Muscle cells have an abundant, modified smooth ER called the sarcoplasmic reticulum.

The release and reuptake of Ca2+ by the sarcoplasmic reticulum trigger myofibril contraction and relaxation, respectively

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#Id: 6539

#Unit 7. System Physiology – Animal

The insulin receptor is a combination of four subunits held together by disulfide linkages: 

Two alpha subunits 

Two beta subunits

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#Id: 840

#Unit 2. Cellular Organization

Fusicoccin causes irreversible opening of stomata and plant wilting, followed by cell death and fungal colonization

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#Id: 3159

#Unit 3. Fundamental Processes

 Eukaryotic cells have many DNA polymerases. The replication enzymes operate with high fidelity. Except  for the β enzyme, the repair enzymes all have low fidelity.

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#Id: 7120

#Unit 6. System Physiology – Plant

ABA inhibits precocious germination and vivipary ABA accumulates in dormant buds ABA inhibits ga-induced enzyme production

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#Id: 6973

#Unit 8. Inheritance Biology

SEX-CHROMOSOME ANEUPLOIDIES 

The most common aneuploidies seen in living humans.

Aneuploidy of the human sex chromosomes is better tolerated than aneuploidy of autosomes.

AUTOSOMAL ANEUPLOIDIES

There is no mechanism of dosage compensation for autosomes.