Question 1

Figure 4.12 shows the oligosaccharides attached to membrane lipids thus forming gangliosides that determine the A, B and O blood groups. Which statement regarding the arrangement of sugars is INCORRECT?

Accepted Answer

A) A person with O blood type would have gangliosides with terminal fucose residues only exposed on their glycolipids. 
B) A person with A blood type would have gangliosides with both terminal fucose and terminal N-acetylgalactosamine residues exposed on their glycolipids. 
C) A person with B blood type would have gangliosides with terminal fucose and galactose residues on their glycolipids. 
D) A person with AB blood type would have gangliosides with terminal fucose, terminal N-acetylgalactosamine and terminal galactose residues exposed on their glycolipids. 
E) all statements are correct

Question 2

The temperature at which a lipid bilayer shifts from a fluid state to a crystalline gel is called the _____________.

Accepted Answer

A) transition temperature 
B) temperature optimum 
C) transition series 
D) pH optimum 
E) gelation temperature

Question 3

Tetrahydrocannabinol, the active ingredient in marijuana, binds to receptors located in the ____________ terminals of certain brain neurons. It lowers the likelihood that these neurons will release ___________.

Accepted Answer

A) postsynaptic, neurotransmitters 
B) presynaptic, neurotransmitters 
C) presynaptic, Ca2+ ions 
D) postsynaptic, Ca2+ ions 
E) dendritic, neurotransmitters

Question 4

Why did liposomes not work against diseases as hoped when they were first tried?

Accepted Answer

A) They were not stable enough to last until their target destination. 
B) Immune system phagocytes removed them from the bloodstream before they could exert an effect. 
C) They could not hold water soluble and lipid soluble drugs. 
D) They were targeted incorrectly. 
E) They expanded osmotically and lysed before reaching their target.

Question 5

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?

Accepted Answer

A) the largest 
B) the smallest 
C) the most negative 
D) the most positive 
E) both the largest and the most negative

Question 6

Using the nucleotide sequence of a gene, which of the following can be learned from a computer-based (computational)analysis of the primary amino acid structure of a membrane protein?

Accepted Answer

A) its structure 
B) its orientation within the lipid bilayer 
C) its concentration in each cell 
D) both its structure and its orientation within the lipid bilayer

Question 7

GPI-anchored proteins play an essential role in maintaining the health and integrity of the nervous and cardiovascular systems. When synthesis is altered or defective, diseases such as ______________ can be observed in humans. (Select all that are correct choices)

Accepted Answer

A) sickle cell anemia 
B) paroxysmal nocturnal hemoglobinuria 
C) Creutzfeld-Jakob syndrome variant 
D) aplastic anemia

Question 8

How are the new "stealth liposomes" protected from immune system phagocytes?

Accepted Answer

A) They are kept cold before use. 
B) They are coated with carbohydrates. 
C) They are given a synthetic polymer coating that protects them from immune destruction. 
D) They are loaded with radioactive isotopes. 
E) They are colored red.

Question 9

___________ is a process that strengthens certain synapses by repeated neuron stimulation over a short time period.

Accepted Answer

A) Denaturation 
B) Long term potentiation 
C) Short term memory 
D) Temporality 
E) Long term deviation

Question 10

Neurotechnology bioengineering goals include: (Select all correct choices)

Accepted Answer

A) stimulation of the visual pathway by providing signals to the retina 
B) stimulation of the visual pathway by providing signals to the optic nerve 
C) better coordination signals within prosthetic limb devices 
D) behavior modification signals to control psychotic impulses in criminals

Question 11

You modify the gene for an integral membrane protein so that the cytoplasmic portions of the protein are deleted. When the gene is inserted in cells, what happens to the mobility of this protein in the membrane?

Accepted Answer

A) It moves much greater distances than the intact protein. 
B) It moves much smaller distances than the intact protein. 
C) It does not move at all. 
D) It is not inserted into the membrane so nothing can be learned about their mobility. 
E) It flips to the opposite leaflet.

Question 12

Phosphatidylethanolamine is concentrated in the inner leaflet of the plasma membrane and tends to promote the curvature of the membrane, which is important in _________.

Accepted Answer

A) membrane budding 
B) membrane fragmentation 
C) membrane fusion 
D) signal transduction and membrane fusion 
E) both membrane budding and membrane fusion

Question 13

What is the distinguishing characteristic of a P-type pump?

Accepted Answer

A) It must be pumped during the cycle. 
B) It must be phosphorylated during the cycle. 
C) It must be protonated during the cycle. 
D) It must be methylated during the cycle. 
E) It must be acetylated during the cycle.

Question 14

Usually, optical tweezers drag integral proteins a limited distance before they encounter a barrier that causes their release; upon release, they typically spring backward. What does this suggest?

Accepted Answer

A) the presence of solid barriers 
B) the presence of elastic barriers 
C) the attachment of the proteins to the cytoskeleton 
D) the attachment of the proteins to the endoplasmic reticulum 
E) the presence of rubber in the membrane

Question 15

You fuse a mouse cell and a human cell and then treat the cell with anti-mouse or anti-human protein-directed antibodies that are covalently linked to fluorescent dyes (antibodies to mouse proteins show green fluorescence; antibodies to human proteins show red fluorescence). What does the cell look like after one hour?

Accepted Answer

A) The cell is half red and half green. 
B) The red and green labels are uniformly distributed across the entire membrane. 
C) The red and green labels are distributed in intermingled patches. 
D) The cell appears to be yellow in color. 
E) The cell appears to be brown in color.

Question 16

Which disease is caused by the deterioration of the myelin sheath?

Accepted Answer

A) myasthenia gravis 
B) multiple sclerosis 
C) muscular dystrophy 
D) diabetes mellitus 
E) lupus erythematosus

Question 17

Once the structure of one member of a membrane protein family has been determined, researchers can usually apply a strategy called __________ to learn about the structure and activity of other members of the family.

Accepted Answer

A) heterology modeling 
B) homology mapping 
C) homology modeling 
D) protein mapping 
E) homologous characterization

Question 18

What is thought to be important in maintaining the native structure of the Kv channel membrane protein and promoting its function as a voltage-gated channel?

Accepted Answer

A) negatively charged cholesterol 
B) positively charged sphingolipids 
C) negatively charged phospholipids 
D) positively charged phospholipids 
E) negatively charged sphingolipids

Question 19

What features of the cochlea make providing implants to improve hearing less challenging that attempting to restore mobility?

Accepted Answer

A) The spiral shape of the cochlea is designed to detect different sound frequencies at different positions along its length, which assists in sending the correct signals to auditory neurons. 
B) The length of the cochlea allows multiple electrodes to be spaced efficiently. 
C) The length of the cochlea reduces the need for extremely high density electrode arrays. 
D) All are correct choices.

Exam 4: The Structure and Function of the Plasma Membrane