Answer:
c) 3
Explanation:
Cellular respiration includes following 3 processes:
1) Glycolysis
2) Citric acid cycle or TCA or Kreb's cycle
3) Electron Transport Chain (ETC)
In glycolysis, a 3 carbon compound known as pyruvate is produced from glucose. Each glucose molecule produces 2 pyruvate molecules. Each pyruvate molecule then enters a complex known as Pyruvate dehydrogenase complex wherein the pyruvate molecule further undergoes oxidative decarboxylation to produce a 2 carbon compound known as Acetyl-CoA.
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The Acetyl-CoA then enters citric acid cycle or TCA or Kreb's cycle wherein this Acetyl-CoA and oxaloacetate are oxidized to produce CO₂ molecules in eight steps. Each glucose molecule is capable of producing six CO₂ after the completion of citric acid cycle. Since one glucose molecule produces 2 pyruvate molecules then it means <u>a pyruvate molecule will be able to produce three CO₂.</u>
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>
<span>The answer is : Both have true necks, while eusthenopteron has no neck. </span>We know that tiktaalik is more closely related to acanthostega than it is Ichthyostega eusthenopteron because Tiktaalik and Acanthostega both have true necks while eusthenopteron has none.
