Correct option is C
Option 3: F-D-B-E-A-C is the correct answer.
Explanation:
Here’s a detailed breakdown of the phototransduction process in rod cells upon light exposure:
F: Conformational change in rhodopsin
Rhodopsin, a light-sensitive protein in rod cells, undergoes a conformational change when it absorbs light. This is the first step in phototransduction.
D: Activation of transducin
The conformational change in rhodopsin activates transducin, a G-protein. This is a crucial step in the signal transduction pathway.
B: Activation of phosphodiesterase
Transducin activates phosphodiesterase, which is an enzyme responsible for breaking down cGMP (cyclic guanosine monophosphate) in the cell.
E: Decreased intracellular cGMP
Phosphodiesterase lowers the levels of cGMP in the rod cell, which is essential for the subsequent steps in phototransduction.
A: Hyperpolarization
As a result of the decrease in cGMP, the cation channels close, leading to hyperpolarization of the rod cell. This changes the electrical state of the cell and initiates a signal to be transmitted to the brain.
C: Decreased release of synaptic transmitter
The hyperpolarization of the rod cell results in a decreased release of synaptic transmitters at the synapse, which signals the processing of the visual information.
Conclusion:
The correct sequence of events in the phototransduction pathway is:
F (Conformational change in rhodopsin) → D (Activation of transducin) → B (Activation of phosphodiesterase) → E (Decreased intracellular cGMP) → A (Hyperpolarization) → C (Decreased release of synaptic transmitter).
