Question

1.) Which of the following statement best describes how bacteria in a hot spring control the fluidity of their plasma membrane?

They decrease the percentage of lipids with unsaturated hydrocarbon chains in their plasma membrane

Because they don't synthesize cholesterol, they cannot control membrane fluidity and therefore have a very fluid plasma membrane.

They use cholesterol to prevent membranes from becoming too fluid.

They form lipid rafts to prevent too much fluidity

They increase the percentage of lipids with unsaturated hydrocarbon chains in their plasma membrane.

2.) Which activity can only be done by a transmembrane protein?

To be phosphorylated

To signal from one side of the membrane to the other

To be glycosylated

To associate with other proteins

To bind transiently to a lipid bilayer

Answer 1

1) unsaturated lipids remain in the fluid state even at a low temperature so bacteria in hot springs increase saturated lipids in the membrane and decrease unsaturated lipids so the answer is They decrease the percentage of lipids with unsaturated hydrocarbon chains in their plasma membrane

2) receptor proteins are usually transmembrane proteins which receive a signal ( via a ligand molecule) and send the signal to the cell so the answer is To signal from one side of the membrane to the other