Q: Which equation correctly represents substrate-level phosphorylation during glycolysis?

$$\text{ADP} + \text{P}_i \rightarrow \text{ATP}$$

Q: Which of the following is the correct formula to calculate the concentration per ml in the original culture broth if 42 colonies grew on the plate after a $$\frac{1}{10}$$ dilution?

$$42 \times 10 = 420$$ cells/ml

Question 1

Which of the following best describes the function of enzymes in cellular metabolism?

Accepted Answer

Enzymes lower the activation energy of biochemical reactions, thereby increasing the rate of metabolic processes.

Question 2

A microbiology student sets up two cultures of Saccharomyces in glucose broth, one with O$$_2$$ and one without. Which statement correctly explains the difference in ATP production and end products between the two cultures?

Accepted Answer

The culture with O$$_2$$ will produce more ATP via aerobic respiration, resulting in CO$$_2$$ and H$$_2O$$, while the culture without O$$_2$$ will produce less ATP via fermentation, resulting in ethanol and CO$$_2.$$

Question 3

Which equation correctly represents substrate-level phosphorylation during glycolysis?

Accepted Answer

$$	ext{ADP} + 	ext{P}_i ightarrow 	ext{ATP}$$

Question 4

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

Accepted Answer

On the plasma (cell) membrane

Question 5

Which of the following best describes chemiosmosis in eukaryotic cells?

Accepted Answer

The movement of protons across the inner mitochondrial membrane, generating ATP via ATP synthase.

Question 6

What happens to the carbons from glucose during aerobic respiration?

Accepted Answer

They are released as CO$$_2$$ during the Krebs cycle and pyruvate oxidation.

Question 7

Which category best describes human pathogens based on their energy and carbon requirements?

Accepted Answer

Heterotrophs

Question 8

A bacterium that grows best at 37°C, is Gram-negative, and requires enriched media is most likely classified as:

Accepted Answer

Mesophile

Question 9

If Sally transferred 15 Staphylococcus aureus cells to her sandwich at 8 AM and ate it at 12 PM, with a generation time of 20 minutes, how many cells were present at lunchtime?

Accepted Answer

245,760 cells

Question 10

Which type of media would you use to selectively grow a bacterium that lives in the ocean?

Accepted Answer

A medium with high salt concentration (halophilic selective medium)

Question 11

Which of the following best describes a biofilm?

Accepted Answer

A complex community of microorganisms attached to a surface and embedded in a self-produced matrix.

Question 12

What is the dilution factor if you transfer 1 ml of culture broth to 9 ml of sterile broth, then plate 1 ml from the resulting 10 ml?

Accepted Answer

$$\frac{1}{10}$$

Question 13

Which of the following is the correct formula to calculate the concentration per ml in the original culture broth if 42 colonies grew on the plate after a $$\frac{1}{10}$$ dilution?

Accepted Answer

$$42 	imes 10 = 420$$ cells/ml

Question 14

Which of the following statements best explains why Mycobacterium is harder to kill with disinfectants than most microbes?

Accepted Answer

It has a waxy, lipid-rich cell wall (mycolic acids) that resists penetration by chemicals.

Question 15

Which of the following best describes the difference between sterilization and disinfection?

Accepted Answer

Sterilization destroys all forms of microbial life, including spores; disinfection reduces the number of pathogenic organisms but may not kill spores.

Question 16

Which of the following is NOT a factor to consider when choosing a disinfectant?

Accepted Answer

The color of the disinfectant

Question 17

Which of the following correctly matches the term with its definition and example?

Accepted Answer

Antisepsis: Reduction of microbial load on living tissue; used for handwashing with alcohol-based gels.

Question 18

Which of the following best describes the structure and function of DNA compared to RNA?

Accepted Answer

DNA is double-stranded, contains deoxyribose, and stores genetic information; RNA is single-stranded, contains ribose, and is involved in protein synthesis.

Question 19

Which of the following is a correct description of the process of transcription?

Accepted Answer

The synthesis of mRNA from a DNA template by RNA polymerase.

Question 20

Which of the following is NOT a method by which DNA can be transferred from one bacterial cell to another?

Accepted Answer

Translation

Microbiology Exam II Study Guide – Step-by-Step Guidance

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