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

In response to temperature changes,cell membranes change state to become more solid or more fluid by undergoing

Which of the following lipids is found concentrated in lipid rafts in animal cell plasma membranes?

Transmembrane proteins involved in detecting external chemical signals and relaying that information to the cell are known as ________ proteins.

Membrane lipids can be separated by ________,based on their ________.

Hydropathy analysis of a membrane protein's amino acid sequence predicts the protein's transmembrane segments and orientation in the membrane.It is necessary to confirm those predictions with experimental analysis.One experimental approach for plasma membrane proteins is to use the protease trypsin to digest extracellular domains of these proteins.(Trypsin is hydrophilic and cannot cross the plasma membrane to enter the cell.)When added to cells,trypsin digests the hydrophilic portions of plasma membrane proteins exposed outside the cell into small fragments but will not have access to transmembrane or cytosolic regions of proteins.Design a general experiment using trypsin and SDS-PAGE to address membrane protein association and orientation,and describe specific expected results that would be consistent with the following predicted membrane protein associations and orientations: a.a singlepass integral membrane protein with only its N-terminus exposed on the extracellular surface b.a singlepass integral membrane protein with only its C-terminus exposed on the extracellular surface c.a multipass integral membrane protein with only three hydrophilic loops exposed on the extracellular surface d.a fatty acylated protein e.a GPI-anchored protein

Which of the following would be the most thermodynamically unfavorable membrane lipid activity in a membrane?

Of the following molecules,which would you predict diffuses most readily across membranes?

Using a laser beam to inactivate fluorescence dye molecules connected to proteins or lipids on a cell membrane is called

When a mouse cell and a human cell with different cell-surface protein markers are fused using polyethylene glycol (PEG)and immediately placed at 0°C,what would you expect happens to the mouse and human marker proteins?

The current understanding of cell membrane structure is based on the ________ model.

The presence of trans fats in membranes ________ (increases or decreases)membrane fluidity and ________ (increases or decreases)the membrane transition temperature.

The ability of some organisms to alter their membrane lipid composition in response to changes in temperature is known as ________.

The E.coli enzyme responsible for creating unsaturated bonds from saturated bonds in the cell membrane fatty acids at a lower environmental temperature is ________.

Amphipathic cationic antimicrobial peptides (AMPs)have potential as novel therapeutic agents in the treatment of skin bacterial diseases such as leprosy (caused by Mycobacterium leprae).Describe the nature of AMPs,where they can be found in nature,the mechanism by which amphipathic cationic AMPs kill bacteria,and how such AMPS could be developed into a treatment for leprosy.

Which of the following lipids would you expect to find associated with chloroplast membranes?

Which of the following is true about glycosylated plasma membrane proteins?

Which of the following would you expect to find predominating in the plasma membrane of a unicellular eukaryotic organism thriving in glacier ice?

Cholesterol

E.coli uses which of the following enzymes to regulate membrane fluidity?

Each of the following is true about homeoviscous adaptation in membranes except