Question 1

Which of the following best explains why Pelagibacter ubique is able to exchange nutrients and waste with its environment more efficiently than Escherichia coli?

Accepted Answer

Because its cells are smaller, resulting in a higher surface area-to-volume ratio.

Question 2

The reduction potential ($E_0'$) of a substance reflects its tendency to donate or accept electrons. If the difference in reduction potential ($\Delta E_0'$) between the electron donor and acceptor increases, what is the effect on the change in free energy ($\Delta G_0'$) and the energy released?

Accepted Answer

The greater the $\Delta E_0'$, the greater the change in free energy ($\Delta G_0'$), and the more energy is released.

Question 3

According to the electron tower, which of the following pairs would yield the most energy when used as an electron donor and acceptor in a redox reaction?

Accepted Answer

Fe$^{2+}$/Fe$^{3+}$ and O$_2$/H$_2$O

Question 4

Which of the following statements about non-coding RNAs (ncRNAs) is correct?

Accepted Answer

ncRNAs can regulate gene expression by base pairing directly to mRNA molecules.

Question 5

A mutation in the riboswitch region of an mRNA prevents it from binding its specific metabolite. What is the most likely consequence for gene expression?

Accepted Answer

The gene will be constitutively expressed, regardless of metabolite presence.

Question 6

In the context of attenuation in the tryptophan operon, what happens when tryptophan levels are high in the cell?

Accepted Answer

Transcription is terminated early due to formation of a terminator hairpin.

Question 7

Which of the following best describes the function of the SOS repair system in bacteria?

Accepted Answer

It is a last-resort system that allows DNA replication to proceed past damage, often introducing mutations.

Question 8

Which of the following is true regarding the spatial separation of transcription and translation in prokaryotes and eukaryotes?

Accepted Answer

Transcription and translation are coupled in prokaryotes but separated in eukaryotes.

Question 9

A researcher is using a selective medium to identify a mutant strain of bacteria that cannot synthesize histidine. Which of the following best describes the expected result?

Accepted Answer

The mutant will not grow on minimal medium lacking histidine.

Question 10

Which of the following is a correct statement about the naming conventions in bacterial genetics?

Accepted Answer

The gene is written in italics with three lowercase letters followed by a capital letter, and the phenotype is written with a capital letter and a plus or minus sign.

Question 11

Which of the following mechanisms is NOT a way that small regulatory RNAs (sRNAs) can regulate gene expression?

Accepted Answer

Directly modifying DNA methylation patterns.

Question 12

A mutation in the hisC gene of E. coli results in a strain that cannot synthesize histidine. How would you designate the genotype and phenotype of this strain?

Accepted Answer

Genotype: hisC-; Phenotype: His-

Question 13

Which of the following best describes the relationship between the position of electron donors and acceptors on the electron tower and the amount of energy released?

Accepted Answer

The further apart the donor and acceptor are on the tower, the more energy is released.

Question 14

Which of the following is a real-world application of riboswitches in biotechnology or medicine?

Accepted Answer

Designing antibiotics that target riboswitches to inhibit bacterial gene expression.

Question 15

If a bacterial cell is exposed to a DNA-damaging agent and the SOS system is activated, what is a likely outcome?

Accepted Answer

The cell may survive but accumulate mutations due to error-prone repair.

Question 16

Which of the following statements about binary fission is correct?

Accepted Answer

Binary fission occurs in both prokaryotes and some eukaryotes.

Question 17

A scientist discovers a new non-coding RNA that binds to the ribosome-binding site of an mRNA and blocks translation. What is the most likely function of this RNA?

Accepted Answer

It acts as a small regulatory RNA (sRNA) to inhibit translation.

Question 18

Which of the following best describes attenuation as a regulatory mechanism?

Accepted Answer

It is a process where translation regulates transcription by forming alternative mRNA structures.

Chapter 7 & 9

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