Question 1

Which of the following best explains why Archaea can survive in extreme environments such as deep-sea thermal vents?

Accepted Answer

Their membrane lipids are ether-bonded, making them more resilient to heat and harsh conditions.

Question 2

A scientist discovers a new prokaryote that forms a mutualistic relationship with plant roots and helps fix atmospheric nitrogen. To which group does this organism most likely belong?

Accepted Answer

Proteobacteria

Question 3

Which phase of the bacterial growth curve is characterized by a balance between cell division and cell death, resulting in a stable population size?

Accepted Answer

Stationary phase

Question 4

Which of the following statements about horizontal gene transfer is correct?

Accepted Answer

It increases genetic diversity by transferring genes between different species.

Question 5

A bacterium is found to survive in the presence or absence of oxygen. Which term best describes its oxygen response?

Accepted Answer

Facultative aerobe

Question 6

Which structure allows certain bacteria to orient themselves in Earth's magnetic field and locate low-oxygen habitats?

Accepted Answer

Magnetosomes

Question 7

Gram-negative bacteria are more resistant to penicillin than Gram-positive bacteria because:

Accepted Answer

They have an outer envelope of lipopolysaccharides that protects them.

Question 8

Which of the following best describes a chemoautotroph?

Accepted Answer

Uses energy from chemical modification of inorganic compounds to synthesize organic compounds.

Question 9

A lake experiences a sudden increase in cyanobacteria, resulting in a hazardous algae bloom (HAB). Which ecological role of cyanobacteria is most directly responsible for this phenomenon?

Accepted Answer

Photosynthetic production of organic carbon

Question 10

Which of the following is a correct example of mutualism involving bacteria?

Accepted Answer

Rhizobium bacteria fixing nitrogen for legumes

Question 11

Which feature is shared by both Archaea and Eukaryotes but not Bacteria?

Accepted Answer

Histone proteins associated with DNA

Question 12

A scientist is studying a bacterium that can glide across surfaces and also plays a role in bacterial conjugation. Which structure is most likely involved?

Accepted Answer

Pili

Question 13

Which of the following best describes the main function of the slimy mucilage (glycocalyx) in bacteria?

Accepted Answer

It helps bacteria evade host defenses and form biofilms.

Question 14

Which of the following is NOT a typical shape of bacterial cells?

Accepted Answer

Cuboidal (cube-shaped)

Question 15

Which process is used by bacteria to reproduce and is the basis for counting colonies on agar plates?

Accepted Answer

Binary fission

Question 16

A bacterium that must obtain organic molecules for both energy and carbon is classified as a:

Accepted Answer

Chemoheterotroph

Question 17

Which of the following best explains why small cell size is advantageous for bacteria and archaea?

Accepted Answer

It limits the amount of materials in a cell but allows for rapid cell division.

Question 18

Which of the following is a real-world example of a bacterium that can survive extreme radiation and is used in biotechnology for cleaning up radioactive waste?

Accepted Answer

Deinococcus radiodurans

Question 19

Which of the following best describes the ecological role of decomposer bacteria in the carbon cycle?

Accepted Answer

They break down dead organisms to release minerals for reuse.

Question 20

Which of the following is true about the evolutionary relationship between prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes emerged from within the Archaea, specifically the Asgard archaea.

Bacteria, Archaea, and Microbiomes: Diversity, Structure, and Ecological Roles

Study Guide - Practice Questions

Study Guide - Flashcards