BCBIO23-LAB CA

The cells synthesize RNA, growth factors and other molecules required for cell division.

• Lag Phase

• Log Phase

• Stationary Phase

• Death Phase

This phase is marked by the doubling of the bacterial cells.

• Lag Phase

• Log Phase

• Stationary Phase

• Death Phase

The cell population remains constant at this stage. Plotting this phase on the graph gives a smooth horizontal linear line.

• Lag Phase

• Log Phase

• Stationary Phase

• Death Phase

This is the last phase of the bacterial growth.

• Lag Phase

• Log Phase

• Stationary Phase

• Death Phase

What is the typical wavelength used to measure bacterial growth in a spectrophotometer?

• 200 nm

• 260 nm

• 600 nm

• 800 nm

The Kirby-Bauer method is used to assess antibiotic sensitivity. What is the key indicator of antibiotic effectiveness?

• Zone of inhibition

• Increase in colony count

• Change in color of the agar plate

• pH variation

Why is it important to use a control plate when testing antibiotic sensitivity?

• To ensure uniform bacterial growth

• To check for contamination

• To compare growth in the absence of antibiotics

• All of the above

What is the role of ethidium bromide in agarose gel electrophoresis?

• To break down DNA

• To stain DNA for visualization under UV light

• To increase the migration speed of DNA

• To degrade proteins

Why is loading dye added to DNA samples before running gel electrophoresis?

• To increase the density of the sample

• To visualize DNA bands

• To enhance DNA degradation

• To cut DNA into smaller fragments

If two bands appear for the same plasmid DNA sample after gel electrophoresis, what does it indicate?

• Presence of RNA contamination

• Degradation of DNA

• Different conformations of plasmid DNA (supercoiled and relaxed)

• Presence of genomic DNA contamination