Question 1

Which of the following best describes the process of bacterial transformation?

Accepted Answer

The uptake of free DNA from the environment by a bacterium.

Question 2

A student grows E. coli on an agar plate containing ampicillin. Colonies appear. What is the most likely explanation?

Accepted Answer

E. coli has acquired an ampicillin resistance gene, possibly via transformation.

Question 3

Which of the following media is both selective and differential, and what does it select and differentiate for?

Accepted Answer

Mannitol salt agar; selects for salt-tolerant bacteria and differentiates mannitol metabolism.

Question 4

A sample is plated on MacConkey agar. Colonies grow but there is no color change. What can you conclude?

Accepted Answer

The bacteria are Gram-negative and do not ferment lactose.

Question 5

Which of the following statements about catalase is correct?

Accepted Answer

Catalase breaks down hydrogen peroxide, releasing oxygen gas.

Question 6

A patient is diagnosed with strep throat. Which type of microorganism is responsible?

Accepted Answer

Bacteria

Question 7

Which of the following is a protozoan pathogen?

Accepted Answer

Giardia

Question 8

A Gram stain is performed and the cells appear pink under the microscope. What does this indicate about the cell wall structure?

Accepted Answer

Thin peptidoglycan layer and presence of an outer membrane.

Question 9

Which of the following is an example of a sterilization method used in the laboratory?

Accepted Answer

Autoclave

Question 10

A student observes shiny red colonies on an agar plate. Which bacterium is most likely present?

Accepted Answer

Serratia marcescens

Question 11

Which of the following best describes the difference between selective and differential media?

Accepted Answer

Selective media favors certain microbes; differential media distinguishes between microbes based on traits.

Question 12

Why is it important to keep the lid of a Petri dish closed during experiments?

Accepted Answer

To avoid contamination from airborne microbes.

Question 13

Which of the following diseases is caused by a virus?

Accepted Answer

Measles

Question 14

Which of the following statements about the spread of antibiotic resistance is correct?

Accepted Answer

Transformation can spread antibiotic resistance genes among bacteria.

Question 15

Which of the following equations correctly represents the breakdown of hydrogen peroxide by catalase?

Accepted Answer

$$2H_2O_2 \rightarrow 2H_2O + O_2$

Question 16

Which of the following is an example of a fungus studied in Lab 2?

Accepted Answer

Rhizopus

Question 17

A patient is diagnosed with MRSA. What type of microorganism is responsible?

Accepted Answer

Bacteria

Question 18

Which of the following statements about Rogosa agar is correct?

Accepted Answer

It is very acidic.

Question 19

Which of the following diseases is more widespread globally?

Accepted Answer

Influenza

Question 20

A student is asked to predict the outcome of growing bacteria with a plasmid conferring GFP fluorescence and ampicillin resistance on an agar plate containing ampicillin. Which outcome is most likely?

Accepted Answer

Growth with green fluorescence.

Microbiology Study Guide: Genetics, Microbial Growth, Media, and Pathogen Identification

Study Guide - Practice Questions

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