Question 1

How do animal cells maintain membrane fluidity,and hence membrane function,in response to decreased temperature?

Accepted Answer

Membrane fluidity normally decreases wit

Question 2

Glycolipids and glycoproteins are especially abundant in the

Accepted Answer

A) nucleus. 
B) mitochondrial inner membrane. 
C) cytosol. 
D) plasma membrane. 
A) nucleus. 
B) mitochondrial inner membrane. 
C) cytosol. 
D) plasma membrane.

Question 3

Which of the following is TRUE regarding lipid-anchored membrane proteins?

Accepted Answer

A) They are only present on the exoplasmic leaflet of the cell. 
B) They are only present on the endoplasmic leaflet of the cell. 
C) They are only present on the cytosolic leaflet of the cell. 
D) They can be present on either the cytosolic or exoplasmic leaflet of the cell. 
A) They are only present on the exoplasmic leaflet of the cell. 
B) They are only present on the endoplasmic leaflet of the cell. 
C) They are only present on the cytosolic leaflet of the cell. 
D) They can be present on either the cytosolic or exoplasmic leaflet of the cell.

Question 4

All the following statements describe biomembranes except:

Accepted Answer

A) Different biomembranes may contain different proportions of the same phospholipids. 
B) The two leaflets of a biomembrane may contain different phospholipids. 
C) Some biomembranes have free edges. 
D) Some phospholipids and cholesterol may cluster to form lipid rafts. 
A) Different biomembranes may contain different proportions of the same phospholipids. 
B) The two leaflets of a biomembrane may contain different phospholipids. 
C) Some biomembranes have free edges. 
D) Some phospholipids and cholesterol may cluster to form lipid rafts.

Question 5

In immunofluorescence studies you always see the small G-protein Ras in a specific region of the cell and,given its protein sequence along with many other proteins localized to this area,you hypothesize that their C-terminal Cys-Ala-Ala-X (X can be any amino acid)motifs may be responsible for targeting these proteins to this subcellular region.To test this hypothesis,you genetically engineer the sequence encoding this motif onto a cDNA encoding green fluorescent protein.When immunofluorescence is used,where specifically would you expect to see GFP localized in the cell?

Accepted Answer

A) in the nucleus 
B) in the cytoplasm 
C) in the Golgi 
D) at the plasma membrane 
A) in the nucleus 
B) in the cytoplasm 
C) in the Golgi 
D) at the plasma membrane

Question 6

What type of simple-pass membrane protein would contain a hydrophobic membrane-spanning α-helix?

Accepted Answer

A) transmembrane protein 
B) integral membrane protein 
C) peripheral protein 
D) transmembrane protein and integral membrane protein 
A) transmembrane protein 
B) integral membrane protein 
C) peripheral protein 
D) transmembrane protein and integral membrane protein

Question 7

Movement of phospholipids from one leaflet to the other

Accepted Answer

A) occurs routinely. 
B) requires cholesterol. 
C) requires flippases. 
D) is impossible. 
A) occurs routinely. 
B) requires cholesterol. 
C) requires flippases. 
D) is impossible.

Question 8

How are cholesterol and phospholipids transported between organelles?

Accepted Answer

The final steps in the synthesis of chol

Question 9

Lipid droplets arise from the

Accepted Answer

A) endoplasmic reticulum. 
B) plasma membrane. 
C) cytosol. 
D) exoplasm. 
A) endoplasmic reticulum. 
B) plasma membrane. 
C) cytosol. 
D) exoplasm.

Question 10

Sphingolipids are considered amphipathic glycolipids if:

Accepted Answer

A) their polar head groups are sugars that are not linked to the tails via a phosphate group. 
B) they are phospholipids with a one-chain hydrophobic tail. 
C) have one fatty acyl chain attached to carbon 2 of glycerol. 
D) none of the above 
A) their polar head groups are sugars that are not linked to the tails via a phosphate group. 
B) they are phospholipids with a one-chain hydrophobic tail. 
C) have one fatty acyl chain attached to carbon 2 of glycerol. 
D) none of the above

Question 11

Which of the following classes of lipids is (are)present in biomembranes?

Accepted Answer

A) phosphoglycerides 
B) sphingolipids 
C) sterols 
D) all of the above 
A) phosphoglycerides 
B) sphingolipids 
C) sterols 
D) all of the above

Question 12

Cholesterol mixes with phospholipids in a biomembrane because cholesterol molecules are

Accepted Answer

A) amphipathic. 
B) steroid derivatives. 
C) entirely hydrophobic. 
D) phospholipid derivatives. 
A) amphipathic. 
B) steroid derivatives. 
C) entirely hydrophobic. 
D) phospholipid derivatives.

Question 13

When examined by fluorescence recovery after photobleaching (FRAP),certain integral membrane proteins are significantly less mobile than others.What accounts for this reduced mobility?

Accepted Answer

The decreased mobility of cert

Question 14

Which two organelles are responsible for producing phospholipids and sphingolipids?

