Hyperthermophilic Archaea Possess an Unusual Gyrase Called __________, Which Introduces

question 47

Multiple Choice

Hyperthermophilic archaea possess an unusual gyrase called __________, which introduces positive supercoils into the chromosome in order to protect the DNA from __________.

• A) DNA ligase; thermal denaturation
• B) DNA helicase; thermal denaturation
• C) reverse DNA gyrase; excessive gene expression
• D) reverse DNA gyrase; thermal denaturation
• E) reverse transcriptase; excessive gene expression

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Definitions:

Pepsinogen

Proenzyme formed and secreted by the chief cells of the gastric mucosa; the acidity of the gastric juice and pepsin itself converts pepsinogen into pepsin.

Zymogen Granules

Intracellular storage granules found in the pancreas and other glands, containing inactive enzyme precursors that can be activated when needed.

Salivary Amylase

An enzyme found in saliva that starts the process of breaking down starches into sugars during digestion.

Pyloric Pump

A mechanism involving the pylorus, the region of the stomach that connects to the small intestine, which regulates the passage of digestive contents into the intestine.