The normal membrane potential inside the axon of nerve cells is –70mV, and since this potential can change in nerve cells it is called the resting potential. When a stimulus is applied a brief reversal of the membrane potential, lasting about a millisecond, occurs. This brief reversal is called the action potential
<span>A stimulus can cause the membrane potential to change a little. The voltage-gated ion channels can detect this change, and when the potential reaches –30mV the sodium channels open for 0.5ms. The causes sodium ions to rush in, making the inside of the cell more positive. This phase is referred to as a depolarisation since the normal voltage polarity (negative inside) is reversed (becomes positive inside). </span>
<span>Repolarisation. At a certain point, the depolarisation of the membrane causes the sodium channels to close. As a result the potassium channels open for 0.5ms, causing potassium ions to rush out, making the inside more negative again. Since this restores the original polarity, it is called repolarisation. As the polarity becomes restored, there is a slight ‘overshoot’ in the movement of potassium ions (called hyperpolarisation). The resting membrane potential is restored by the Na+K+ATPase pump.</span>
Answer:
The correct answer will be option-B.
Explanation:
Transfer RNA or tRNA is the RNA molecule associated with the protein synthesis as it adds the specific amino acids to the nascent growing polypeptide.
The structure of the tRNA molecule resembles the shape of a clover leaf and is known as the clover leaf model. The structure contains hydrogen-bonded stems and associated loops. The stems include acceptor stem which posses CCA 3'-terminal group to attach amino acids. The anticodon loop contains an amino acid attachment site. T and D loop contains modified pseudouridine and dihydrouridine.
Thus, Option-B is the correct answer.
Archaea have more complex RNA polymerases than Bacteria, similar to Eucarya.
In an ecosystem, all the trophic level in a food web are closely interlinked and any change in one level is bound to affect the other levels. The various trophic levels may correspond to producers (such as grass and plants), primary consumers (such as deer), secondary consumers (such as tigers or lions, etc.), etc. If we reduce the land available or necessary for sustaining the ecosystem by half (5 acres instead of 10 acres).
