Answer:
Finally, the chemical messenger is taken back into the presynaptic neuron, ready to be used again. As levels of the neurotransmitter in the synapse decrease, the stimulation of the postsynaptic nerve ends.
Explanation:
The synapse is the space between two neurons. Through this space, neurons communicate.
An action potential causes the release of neurotransmitters from the presynaptic neuron; if there are enough of these specific neurotransmitters to bind to receptors on the postsynaptic neuron, they do and an action potential is now generated on this neuron.
This communication between two neurons must end once it's happened. In order for it to end, the synapse must be free of neurotransmitters. One mechanism to do so is for the neurotransmitters to be taken back into the presynaptic neuron.
Answer:
Believe it or not, mitochondria are their own organisms!
That’s right, they are single celled living beings that hitch a ride inside our cells for security, and in return they make our energy systems run much better than they would. This arrangement started a very long time ago, before we split from our last ancestor with plants, and long before we became multicellular. Other than this arrangement, our DNA has nothing to do with the DNA of the mitochondria (other than synergistic evolution making us more compatible with one another).
For this reason, it is easy to see how mitochondrial DNA differs from nuclear DNA.
First major difference is that we are in different kingdoms and even different super kingdoms to mitochondria (I know there are only meant to be 5 kingdoms but in biology people often use a system based off genetic differences, leading to a huge array of kingdoms that are often really distantly related). So our DNA and mitochondrial DNA share very few similarities. We both replicate our DNA using the same method and have the same base pairs, but the DNA itself says different things.
Another difference is that mitochondria generations are very fast compared to humans’, so their DNA undergoes genetic drift at a much faster rate, and changes more over time. Therefore it is much easier to locate recent changes in populations, for example the migrations out of Africa in the last 200,000 years, or the ethnic backgrounds of different African races, using mitochondrial DNA. In contrast nuclear DNA has fewer fine mutations that can be used as a map for recent events (in the last million years, say).
Mitochondria are passed down from mother to child in animals, so you will always have your mother’s mitochondrial DNA. This is why there is a mitochondrial Eve- this is the last female that is an ancestor of everyone on the planet, and therefore every human possesses direct ancestors of her mitochondria (and her nuclear DNA). In contrast we receive a 50/50 split of nuclear DNA from father and mother.
I hope this helps!
Limestone: Flaky and mainly made of bones.
Shale: Fine grained and made of clay fragments.
Flint: Hard rock made up of mineral quartz. Also can be used to make fire (flint and steel)
Hope this helped you!
Answer:
The answer to your question is:
Explanation:
<u>Double-helix</u> is the structure of dna as first published by james watson and francis crick in 1953.
Answer:
The diversity-stability hypothesis
Explanation:
An hypothesis is defined as a set of idea,explanation or information that you test through study and experimentation. . A hypothesis is is broad and it is not just a random guessing but well planned theory.The stability-diversity hypothesis states that the broader a community the more okay and productive the community will be. This hypothesis drawn from a more stable and productive communities can use their resources at their disposal better and great use.
Stability as a product of variability relative to community abundance.
