Q: If a bacterial culture has a generation time of 30 minutes, how many cells will be present after 3 hours if you start with 100 cells? Use the formula $$N = N_0$ \times 2^n$$, where $$n is $$the number of generations.

$$N = 100 \times 2^6$ = 6400$$ cells

Question 1

Which of the following best describes why viruses are considered 'acellular' in the biological spectrum?

Accepted Answer

They lack cellular structures such as ribosomes and cytoplasm.

Question 2

Which component is found in all viruses and is essential for protecting their genetic material?

Accepted Answer

Capsid

Question 3

A virus that lacks an envelope is referred to as a:

Accepted Answer

Naked virus

Question 4

Which enzyme is commonly required by RNA viruses for replication within a host cell?

Accepted Answer

Reverse transcriptase

Question 5

During the six-step viral replication cycle, which step involves the viral genome entering the host cell?

Accepted Answer

Penetration

Question 6

What is the primary difference between the lytic and lysogenic cycles of bacteriophages?

Accepted Answer

Lytic cycle results in immediate destruction of the host cell, while lysogenic cycle integrates viral DNA into the host genome.

Question 7

Which of the following best defines 'host range' in virology?

Accepted Answer

The spectrum of host cells a virus can infect.

Question 8

Cytopathic effects (CPE) are observed in cells infected by viruses. Which of the following is an example of a CPE?

Accepted Answer

Cell lysis and formation of syncytia

Question 9

Which of the following statements about prions is correct?

Accepted Answer

Prions are infectious proteins that lack nucleic acids.

Question 10

Which of the following is a macronutrient required in large quantities by microorganisms for cell structure and metabolism?

Accepted Answer

Proteins

Question 11

An organism that uses $$CO_2 as $$its carbon source and derives energy from chemical compounds is classified as a:

Accepted Answer

Chemoautotroph

Question 12

Which transport process requires energy and moves substances against their concentration gradient?

Accepted Answer

Active transport

Question 13

In a hypotonic solution, a bacterial cell without a cell wall will most likely:

Accepted Answer

Lyse due to water influx

Question 14

Which enzyme is responsible for neutralizing superoxide radicals in aerobic bacteria?

Accepted Answer

Superoxide dismutase

Question 15

A facultative anaerobe is best described as an organism that:

Accepted Answer

Can use oxygen but also grow in its absence

Question 16

Which type of symbiotic relationship is illustrated when one organism benefits and the other is neither harmed nor helped?

Accepted Answer

Commensalism

Question 17

Biofilms are significant in medical settings because:

Accepted Answer

They increase microbial resistance to antibiotics and disinfectants.

Question 18

Which phase of the bacterial growth curve is characterized by equal rates of cell division and cell death?

Accepted Answer

Stationary phase

Question 19

If a bacterial culture has a generation time of 30 minutes, how many cells will be present after 3 hours if you start with 100 cells? Use the formula $$N = N_0$ 	imes 2^n$$, where $$n is $$the number of generations.

Accepted Answer

$$N = 100 	imes 2^6$ = 6400$$ cells

Question 20

Which of the following is a correct statement about Shigella infection (shigellosis)?

Accepted Answer

A very small inoculum (10-200 organisms) can cause infection.

Comprehensive Study Notes: Viruses, Microbial Nutrition, and Microbial Growth

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