Exam 7: Membranes: Their Structure,function,and Chemistry

The structures of porin proteins in bacterial membranes and mitochondrial and chloroplast outer membranes is atypical for multipass integral proteins,because the porin transmembrane region is composed of a ________ instead of ________ transmembrane segments as in bacteriorhodopsin.

Substances that can readily pass through the cell membrane are chemically ________ in nature.

Hopanoids are

Which of the following types of protein would be most easily removed from a membrane by changing pH or ionic strength?

Which of the following proposed the "sandwich" model of membranes,in which lipid bilayers are coated on both sides with thin sheets of proteins?

You are a microbiologist working with a new species of bacteria thriving in soil at 15°C.In the lab,you find this bacterium adjusts well to growth at 37°C.If this bacterium were "typical," what changes would you expect to find in the fatty acid composition of the membrane as the bacteria undergo homeoviscous adaption?

Recently,consumption of trans fatty acids has been linked to high blood cholesterol levels and increased risk of heart disease.The food industry has responded by decreasing use of "trans fats." Consider the following questions: (a)How do the structures and transition temperatures of trans,cis,and saturated fatty acids differ,and what are the effects on membrane fluidity? (b)Are trans fatty acids abundant in nature? (c)The major source of trans fats is hydrogenated oils.(The trans fats are produced by a side reaction during the hydrogenation process.)Why has the food industry used synthetically produced hydrogenated oils?

Each of the following contributes to the system providing structural support to the erythrocyte plasma membrane except

Each of the following is a function of membranes except

Naturally occurring unsaturated fatty acids typically

When examining an electron micrograph of cells obtained from a new deep-sea life-form,you notice that the plasma membranes appear as two dark lines separated by a lightly stained region.Which of the following investigator(s)used a similar observation as the basis for a model of membrane structure?

Which of the following would best detect a specific carbohydrate sugar on a glycoprotein?

Which of the following diseases results from impaired glycosphingolipid degradation?

The most prominent lipids in animal cell membranes are

Which of the following types of organisms contain sphingomyelin in cell membranes?

________ are small peptide molecules (10-50 amino acids in length)that can disrupt membrane structure.

The number and location of transmembrane segments in an integral membrane protein can be inferred from the amino acid sequence of the protein by a computer-generated

The shift in membrane fluidity from a gel-like state to a more liquid state as temperature rises is known as a ________.

The most common number of carbons in fatty acid hydrocarbon chains of membrane phospholipids is

The composition of lipids in the outer and inner monolayers of cell membrane lipid bilayers is