Question 1

Which of the following best describes the endosymbiotic theory for the origin of mitochondria in eukaryotic cells?

Accepted Answer

Mitochondria originated from a symbiotic relationship where an ancestral eukaryotic cell engulfed an aerobic prokaryote, which then became a permanent organelle.

Question 2

A newly discovered microbe is found to have peptidoglycan in its cell wall, a single circular chromosome, and no membrane-bound organelles. Based on these features, to which domain does this microbe most likely belong?

Accepted Answer

Bacteria

Question 3

Which process allows bacteria to survive in nutrient-poor environments by forming a dormant, highly resistant structure?

Accepted Answer

Endospore formation

Question 4

Which equation correctly represents the calculation of evolutionary distance between two organisms based on the number of nucleotide differences in a gene sequence?

Accepted Answer

$d = \frac{n}{L}$

Question 5

A patient presents with a bacterial infection. The bacteria are found to lack peptidoglycan in their cell walls. Which of the following is the most likely explanation?

Accepted Answer

The bacteria belong to the domain Archaea, which often lack peptidoglycan.

Question 6

Which of the following statements about facilitated diffusion is correct?

Accepted Answer

Facilitated diffusion uses membrane proteins to transport molecules down their concentration gradient.

Question 7

Which structure is responsible for motility in both bacterial and eukaryotic cells, but differs in its composition and mechanism?

Accepted Answer

Flagella

Question 8

A Gram-negative bacterium is more resistant to antibiotics than a Gram-positive bacterium. Which feature contributes most to this resistance?

Accepted Answer

Presence of an outer membrane containing lipopolysaccharides

Question 9

Which of the following best explains why compartmentalization of the cell interior is advantageous to eukaryotic cells?

Accepted Answer

It enables simultaneous and specialized biochemical reactions in different organelles.

Question 10

Which of the following is a function of bacterial plasmids?

Accepted Answer

Carrying genes for antibiotic resistance and toxin production

Question 11

A scientist observes binary fission in a bacterial culture. Which step occurs first in this process?

Accepted Answer

Replication of the chromosome

Question 12

Which of the following best describes the function of the nucleolus in eukaryotic cells?

Accepted Answer

Site of ribosomal RNA synthesis and ribosome assembly

Question 13

Which formula correctly represents the calculation of the number of generations ($n$) in a bacterial population given the initial number of cells ($N_0$) and the final number of cells ($N$)?

Accepted Answer

$n = \frac{\log N - \log N_0}{\log 2}$

Question 14

Which of the following is a major difference between prokaryotic and eukaryotic flagella?

Accepted Answer

Prokaryotic flagella rotate, while eukaryotic flagella whip back and forth.

Question 15

Which of the following statements about the structure and function of the endoplasmic reticulum (ER) is correct?

Accepted Answer

The rough ER is studded with ribosomes and is involved in protein synthesis.

Question 16

Which of the following best describes the role of lipopolysaccharide (LPS) in Gram-negative bacteria?

Accepted Answer

LPS is a toxin found in the outer membrane and can trigger strong immune responses in humans.

Question 17

A researcher is studying the process of bacterial conjugation. Which structure is essential for this process?

Accepted Answer

Pilus

Question 18

Which of the following statements about binary fission is correct?

Accepted Answer

Binary fission results in the formation of genetically identical daughter cells.

Question 19

Which of the following is a function of bacterial capsules?

Accepted Answer

Protection against phagocytosis and desiccation

Question 20

Which of the following best explains why algae can be harmful to aquatic ecosystems?

Accepted Answer

Algae produce toxins that can kill fish and other aquatic organisms.

Microbiology Study Guide: Key Concepts and Learning Objectives

Study Guide - Practice Questions

Study Guide - Flashcards