Question 1

Which feature distinguishes Archaea from Bacteria and Eukarya in terms of membrane composition?

Accepted Answer

Ether-linked lipids

Question 2

A bacterial cell is observed to have a thick peptidoglycan layer, teichoic acids, and stains purple in a Gram stain. Which of the following is TRUE about this cell?

Accepted Answer

It lacks porins

Question 3

Which enzyme is responsible for relieving supercoiling during DNA replication?

Accepted Answer

Topoisomerase

Question 4

During group translocation, a sugar molecule is transported into a bacterial cell and chemically modified. Which molecule donates the phosphate group in this process?

Accepted Answer

PEP (phosphoenolpyruvate)

Question 5

Which of the following statements about the lag phase of bacterial growth is CORRECT?

Accepted Answer

Cells are adapting to new conditions and metabolically active

Question 6

A researcher observes a bacterium moving in a corkscrew fashion. Which structure is most likely responsible for this type of motility?

Accepted Answer

Axial filaments (endoflagella)

Question 7

Which of the following is a feature of Gram-negative bacteria but NOT Gram-positive bacteria?

Accepted Answer

Outer membrane containing Lipid A

Question 8

Which mechanism of horizontal gene transfer requires direct cell-to-cell contact?

Accepted Answer

Conjugation

Question 9

Which of the following statements about DNA polymerase III is CORRECT?

Accepted Answer

It is the main enzyme for DNA synthesis during replication

Question 10

A cell is observed to have 70S ribosomes within its mitochondria. What does this observation most directly support?

Accepted Answer

The endosymbiotic theory

Question 11

Which of the following is TRUE regarding secondary active transport?

Accepted Answer

It uses an ion gradient to drive transport

Question 12

Which adaptation is most likely found in psychrophiles?

Accepted Answer

Increased unsaturated fatty acids in membranes

Question 13

Which statement about biofilms is CORRECT?

Accepted Answer

Biofilms use quorum sensing for communication

Question 14

Which oxygen requirement group is characterized by the presence of both superoxide dismutase and catalase?

Accepted Answer

Obligate aerobe

Question 15

Which of the following statements about Archaea is TRUE?

Accepted Answer

Archaea can perform methanogenesis

Question 16

A Gram-negative bacterium is exposed to antibiotics targeting peptidoglycan. Which feature may help it resist the antibiotic compared to Gram-positive bacteria?

Accepted Answer

Outer membrane

Question 17

Which of the following is a correct match between a motility type and its energy source?

Accepted Answer

Flagellar motility – proton motive force

Question 18

Which phase of bacterial growth is characterized by birth rate equaling death rate?

Accepted Answer

Stationary phase

Question 19

Which of the following is a trigger for quorum sensing in bacteria?

Accepted Answer

High cell density

Question 20

Which enzyme is responsible for joining Okazaki fragments during DNA replication?

Accepted Answer

Ligase

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