When lactose enters the cell, it is converted to allolactose. It is allolactose (rather than lactose itself) that controls the Lac repressor. Paradoxically, the conversion of lactose to allolactose is catalyzed by b-galactosidase, itself encoded by one of the lac genes. How is this possible? Which statement is incorrect according lac genes expressions?

#Question id: 11394

#Unit 9. Diversity of Life Forms

Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods would not generally inhibit bacterial growth?

#Question id: 11395

#Unit 9. Diversity of Life Forms

Mitochondria are thought to be the descendants of certain alpha -proteobacteria. They are, however, no longer able to lead independent lives because most

genes originally present on their chromosome have moved to the nuclear genome. Which phenomenon accounts for the movement of these genes?

#Question id: 11396

#Unit 9. Diversity of Life Forms

Carl Woese and collaborators identified two major branches of prokaryotic evolution. What was the basis for dividing prokaryotes into two domains?

#Question id: 11397

#Unit 9. Diversity of Life Forms

Which statement about the domain Archaea is false?

#Question id: 11398

#Unit 9. Diversity of Life Forms

Assuming that each of these possesses a cell wall, which prokaryotes should be expected to be most strongly resistant to plasmolysis in hypertonic environments?

#Question id: 11399

#Unit 9. Diversity of Life Forms

The thermoacidophile, Sulfolobus acidocaldarius lacks peptidoglycan. What is likely to be true of this species?

1. It is a bacterium.

2. It is an archaean.

3. The optimal pH of its enzymes will lie above pH 7.

4. The optimal pH of its enzymes will lie below pH 7.

5. It could inhabit certain hydrothermal springs.

6. It could inhabit alkaline hot springs.