If the middle slice is too narrow, there is no discernible morphogen gradient within it, and regeneration is abnormal.

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#Unit 4. Cell Communication and Cell Signaling

Virulence is due to its potent exotoxin, which destroys the underlying tissue and results in heart, liver, and kidney damage, as well as to suffocation following formation of a tough fibrous membrane in the respiratory tract

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#Unit 4. Cell Communication and Cell Signaling

Malaria (Parasitic)

Sporozoites enter the bloodstream by mosquito.

The sporozoites migrate to the liver, where they multiply, transforming liver hepatocytes into giant multinucleate schizonts, which release thousands of merozoites into the bloodstream. 

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#Unit 4. Cell Communication and Cell Signaling

The merozoites infect red blood cells, which eventually rupture, releasing more merozoites. 

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#Unit 4. Cell Communication and Cell Signaling

Eventually some of the merozoites differentiate into male and female gametocytes, which are ingested by a mosquito and differentiate into gametes in the mosquito’s gut. 

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#Unit 4. Cell Communication and Cell Signaling

The gametes fuse to form a zygote that differentiates to the sporozoite stage within the salivary gland of the mosquito.

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#Id: 9948

#Unit 4. Cell Communication and Cell Signaling

Leishmaniasis

Leishmania is a flagellated protozoan that lives in the phagosomes of macrophages and is transmitted by sand flies.