Accepted Answer

A) mitochondria and proteasome 
B) endoplasmic reticulum and mitochondria 
C) Golgi complex and persoxisome 
D) endoplasmic reticulum and Golgi complex 
A) mitochondria and proteasome 
B) endoplasmic reticulum and mitochondria 
C) Golgi complex and persoxisome 
D) endoplasmic reticulum and Golgi complex

Question 15

What are the primary functions of the plasma membrane in all cells?

Accepted Answer

In both bacteria and higher eukaryotic c

Question 16

Phospholipids with short or unsaturated fatty acyl chains

Accepted Answer

A) decrease membrane fluidity. 
B) increase membrane fluidity. 
C) cause biomembranes to become thicker. 
D) allow hydrophilic molecules to diffuse across the lipid bilayer. 
A) decrease membrane fluidity. 
B) increase membrane fluidity. 
C) cause biomembranes to become thicker. 
D) allow hydrophilic molecules to diffuse across the lipid bilayer.

Question 17

Porins

Accepted Answer

A) are peripheral membrane proteins. 
B) contain no hydrophobic amino acid residues. 
C) have many hydrophobic α-helical regions. 
D) allow small hydrophilic molecules to pass through a membrane. 
A) are peripheral membrane proteins. 
B) contain no hydrophobic amino acid residues. 
C) have many hydrophobic α-helical regions. 
D) allow small hydrophilic molecules to pass through a membrane.

How do animal cells maintain membrane fluidity,and hence membrane function,in response to decreased temperature?

Glycolipids and glycoproteins are especially abundant in the

Which of the following is TRUE regarding lipid-anchored membrane proteins?

All the following statements describe biomembranes except:

What type of simple-pass membrane protein would contain a hydrophobic membrane-spanning α-helix?

Movement of phospholipids from one leaflet to the other

How are cholesterol and phospholipids transported between organelles?

Lipid droplets arise from the

Sphingolipids are considered amphipathic glycolipids if:

Which of the following classes of lipids is (are)present in biomembranes?

Cholesterol mixes with phospholipids in a biomembrane because cholesterol molecules are

When examined by fluorescence recovery after photobleaching (FRAP),certain integral membrane proteins are significantly less mobile than others.What accounts for this reduced mobility?

Which two organelles are responsible for producing phospholipids and sphingolipids?

What are the primary functions of the plasma membrane in all cells?

Phospholipids with short or unsaturated fatty acyl chains

Porins

Chemical Foundations

Molecular Genetic Techniques

Protein Structure and Function

Culturing and Visualizing Cells

Fundamental Molecular Genetic Mechanisms

Genes Genomics and Chromosomes

Transcriptional Control of Gene Expression

Post-Transcriptional Gene Control

Transmembrane Transport of Ions and Small Molecules

Cellular Energetics

Moving Proteins Into Membranes and Organelles

Vesicular Traffic, Secretion, and Endocytosis

Signal Transduction and G-Protein Coupled Receptors

Signaling Pathways That Control Gene Activity

Cell Organization and Movement I: Microfilaments

Cell Organization and Movement II: Microtubules and Intermediate Filaments

Regulating the Eukaryotic Cell Cycle

Integrating Cells Into Tissues

Cell Birth, Lineage, and Death

Nerve Cells

Immunology

Cancer

Filters

Exam 6: Bio-membrane Structure

How do animal cells maintain membrane fluidity,and hence membrane function,in response to decreased temperature?

Glycolipids and glycoproteins are especially abundant in the

Which of the following is TRUE regarding lipid-anchored membrane proteins?

All the following statements describe biomembranes except:

What type of simple-pass membrane protein would contain a hydrophobic membrane-spanning α-helix?

Movement of phospholipids from one leaflet to the other

How are cholesterol and phospholipids transported between organelles?

Lipid droplets arise from the

Sphingolipids are considered amphipathic glycolipids if:

Which of the following classes of lipids is (are)present in biomembranes?

Cholesterol mixes with phospholipids in a biomembrane because cholesterol molecules are

When examined by fluorescence recovery after photobleaching (FRAP),certain integral membrane proteins are significantly less mobile than others.What accounts for this reduced mobility?

Which two organelles are responsible for producing phospholipids and sphingolipids?

What are the primary functions of the plasma membrane in all cells?

Phospholipids with short or unsaturated fatty acyl chains

Porins

Chemical Foundations

Molecular Genetic Techniques

Protein Structure and Function

Culturing and Visualizing Cells

Fundamental Molecular Genetic Mechanisms

Genes Genomics and Chromosomes

Transcriptional Control of Gene Expression

Post-Transcriptional Gene Control

Transmembrane Transport of Ions and Small Molecules

Cellular Energetics

Moving Proteins Into Membranes and Organelles

Vesicular Traffic, Secretion, and Endocytosis

Signal Transduction and G-Protein Coupled Receptors

Signaling Pathways That Control Gene Activity

Cell Organization and Movement I: Microfilaments

Cell Organization and Movement II: Microtubules and Intermediate Filaments

Regulating the Eukaryotic Cell Cycle

Integrating Cells Into Tissues

Cell Birth, Lineage, and Death

Nerve Cells

Immunology

Cancer

Filters