The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.

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3 years ago

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Under anaerobic conditions, such as intense exercise, pyruvate is converted to ____________ . This 3-carbon molecule travels thr

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Answer:

Under anaerobic conditions, such as intense exercise, pyruvate is converted to lactate. This 3-carbon molecule travels through the blood to the liver, where it can be converted to glucose by the cori cycle.

Under aerobic conditions, pyruvate enters the mitochondrion, where it is converted to acetyle CoA . This 2-carbon molecule goes on to participate in a series of oxidative reactions called the Citric acid cycle.

Explanation:

In the question ,among the given 6 options ,the simplest way to find the answer can be ,to find either the option is aerobic (presence of free oxygen ) or anaerobic (lack of free oxygen). Among the options , glucose is an incorrect option as it is a carbohydrate and used in respiration process .In aerobic process ,the glucose can be break down but in anaerobic ,it can only be used.

Other option is ATP- ATP is the energy source of the cell and used for storing energy or reactions of the cell,thus this option do not belong to the given question.

thus its clear the rest four options are the answer .

among four two options belong to aerobic and the rest two are anaerobic.

Under anaerobic conditions-

The pyruvate is converted into lactate because under the absence of oxygen only the NAD+ can be regenerated, thus further can allow glycolysis.

The cori cycle is also called lactic acidic cycle, thus this cycle is a metabollic pathway produced by anaerobic glycolysis (which takes place by regeneration of NAD+)transporting the molecules from blood to liver and further converting to glucose

Under aerobic conditions,-

The pyruvate is converted into Acetyle CoA so as to further produce citric acid and then citric acidic cycle. Thus Acetyle CoA forms more ATP which help in the regeneration of NAD+ and production of citric acid cycle takes place.

HENCE , The correct options are - lactate cori acetyle CoA citric acid.

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3 years ago