATEST QUESTIONS AND ANSWERS All organisms are composed of what? - Cells Why is there an upper limit on cell size? - Cells lose their ability to support themselves What does the plasma membrane divide? - The fluid within a cell; intracellular fluid from extracellular fluid What is a phospholipid? - Amphipathic molecules arranged in a bilayer Where do the phosphate heads face? - Face water on either side of the membrane Where do the tails face and what kind of tail is it? - Are in the center; hydrophobic What percent of the membrane are lipids? - 75% What does cholesterol increase? - Membrane integrity What percent is cholesterol? - 20% What percent is gycolipids? - 5% Where do gycolipids face? - Face the extracellular How much of the membrane molecules are comprised of proteins? - Comprise a small amount, but half its weight What do integral proteins do? - Penetrate the membrane depending on which portion of the protein is hydrophilic & hydrophobic Does a transmembrane protein pass completely through the membrane? - Yes What are bound to glycoproteins? - Carbohydrates What do the peripheral proteins adhere to? - Adhere to one face of the membrane What are the peripheral proteins bound to? - Cytoskeleton What does a receptor do? - Binds to chemical messengers such as hormones sent by other cells What does an enzyme do? - Breaks down a chemical messenger and terminates its effect What is a channel? - Channel protein that is constantly open and allows solutes to pass into and out of cell What are gated channels? - Gates that opens and closes to allow solutes through only at certain times What is a cell-identity