Question 1

A patient sample reveals spherical bacteria arranged in clusters under the microscope. Which term best describes the shape and arrangement of these bacteria?

Accepted Answer

Cocci in clusters

Question 2

Which of the following statements best differentiates a bacterial capsule from a slime layer?

Accepted Answer

A capsule is organized and firmly attached to the cell wall, while a slime layer is unorganized and loosely attached.

Question 3

Which structure is unique to Gram-negative bacteria and plays a role in DNA transfer during conjugation?

Accepted Answer

Sex pili

Question 4

A Gram stain is performed on a mixed bacterial sample. After the procedure, some cells appear purple and others pink. Which structural difference explains this result?

Accepted Answer

Gram-positive bacteria have a thick peptidoglycan layer that retains crystal violet, while Gram-negative bacteria have a thin peptidoglycan layer and an outer membrane that does not retain the dye.

Question 5

Which bacterial genus lacks a cell wall, making it resistant to antibiotics like penicillin that target peptidoglycan synthesis?

Accepted Answer

Mycoplasma

Question 6

Which of the following best defines 'selective permeability' in the context of the bacterial cell membrane?

Accepted Answer

The ability of the membrane to regulate the passage of certain molecules while restricting others.

Question 7

A bacterial cell is placed in a solution with a lower solute concentration than its cytoplasm. What type of solution is this, and what is the likely outcome for the cell?

Accepted Answer

Hypotonic; the cell may swell and potentially burst.

Question 8

Which type of membrane transport requires energy and can move molecules against their concentration gradient?

Accepted Answer

Active transport

Question 9

Why is the bacterial cell wall important for maintaining osmotic pressure?

Accepted Answer

It prevents the cell from swelling and bursting in hypotonic environments by providing structural support.

Question 10

Which of the following is a function of a plasmid in bacterial cells?

Accepted Answer

It carries non-essential genes, such as those for antibiotic resistance, and can replicate independently of the chromosome.

Question 11

Endospores are formed by some bacteria in response to which of the following conditions?

Accepted Answer

Harsh environmental conditions such as nutrient depletion or desiccation

Question 12

Which of the following best describes the difference between prokaryotic and eukaryotic ribosomes?

Accepted Answer

Prokaryotic ribosomes are 70S, while eukaryotic ribosomes are 80S.

Question 13

Which of the following equations represents aerobic respiration?

Accepted Answer

$$\mathrm{C_6H_{12}O_6$} + 6\mathrm{O_2$} \rightarrow 6\mathrm{CO_2$} + 6\mathrm{H_2O}$$

Question 14

Which of the following best describes the difference between catabolism and anabolism?

Accepted Answer

Catabolism breaks down complex molecules to release energy, while anabolism uses energy to build complex molecules.

Question 15

Which of the following statements about enzyme activity is correct?

Accepted Answer

Enzyme activity can be inhibited by both competitive and noncompetitive inhibitors.

Question 16

During glycolysis in prokaryotes, which pathway produces both ATP and NADPH, and is important for biosynthetic reactions?

Accepted Answer

Pentose phosphate pathway

Question 17

In aerobic respiration, where does the electron transport chain occur in prokaryotic cells?

Accepted Answer

Plasma membrane

Question 18

Which of the following is the final electron acceptor in anaerobic respiration?

Accepted Answer

Nitrate ($$\mathrm{NO_3$^-}) or $$sulfate ($$\mathrm{SO_4$^{2-}})$$

Question 19

A bacterium is classified as a chemoheterotroph. Which of the following best describes its metabolic strategy?

Accepted Answer

It uses organic compounds as both an energy and carbon source.

Question 20

Which of the following statements best explains why fermentation is not considered anaerobic respiration?

Accepted Answer

Fermentation does not use an electron transport chain, while anaerobic respiration does.

Bacterial Cell Structure and Microbial Metabolism: Study Guide

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