Question 1

Which bacterial cell shape is depicted in the first image, and what is the biological significance of this morphology?

Accepted Answer

Coccus; provides resistance to desiccation and osmotic stress

Question 2

Referencing the third image, why do smaller microbial cells generally have a higher rate of nutrient exchange compared to larger cells?

Accepted Answer

Because their surface area to volume ratio is higher, as shown by $$\frac{Surface}{Volume}$$ values

Question 3

Which of the following best explains why penicillin is effective against Gram-positive bacteria but less so against Gram-negative bacteria?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer that is the primary target of penicillin

Question 4

Which component of the Gram-negative cell wall is responsible for its toxicity in humans?

Accepted Answer

Lipid A of lipopolysaccharide (LPS)

Question 5

A bacterium is found to be resistant to penicillin and lacks a cell wall. Which genus is it most likely to belong to?

Accepted Answer

Mycoplasma

Question 6

Which structure allows bacteria to adhere to surfaces and evade immune defenses, and what is its main chemical composition?

Accepted Answer

Capsule (glycocalyx); composed mainly of carbohydrates

Question 7

Which of the following best describes the function of the plasma membrane in prokaryotes?

Accepted Answer

It acts as a selective barrier and is involved in energy transformation

Question 8

A molecule is highly charged and hydrophilic. Based on the structure of the plasma membrane, will it freely cross the membrane? Why or why not?

Accepted Answer

No, because the hydrophobic core of the lipid bilayer prevents passage of charged molecules

Question 9

Which of the following is a function of bacterial flagella?

Accepted Answer

Motility towards or away from environmental cues (taxis)

Question 10

What is the primary role of the pilus in bacteria?

Accepted Answer

Transfer of genetic material during conjugation

Question 11

Which of the following statements about the bacterial chromosome is correct?

Accepted Answer

It is circular, double-stranded, and located in the nucleoid region

Question 12

What is the significance of the 70S ribosome in bacteria?

Accepted Answer

It is the site of protein synthesis and is composed of 30S and 50S subunits

Question 13

Which of the following best describes the function of endospores in bacteria?

Accepted Answer

They allow bacteria to survive extreme conditions such as heat, desiccation, and chemicals

Question 14

Which of the following is a distinguishing feature of eukaryotic cells compared to prokaryotic cells?

Accepted Answer

Presence of membrane-bound organelles such as mitochondria and nucleus

Question 15

Which eukaryotic microbes possess cell walls, and how do their cell walls differ from those of bacteria?

Accepted Answer

Fungi and algae; their cell walls are composed of different molecules than bacterial peptidoglycan

Question 16

Which of the following best explains why Gram-negative bacteria are generally more resistant to antibiotics than Gram-positive bacteria?

Accepted Answer

Their outer membrane acts as a barrier to many antibiotics

Question 17

Which of the following is a function of storage granules in bacteria?

Accepted Answer

Storage of organic and inorganic molecules such as phosphate

Question 18

Which of the following best describes the process of facilitated diffusion across the plasma membrane?

Accepted Answer

It involves transport proteins and moves substances down their concentration gradient

Question 19

Which of the following is a unique feature of the Gram-positive cell wall?

Accepted Answer

Presence of teichoic acids

Question 20

A scientist is using a transmission electron microscope (TEM) to observe bacterial cells. Which of the following is a limitation of this technique?

Accepted Answer

Samples must be fixed, stained with heavy metals, and observed in a vacuum

Microbial Cell Structure & Function: Prokaryotic and Eukaryotic Cells

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