Question 1

Which of the following statements best describes a key structural difference between prokaryotic and eukaryotic cells?

Accepted Answer

Eukaryotic cells have a nucleus surrounded by a nuclear envelope, whereas prokaryotic cells lack a true nucleus.

Question 2

Most microbial cells on Earth are found in which environment?

Accepted Answer

Subsoil

Question 3

Which of the following is NOT a beneficial aspect of microorganisms in our lives and environment?

Accepted Answer

Causing infectious diseases

Question 4

Which scientist is credited with the first observation of microorganisms using a simple microscope?

Accepted Answer

Antoni van Leeuwenhoek

Question 5

How many domains are recognized in modern taxonomy, and which characteristic is unique to the Archaea domain?

Accepted Answer

Three domains; Archaea possess ether-linked membrane lipids.

Question 6

Why are small subunit ribosomal RNA (SSU rRNA) genes, such as 16S rRNA, used in determining phylogeny?

Accepted Answer

They are universally present, highly conserved, and contain variable regions suitable for comparison.

Question 7

Which evidence supports the close relationship between Eukarya and Archaea?

Accepted Answer

Both lack sensitivity to antibiotics targeting bacterial ribosomes.

Question 8

What is the threshold of 16S rRNA gene sequence similarity used to define a prokaryotic species?

Accepted Answer

$$\geq 97\%$$ sequence similarity

Question 9

Which bacterial genus is known for producing antibiotics and has a filamentous structure similar to fungi?

Accepted Answer

Streptomyces

Question 10

What is the difference between magnification and resolution in microscopy?

Accepted Answer

Magnification is the enlargement of an image, while resolution is the ability to distinguish two points as separate.

Question 11

Given the formula for resolving power $$RP = 0.5 	imes 	ext{wavelength} / 	ext{NA}$$, which change will improve resolution?

Accepted Answer

Using immersion oil to increase NA

Question 12

Which staining technique is used to differentiate bacteria based on the composition of their cell wall?

Accepted Answer

Gram stain

Question 13

Which cell shape and arrangement is described as spherical cells in clusters?

Accepted Answer

Coccus in clusters

Question 14

Why is a high surface area to volume (SA/V) ratio significant for bacterial cells?

Accepted Answer

It allows for efficient transport of nutrients and waste.

Question 15

Which feature distinguishes archaeal membranes from bacterial membranes?

Accepted Answer

Presence of ether linkages and isoprene units

Question 16

Which nutrient transport mechanism involves chemical modification of the transported molecule?

Accepted Answer

Group translocation

Question 17

How does penicillin affect bacterial cell walls?

Accepted Answer

It inhibits the synthesis of peptide cross-bridges in peptidoglycan.

Question 18

Which bacteria lack cell walls and are therefore resistant to antibiotics targeting peptidoglycan?

Accepted Answer

Mycoplasma

Question 19

Which bacterial structure is responsible for motility and can be arranged as polar, peritrichous, or lophotrichous?

Accepted Answer

Flagella

Question 20

Which metabolic classification describes organisms that use organic compounds for both energy and carbon?

Accepted Answer

Chemoorganotrophs

Foundations of Microbiology: Cell Structure, Diversity, and Metabolism

Study Guide - Practice Questions