Question 1

Which adaptation allows Halobacterium (an archaeon) to thrive in the highly saline waters of Laguna Salada de Torrevieja, as shown in the first image?

Accepted Answer

Specialized proteins and cell membrane structures that prevent dehydration and maintain osmotic balance

Question 2

Which of the following best explains why prokaryotes can reach huge population sizes and adapt rapidly to changing environments?

Accepted Answer

They are small, reproduce quickly by binary fission, and accumulate mutations rapidly

Question 3

Which of the following is NOT a typical shape found among prokaryotes?

Accepted Answer

Cuboidal (cube-shaped)

Question 4

Why do most prokaryotes lose water and experience plasmolysis in hypertonic environments?

Accepted Answer

Water moves out of the cell due to osmosis, causing the plasma membrane to pull away from the cell wall

Question 5

Which statement correctly distinguishes between gram-positive and gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer that retains crystal violet dye, while gram-negative bacteria have a thin peptidoglycan layer and an outer membrane

Question 6

Why are gram-negative bacteria generally more resistant to antibiotics than gram-positive bacteria?

Accepted Answer

Their outer membrane impedes the entry of many antibiotics

Question 7

What is the function of a bacterial capsule, as seen in the image of a bacterium with a capsule?

Accepted Answer

It enables adherence to surfaces, prevents dehydration, and protects against the host immune system

Question 8

Endospores, as shown in the electron micrograph, allow bacteria to:

Accepted Answer

Survive extreme environmental conditions for long periods

Question 9

Fimbriae and pili are important for prokaryotes because they:

Accepted Answer

Facilitate attachment to surfaces and, in the case of pili, exchange of DNA between cells

Question 10

Which structure is primarily responsible for prokaryotic motility, and how does it differ from its eukaryotic counterpart?

Accepted Answer

Flagella; prokaryotic flagella are structurally and compositionally different from eukaryotic flagella

Question 11

Which of the following best describes the genetic material of prokaryotes?

Accepted Answer

One circular chromosome located in a nucleoid region, sometimes with plasmids

Question 12

Why can antibiotics target bacterial cells without harming human cells?

Accepted Answer

Human cells lack peptidoglycan, which is targeted by many antibiotics

Question 13

Which process is responsible for the rapid increase in genetic diversity among prokaryotes?

Accepted Answer

Mutation and genetic recombination through transformation, transduction, and conjugation

Question 14

During bacterial conjugation, what is the role of the F factor?

Accepted Answer

It is required for the production of pili and can exist as a plasmid or chromosomal segment

Question 15

Which nutritional mode describes an organism that uses light for energy and organic compounds for carbon?

Accepted Answer

Photoheterotroph

Question 16

A bacterium that can use $$\mathrm{O}_2$$ for cellular respiration but can also survive by fermentation if $$\mathrm{O}_2 is $$absent is classified as:

Accepted Answer

Facultative anaerobe

Question 17

Nitrogen fixation is a process by which certain prokaryotes:

Accepted Answer

Convert atmospheric nitrogen ($$\mathrm{N}_2) $$into ammonia ($$\mathrm{NH}_3)$$

Question 18

Biofilms are problematic in medical and industrial settings because they:

Accepted Answer

Can cause chronic, antibiotic-resistant infections and corrosion of structures

Question 19

Which ecological relationship describes a situation where one organism benefits and the other is neither helped nor harmed?

Accepted Answer

Commensalism

Question 20

Which of the following is a real-world example of horizontal gene transfer contributing to human health problems?

Accepted Answer

The spread of antibiotic resistance genes among bacterial populations

Bacteria and Archaea: Structure, Function, Diversity, and Roles in the Biosphere

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