Question 1

Which of the following best describes the function of the FtsZ protein during bacterial cell division?

Accepted Answer

It forms a ring at the future site of the septum to initiate cell division.

Question 2

A culture of *E. coli* starts with 10 cells and grows exponentially for 2 hours with a generation time of 30 minutes. How many cells will there be at the end of 2 hours? Use $$N = N_0$ 2^n.$$

Accepted Answer

$$N = 10 	imes 2^4$ = 160$$

Question 3

Which phase of the microbial growth curve is characterized by the synthesis of new enzymes but little to no increase in cell number?

Accepted Answer

Lag phase

Question 4

What is the primary role of DNA gyrase in bacterial cells?

Accepted Answer

To introduce negative supercoils into DNA, aiding in compaction and replication

Question 5

Which of the following is a correct description of the S phase in the eukaryotic cell cycle?

Accepted Answer

It is the phase where DNA synthesis occurs.

Question 6

Which enzyme is responsible for forming the phosphodiester bond to seal Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 7

In a chemostat, which two parameters must be controlled to maintain a microbial population in exponential growth?

Accepted Answer

Dilution rate and concentration of limiting nutrients

Question 8

Which of the following best explains why supercoiling is necessary for bacterial chromosomes?

Accepted Answer

Supercoiling compacts the DNA so it fits inside the small bacterial cell.

Question 9

A batch culture of bacteria is in stationary phase. Which of the following best describes the cell population at this stage?

Accepted Answer

The rate of cell division equals the rate of cell death.

Question 10

Which protein helps ensure that the divisome forms at the center of a bacterial cell?

Accepted Answer

Min proteins

Question 11

Which of the following is a function of bactoprenol in bacterial cell wall synthesis?

Accepted Answer

It transports peptidoglycan precursors across the cytoplasmic membrane.

Question 12

Which of the following equations correctly calculates the number of generations ($$n) if $$the generation time ($$g) $$and total time ($$t) $$are known?

Accepted Answer

$$n = \frac{t}{g}$$

Question 13

Which of the following statements about binary fission is correct?

Accepted Answer

It results in two genetically identical daughter cells.

Question 14

Which enzyme is responsible for removing RNA primers and replacing them with DNA during bacterial DNA replication?

Accepted Answer

DNA polymerase I

Question 15

A food product is left at room temperature and bacterial growth enters late exponential phase. What is the most likely consequence?

Accepted Answer

Rapid spoilage due to high bacterial density.

Question 16

Which of the following is a correct description of the role of FtsI proteins in bacterial cell division?

Accepted Answer

They are transpeptidases that insert new peptidoglycan into the expanding cell wall.

Question 17

Which of the following best describes the function of autolysins during bacterial cell wall synthesis?

Accepted Answer

They create small openings in the existing cell wall for insertion of new material.

Question 18

Which of the following is a key difference between batch and continuous cultures?

Accepted Answer

Batch cultures are closed systems, while continuous cultures are open systems.

Question 19

Which of the following is true regarding the packaging of DNA in eukaryotes compared to bacteria?

Accepted Answer

Eukaryotic DNA is wrapped around histone proteins, while bacterial DNA is supercoiled by DNA gyrase.

Question 20

Which of the following best describes the process of transpeptidation in bacterial cell wall synthesis?

Accepted Answer

Formation of peptide bonds between the pentapeptide of a peptidoglycan precursor and the tetrapeptide of an existing unit.

Microbial Growth and Cell Division: Mechanisms and Regulation

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