Question 1

Which step in the strawberry DNA extraction protocol is primarily responsible for breaking open the cell and nuclear membranes to release DNA?

Accepted Answer

Adding dish soap (detergent) to dissolve phospholipid bilayers

Question 2

During centrifugation in DNA extraction, what is the purpose of balancing the centrifuge tubes?

Accepted Answer

To prevent the centrifuge from vibrating excessively and potentially damaging the equipment

Question 3

In microbial metabolism, which type of reaction is described as exergonic and hydrolytic, and what is its primary function?

Accepted Answer

Catabolism; breaking down molecules to release energy

Question 4

Which of the following best describes the role of salt (NaCl) in the strawberry DNA extraction process?

Accepted Answer

It neutralizes the negative charge of DNA, allowing strands to clump together

Question 5

Which of the following statements about enzymes is correct?

Accepted Answer

Enzymes lower the activation energy of reactions without being altered themselves

Question 6

A student streaks a plate but observes no isolated colonies after incubation. Which common error most likely caused this result?

Accepted Answer

Not flaming the loop between streaks, resulting in too many cells in each section

Question 7

Which of the following best defines a supernatant in a centrifugation process?

Accepted Answer

The liquid above the pellet after centrifugation

Question 8

Which factor does NOT directly affect enzyme activity in microbial metabolism?

Accepted Answer

Cell wall thickness

Question 9

In the central dogma of molecular biology, which step is analyzed by 'transcriptomics'?

Accepted Answer

Transcription

Question 10

A mutation occurs during transcription. Which subsequent process is most likely to be affected?

Accepted Answer

Translation

Question 11

Which of the following best describes a repressible operon?

Accepted Answer

It is usually on but can be turned off when a specific molecule is present

Question 12

Which process is an example of horizontal gene transfer in bacteria?

Accepted Answer

Conjugation

Question 13

What is the primary difference between conjugative plasmids and R factor plasmids?

Accepted Answer

Conjugative plasmids carry genes for transfer between cells, while R factors carry antibiotic resistance genes

Question 14

Which of the following is a pro of transposons in microbial genetics?

Accepted Answer

They can facilitate genetic diversity and adaptation

Question 15

In Griffith's experiment, what was the key finding regarding transformation?

Accepted Answer

Live non-virulent bacteria acquired virulence from heat-killed virulent bacteria

Question 16

Which phase of a bacteriophage life cycle results in immediate destruction of the host cell?

Accepted Answer

Lytic phase

Question 17

Which method is commonly used to insert foreign DNA into cells by creating temporary pores in the cell membrane using an electric field?

Accepted Answer

Electroporation

Question 18

During PCR, what is the purpose of the heating step?

Accepted Answer

To denature the DNA strands, separating them

Question 19

Which equation best represents the energy change in an exergonic catabolic reaction?

Accepted Answer

$$\Delta G \u003c 0$$

Question 20

A researcher wants to amplify a specific DNA sequence for cloning. Which technique should they use, and what is the main principle behind it?

Accepted Answer

PCR; repeated cycles of heating and cooling to denature, anneal, and extend DNA

Microbiology Lab Concepts and Core Topics: Metabolism, Genetics, and Biotechnology

Study Guide - Practice Questions