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

Which of the following molecules would enter the cell via a specialized transmembrane receptor?

The likely number of and locations of transmembrane segments of integral membrane proteins is inferred by

The venom of black widow spiders (Latrodectus mactans)contains an enzyme that hydrolyzes lecithin to the phospholipid lysolecithin.The lysolecithin lyses red blood cells,destroying them.One possible mechanism whereby lysolecithin disrupts the plasma membranes of red blood cells is that it

Many integral membrane proteins have not been analyzed by X-ray crystallography. However,transmembrane segments can be inferred using computer analysis of the amino Acid sequence of the protein.This technique is known as

Temperature has a dramatic effect upon cell membranes.This influence can readily make a cell membrane more solid or more fluid in response to the temperature.This is an example of

________ is the name of the technique used for the analysis of membrane lipids.

Trypsin is a hydrophilic protease and therefore is unable to cross the plasma membrane and enter a cell.However,it is capable of digesting the hydrophilic portions of membrane proteins.As a result of these properties,researchers investigating membrane proteins have treated cells with trypsin then separated the proteins by SDS-PAGE to gain insight into the orientation of particular proteins within the membrane.Describe an experiment using this information and the results you would expect with the following types of membrane-associated proteins.(Assume the proteins are single polypeptides.) a.an integral membrane protein with the N-terminus exposed on the surface b.an integral membrane protein with the C-terminus exposed on the surface c.an integral membrane protein with three hydrophilic loops (only)exposed on the surface d.a membrane-associated protein facing the cytoplasm e.an imbedded membrane protein

With regard to the semipermeable nature of the plasma membrane,which of the following would readily cross without the aid of a transport protein?

To facilitate the regulation of membrane fluidity,E.coli has the enzyme

With respect to the outer and inner faces of the lipid bilayer of the cell membrane,the composition of lipids is

A colleague gives you two membrane fractions from a plant cell lysate.One contains the plasma membrane fraction,the other the mitochondrial fraction.The tubes are not labeled,but you run the samples anyway,looking at the macromolecule composition of the samples.You know for certain that the second sample contains the mitochondrial fraction simply because it contains insignificant amounts of

The scientist(s)who developed the "sandwich" model of the cell membrane is (are)

Which of the following is not a function of membranes?

Most unsaturated fatty acids are in the ________ configuration,but some are in the ________ configuration,making their shape more like that of saturated fatty acids.

Based on your knowledge of the chemistry of the cell membrane,which of the following compounds would you couple with a new drug in order to achieve better uptake by cells?

________ are small peptide molecules (10-50 amino acids in length)that affect membrane permeability.

The shifting of membrane fluidity from a gel-like to a more liquid state is known as ________.

Transmembrane proteins involved in detecting external stimuli and relaying that information to the cell are most likely ________ proteins.

Two cells with different cell-surface markers are fused in the presence of polyethylene glycol (PEG).The cells are then placed at 0°C.What do you expect to observe about the individual cell markers?

The ability of some organisms to compensate for temperature changes by altering the lipid composition of membrane lipids is known as