The presence of a mutant lac repressor that could not bind lactose would result in no transcription even when lactose was present because the mutant repressor would remain bound to the lac operator
The transcription of lac operator is controlled by the lac repressor. When lactose is present, the lac repressor normally will bind to the lactose, removing itself from the lac operator so it could be transcripted.
In this case, the mutation makes the lac repressor keep binding to the lac operator so the result would be no transcription even when lactose present.
Without energy, nothing would exists. we wouldn’t even exist.
I believe that
Stones can form from substances in the bile while it is stored in the gallbladder, this condition is called Gallstones.
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Answer:
The correct answers are: Synaptic Active Zones, Exocytosis.
Explanation:
- An impulse after travelling along the dendrites, cell body and axon of a neuron reaches the axon endings in the form of an action potential (signal transmitted by the activation of voltage gated sodium and potassium channels present on the plasma membrane of the neurons).
- At the axon ending or the pre-synaptic region, the action potential triggers the opening of the voltage dependent calcium channels, that promotes the influx of calcium ions into the pre-synaptic region of the neuron.
- This process triggers the fusion of the neuro-transmitter carrying vesicles with the plasma membrane in the pre-synaptic region of the neuron.
- As a result of fusion the neurotransmitter is released into the synaptic cleft.
- At the pre-synaptic region of the neuron, there is a huge concentration of neuro-transmitter carrying vesicles which remain adhered to proteins called CAZ (cytomatrix at the active zone) proteins. These proteins help the neurotransmitter carrying vesicles to remain tethered or docked to the pre-synaptic membrane in the axon terminal of the neuron. They together form the Synaptic Active Zone.
- In response to calcium ion influx these proteins help the neurotransmitter carrying vesicles to fuse with the plasma membrane in the pre-synaptic region of the neural axon and release the neurotransmitter into the synaptic cleft.
- The process of fusion of the neurotransmitter carrying vesicles with the plasma membrane in the pre-synaptic region of the neural axon followed by the release of the neurotransmitter into the synaptic cleft is known as Exocytosis.
Firstly they are not membranes and they are villi's which increase the surface area during digestion
