3.2 study guide Flashcards
Rate of transport of D-glucose by GLUT1 increases with increasing concentrations of D-glucose until a
certain threshold. When this concentration threshold is reached, the transport rate remains steady, but
will not increase. Which hallmark of passive transport is this representative of?
a. Facilitated diffusion along a gradient
b. Saturability
c. Specificity
d. None of the above
Saturability
How does GLUT1 lower the activation energy of D-glucose transport
a. Specific intermolecular interactions with D-Glucose in the transporter binding site
b. Hydrolysis of ATP
c. Cotransport with a proton
d. All of the above
e. None of the above
Specific intermolecular interactions with D-Glucose in the transporter binding site
GLUT1 transporter has two types of membrane-spanning domains: 1) those that stabilize the
transporter complex and (2) those that directly form the pore for transport. Given the following amino
acid sequence, which functional domain would you expect it to participate in? GVIALLIMLVIALCMAALVI
a. An alpha helix forming the pore
b. An alpha helix stabilizing the transporter
c. A beta strand forming the pore
d. A fatty acid-interacting beta strand
e. None of these
An alpha helix stabilizing the transporter
What is the function of the proton that is transported by Lactose permease?
a. To aid in conformational change
b. To provide energy to transport lactose against its gradient
c. To change membrane potential
d. Both a and b
e. Both b and c
-To aid in conformational change
-To provide energy to transport lactose against its gradient
What is the role of the chloride bicarbonate exchanger?
a. Maintaining the membrane potential of the plasma membrane
b. Sugar uptake from the blood
c. Signaling at neural synapses
d. Facilitating removal of carbon dioxide
e. None of the above
Facilitating removal of carbon dioxide
Please place the steps of Calcium ion transport by SERCA in the appropriate order:
1. A large conformational change is triggered
2. The N domain phosphorylates the P domain
3. The A domain dephosphorylates the P domain
4. Calcium is released to the other side of the membrane
5. Calcium and ATP bind to SERCA
a. 5, 2, 1, 3, 4
b. 2, 5, 1, 4, 3
c. 2, 5, 1, 3, 4
d. 5, 2, 1, 4, 3
e. 2, 1, 5, 4, 3
5, 2, 1, 4, 3
Calcium and ATP bind to SERCA
The N domain phosphorylates the P domain
A large conformational change is triggered
Calcium is released to the other side of the membrane
The A domain dephosphorylates the P domain
For the Na+ K+ Pump, which is true?
a. Two sodium ions are exported each cycle
b. Two potassium ions are exported each cycle
c. Both ions are transported against their gradient
d. Both ions are transported with their gradient
e. None of the above
Both ions are transported against their gradient
The CFTR transporter exports chloride ions in the lungs and digestive tract. Which is TRUE about
mutations in residue Phe508 of CFT?
a. Mutations in Phe508 cause misfolding
b. Mutations in Phe508 cause cystic fibrosis
c. Mutations in Phe508 result in reduced chloride ion export
d. Mutations in Phe508 are associated with less water exported into the mucosal layer
e. All of the above
All the above
A transporter causes Salmonella to be antibiotic resistant by pumping out antibiotics against the
gradient before they can act within the cell. What type of transporter would you expect this transporter
to be?
a. Voltage gated ion channel
b. An ABC transporter
c. A P type ATPase
d. a V type ATPase
e. None of these
An ABC transporter
Is it most likely that this antibiotic-exporting transporter from question 11:
a. Is a passive transporter
b. Is an active transporter
c. Uses ATP
d. Both a and c
e. Both b and c
Both b and c
You decide to study a new transporter for your graduate school project from a bacterial species that
is of interest for bioreactors because it grows on pulp waste from fruit processing plants. This transporter
imports arabinose for use as a carbon source. In bacteria with this transporter, concentrations of
arabinose inside the bacterial cell can reach levels even greater than that found outside the cell. Which
is true about your transporter?
a. It can transport against the gradient
b. It can only transport with the gradient
c. It requires energy input
d. Both a and c
e Both b and c
It can transport against the gradient
It requires energy input
When you characterize your transporter, you find that for every molecule of arabinose imported, a
proton is also imported. The protons that are imported with your arabinose are actively pumped out of
the cell by a proton-pumping ATPase. Which of the following is your transporter an example of?
a. Passive transport
b. Primary active transport
c. Secondary active transport
d. Diffusion
e. Voltage gated diffusion
Secondary active transport
Activation of a single beta-adrenergic receptor results in activation of around 10 G protein alpha
subunits and downstream activation of more than 100 protein kinase A molecules. This geometric
cascade is representative of which of the five general features of signal transduction?
a. Specificity
b. Amplification
c. Modularity
d. Desensitization
e. Integration
Amplification
