Viral Infections

Virus enters a cell via a cell-surface receptor for which it has affinity and preempts cell biosynthetic machinery to replicate all components of itself, including its genome.

This genome replication step is often error prone, generating numerous mutations.

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#Id: 5096

#Unit 6. System Physiology – Plant

Bacterial phytochrome is an example of a two-component signaling system in which phytochrome functions as a sensor protein that phosphorylates a response regulator.

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#Unit 2. Cellular Organization

Na+/K+ ATPase generates the low cytosolic Na+ and high cytosolic K+ concentrations. 

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#Id: 5554

#Unit 7. System Physiology – Animal

There are two types of intercalated cells: type A and type B

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#Id: 6380

#Unit 2. Cellular Organization

OC are constitutive because repressor protein is unable to bind; this allows RNA polymerase to have unrestrained access to the promoter.  The Oc mutations are cis-acting/cis dominant, because they affect only the contiguous set of structural genes.

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#Id: 1728

#Unit 4. Cell Communication and Cell Signaling

If an allergen binds both IgG and IgE molecules, it will trigger signals through both Fc receptors. The inhibitory signal dominates.