Ch. 27 Study Quiz

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1

Prokaryotes' essential genetic information is located in the

nucleosome.

exospore.

nucleolus.

nucleoid.

plasmids.

nucleoid.

2

Though plants, fungi, and prokaryotes all have cell walls, we place them in different taxa. Which of these observations comes closest to explaining the basis for placing these organisms in different taxa, well before relevant data from molecular systematics became available?

Their cell walls are composed of very different biochemicals.

Some have cell walls only to control osmotic balance.

Some closely resemble animals, which lack cell walls.

Some have cell walls only for support.

Some have cell walls only for protection from herbivores.

Their cell walls are composed of very different biochemicals.

3

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

metabolic characteristics such as chemoautotrophy and photosynthesis

metabolic characteristics such as the production of methane gas

genetic characteristics such as ribosomal RNA sequences

microscopic examination of staining characteristics of the cell wall

ecological characteristics such as the ability to survive in extreme environments

genetic characteristics such as ribosomal RNA sequences

4

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?

plasmolysis

endocytosis

conjugation

horizontal gene transfer

translation

horizontal gene transfer

5

Which of these statements about prokaryotes is correct?

Genetic variation in bacteria is not known to occur, because of their asexual mode of reproduction.

Bacterial cells conjugate to mutually exchange genetic material.

The persistence of bacteria throughout evolutionary time is due to their genetic homogeneity (in other words, sameness).

Their genetic material is confined within vesicles known as plasmids.

They divide by binary fission, without mitosis or meiosis.

They divide by binary fission, without mitosis or meiosis.

6

Match the numbered terms to the description that follows. Choose all appropriate terms.
1. autotroph
2. heterotroph
3. phototroph
4. chemotroph
a prokaryote that obtains both energy and carbon as it decomposes dead organisms

4 only

2 and 4

1, 3, and 4

1 and 3

1 only

2 and 4

7

In general, what is the primary ecological role of prokaryotes?

serving as primary producers in terrestrial environments

metabolizing materials in extreme environments

adding methane to the atmosphere

parasitizing eukaryotes, thus causing diseases

breaking down organic matter

breaking down organic matter