In dark-adapted rod cells, a high level of cGMP keeps cGMP-gated nonselective cation channels open, leading to hyperpolarization of the plasma membrane and neurotransmitter release. 

B - Light absorption generates activated rhodopsin, R*, which binds inactive, GDP-bound Gαt protein and mediates the exchange of GDP for GTP . 

C- The free Gαt∙GTP activates PDE by binding to its inhibitory γ subunits and dissociating them from the catalytic α and β subunits . Relieved of their inhibition, the α and β subunits of PDE hydrolyze GMP to cGMP . 

D- The resulting decrease in cytosolic cGMP leads to dissociation of cGMP from the cation channels in the plasma membrane and the closing of those channels . 

E- The membrane then becomes transiently hyperpolarized, and neurotransmitter release is reduced. 

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#Question id: 35

#Unit 1. Molecules and their Interaction Relevant to Biology

Arrange the following molecular components of an E. coli cell in terms of their percentage of total weight cell.

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#Question id: 26456

#Unit 3. Fundamental Processes

Consensus sequence are

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#Question id: 11040

#Unit 7. System Physiology – Animal

An increase in which of the following would be expected to decrease blood flow in a vessel?

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#Question id: 57

#Unit 1. Molecules and their Interaction Relevant to Biology

A(n) ________ has charge but negligible mass, whereas a(n) ________ has mass but no charge.

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#Question id: 2945

#Unit 2. Cellular Organization

Separation of spindle poles during spindle formation and anaphase B most likely depends on which of the following?