The conduction of nerve impulses relies upon the movement of positively-charged ions across the nerve cell membrane. The entry of sodium into the cell produces a wave of positive charge that travels down the length of an axon. Then chemicals called neurotransmitters are secreted out of the end of the axon onto the next nerve in the series (the postsynpatic nerve). This narrow space in between neurons is called the synapse. These neurotransmiiters released by the presynaptic nerve bind to receptors on the postsynaptic nerve. The binding of these receptors opens up channels in this second nerve's membrane that allow sodium ions to enter the nerve cell and initiate another wave of positive charge, and so on... The nerve signal can only move as fast as these ions and neurotransmitters can diffuse to generate this process.
<span>As a professional athlete repeats a given activity many times over, the nerve cells "upregulate" their receptors, meaning that they produce additional receptors to put in the membrane. This is just a natural reaction to the nerve being repeatedly stimulated in the same way over and over. When neurotransmitter is secreted from the presynaptic neuron, there are more receptors on the postsynaptic neuron for it to bind, more channels open up, more ions enter in a shorter time and build up positive charge to create the impulse faster, and so the overall effect is faster. </span>
<span>Additionally, there are sheaths of fatty tissue (called myelin) that insulate the charge in the neuron and allow it to be conducted faster. As people age, these sheaths can start to degrade, making the nerve cell more "leaky" and causing the impulse to be conducted more slowly. </span>
Answer: D
Explanation: I Googled it
Answer:
a. the reindeer population exceeded it carrying capacity
Explanation:
not enough food for the reindeers due to an increase in deer population.
Answer:
Yeah, so basically the image is showing restriction enzymes. The job of restriction enzymes is mainly involved in research when scientists use them for cloning human genes. But that's besides the point...
Main thing you have to understand is that restriction enzymes cut at very specific places along DNA sequences. If you look at the restriction enzyme Rsa 1, you can notice that it cuts only between a thymine nucleotide base and an adenine nucleotide base. Next, if ya look at Sty 1 (be careful b/c W can represent adenine or thymine), it cuts only between two directly adjacent cytosine nucleotide bases!
SO.... if we go to Rsa 1, we can find the answers by dividing up the sequences between the pattern we saw in the gray box. It only cuts between adenine and thymine bases. Based on that, we can find the number of fragments created, and the segment lengths (basically just like how many nucleotide bases are in each strand). Hope ya found this helpful!
