Question 1

Which of the following characteristics most directly contributes to the rapid evolution and ubiquity of prokaryotes in diverse environments?

Accepted Answer

Their small size, rapid reproduction, and high mutation rates

Question 2

A scientist isolates a prokaryote with a thick peptidoglycan cell wall and no outer membrane. Which classification best describes this organism?

Accepted Answer

Gram-positive bacterium

Question 3

Which structure allows certain prokaryotes to survive extreme heat, desiccation, and chemical damage by entering a dormant state?

Accepted Answer

Endospore

Question 4

A patient is infected with a bacterium that is resistant to many antibiotics. The resistance gene is found on a small, circular DNA molecule separate from the main chromosome. What is this DNA structure called?

Accepted Answer

Plasmid

Question 5

Which of the following best describes the function of fimbriae in prokaryotes?

Accepted Answer

Attachment to surfaces and other cells

Question 6

During bacterial conjugation, which structure is directly involved in the transfer of genetic material between cells?

Accepted Answer

Pilus

Question 7

Which of the following statements about endospores is TRUE?

Accepted Answer

Endospores are dormant structures that can survive harsh conditions.

Question 8

A prokaryote that obtains energy from sunlight and carbon from CO$$_2 is $$best described as a:

Accepted Answer

Photoautotroph

Question 9

Which of the following best explains why antibiotics that target prokaryotic ribosomes do not harm human cells?

Accepted Answer

Prokaryotic ribosomes are structurally different from eukaryotic ribosomes.

Question 10

Which process involves the uptake of naked DNA fragments from the environment by a prokaryotic cell?

Accepted Answer

Transformation

Question 11

A bacterium that can survive with or without oxygen, switching its metabolism accordingly, is classified as a(n):

Accepted Answer

Facultative anaerobe

Question 12

Nitrogen fixation is a critical process in the biosphere. Which equation best represents this process?

Accepted Answer

$$\mathrm{N_2$} \rightarrow \mathrm{NH_3$}$$

Question 13

Which of the following statements about horizontal gene transfer (HGT) in prokaryotes is correct?

Accepted Answer

HGT can transfer genes between unrelated species, increasing genetic diversity.

Question 14

Which of the following is TRUE regarding the evolutionary relationships among the three domains of life?

Accepted Answer

Archaea are more closely related to Eukaryotes than to Bacteria.

Question 15

A researcher discovers a prokaryote living in a hot spring with a temperature of 90$$^\circC $$and a pH of 2. Which terms best describe this organism?

Accepted Answer

Thermophile and acidophile

Question 16

Which of the following statements about proteobacteria is correct?

Accepted Answer

Mitochondria are believed to have evolved from a proteobacterium ancestor.

Question 17

Which of the following is a distinguishing feature of spirochetes?

Accepted Answer

They are spiral-shaped and gram-negative.

Question 18

Cyanobacteria are important in evolutionary history because:

Accepted Answer

They are the likely ancestors of chloroplasts.

Question 19

Which of the following best describes the role of Streptomyces in medicine?

Accepted Answer

It is used to produce antibiotics.

Question 20

A prokaryote is classified as an obligate anaerobe. Which of the following best describes its metabolism?

Accepted Answer

It is poisoned by oxygen and only survives in its absence.

Chapter 27: Bacteria and Archaea – Structure, Function, and Diversity

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