Question 1

Which of the following statements best explains why viruses are considered non-living?

Accepted Answer

Viruses lack cellular structure and cannot carry out metabolism on their own.

Question 2

A microbiologist is studying a cell with a nucleus, mitochondria, and linear chromosomes. To which domain does this cell most likely belong?

Accepted Answer

Eukarya

Question 3

Which cellular activity is common to ALL cells, both prokaryotic and eukaryotic?

Accepted Answer

DNA replication

Question 4

A rod-shaped bacterium divides and forms chains. What is the correct term for this arrangement?

Accepted Answer

Streptobacillus

Question 5

Biological nitrogen fixation is essential for life because:

Accepted Answer

It transforms atmospheric $$\mathrm{N_2$}$$ into ammonia usable by living organisms.

Question 6

Which group of organisms is solely responsible for biological nitrogen fixation?

Accepted Answer

Bacteria and Archaea

Question 7

Industrial microbiology includes all of the following EXCEPT:

Accepted Answer

Genetic engineering of crops

Question 8

Which of the following best distinguishes biotechnology from traditional fermentation?

Accepted Answer

Biotechnology involves genetic manipulation, whereas fermentation relies on natural microbial processes.

Question 9

A scientist wants to study unculturable microbes in soil. Which method should they use?

Accepted Answer

Cultivation-independent methods such as metagenomics

Question 10

Which of the following correctly describes the relationship between cell surface area ($$A) $$and volume ($$V) as $$cell size increases?

Accepted Answer

Volume increases faster than surface area: $$A \propto r^2$, V$$ \propto $$r^3$$

Question 11

Which property of microscopy is defined as the ability to distinguish two points as separate entities?

Accepted Answer

Resolution

Question 12

The resolving power ($$d) of a $$microscope is given by $$d = \frac{0.61 \lambda}{n \sin 	heta}. If $$the wavelength ($$\lambda) $$decreases, what happens to the resolving power?

Accepted Answer

Resolving power increases (smaller $$d$$ means better resolution)

Question 13

Which microscopy technique allows visualization of living cells without staining and enhances contrast by amplifying differences in refractive index?

Accepted Answer

Phase-contrast microscopy

Question 14

Which of the following is a major advantage of transmission electron microscopy (TEM) over scanning electron microscopy (SEM)?

Accepted Answer

TEM provides detailed internal structures, while SEM shows surface details.

Question 15

Louis Pasteur's experiments disproved spontaneous generation by showing that:

Accepted Answer

Microbes only appeared when exposed to air, not from sterile broth in swan-neck flasks.

Question 16

Pasteurization, developed by Louis Pasteur, is a process that:

Accepted Answer

Reduces microbial load by heating food to a specific temperature for a set time.

Question 17

Which of the following is the correct order of Koch’s postulates?

Accepted Answer

Find microbe in diseased host, isolate and grow in pure culture, inoculate healthy host, recover microbe from host.

Question 18

Sergei Winogradsky and Martinus Beijerinck contributed to microbiology by:

Accepted Answer

Discovering microbial diversity and metabolic processes in environmental samples.

Question 19

Bacteria have been crucial in advancing molecular biology because:

Accepted Answer

Their simple structure allows easy manipulation and study of genetic material.

Question 20

A patient is diagnosed with a bacterial infection. According to Koch’s postulates, which step must be completed to confirm the causative agent?

Accepted Answer

Grow the suspected bacterium in pure culture and demonstrate it causes disease in a healthy host.

Chapter 1: The Microbial World – Study Guide and Key Concepts

Study Guide - Practice Questions

Study Guide - Flashcards