Biotechnology Skills (Version A, Version B)

When preparing agar plates for bacterial culture, which of the following is the best next step after streaking the plates with bacteria?

Confirm incubator temperature is correct, then place the plates upside-down inside the incubator

You have just completed streaking out some E. coli on an LB agar plates. Which of the following is the best next step?

Confirm incubator temperature is correct, then place the plates upside-down inside the incubator

Which of the following is the correct method to make 375mL of a 24% (w/v) CaCl2 solution? - dissolve, dH20, adjust

Dissolve the CaCl2 in a small volume of dH20, then adjust the volume to 375 ml

Shaking is not necessary to oxygenate an aerobic liquid culture for optimal growth.

False

Open the lid of the Petri plate just enough to insert the loop Streak across quadrant 1 and into quadrant 2 Flame your loop and let it cool/aseptically open a new disposable loop Streak back and forth to cover quadrant 2

Flame your loop and let it cool/aseptically open a new disposable loop Open the lid of the Petri plate just enough to insert the loop Streak across quadrant 1 and into quadrant 2 Streak back and forth to cover quadrant 2

An SOP requires that the pH of a particular solution be 4.75, however the reading given by the meter is 5.65. Which of the following solutions should the technician use to adjust the pH to 4.75? (HCl, H20, NaOH, or CaCl2)?

HCl

A technician is testing the purity of a DNA sample using a spectrophotometer. He gets a 260 nm reading of 0.51 au, and a 280 nm reading of 0.65 au. Recalling that the preferred range for the value is 1.8-2.0, is the purity of the sample acceptable?

No

Which of the following methods is used to obtain single, isolated bacterial colonies?

Streak plate method

What is the purpose of using the quadrant method when streaking bacteria on agar plates?

To dilute out individual bacterial cells leading to isolated colonies

A technician is asked to determine the size of a PCR product. She runs the PCR product on an agarose gel, but notices the band for the PCR product is well above (i.e., closer to the wells) than any bands on the DNA ladder. Which of the following steps can the technician take to ensure she can determine the size of the PCR product the next time the samples are run?

Use a DNA ladder with larger DNA fragments

When plotting this data on a graph should the concentration (the independent variable) be on the X or the Y axis?

x-axis

When plotting this data on a graph should the absorbance (the dependent variable) be on the X or the Y axis?

y-axis

Assume the DNA in lane 4 in the image below was loaded on the gel after it was digested with the restriction enzyme HindIII. If the DNA was originally linear, and the restriction enzyme digest was complete, how many HindIII sites are in the plasmid?

1

A technician is performing an assay with a 30 minute incubation step. If the technician begins the incubation at 14:42, at what time will the incubation step end?

15:12

Assume the DNA in lane 3 in the image below was loaded on the gel after it was digested with the restriction enzyme EcoRI. If the DNA was originally a plasmid, and the restriction enzyme digest was complete, how many EcoRI sites are in the plasmid?

2

The International Organization for Standardization (ISO) provides a standardized way of writing dates, in order to avoid confusion when communicating globally. The format is: YYYY-MM-DD. Which of the following is the correct way to write May 29, 2023 using the ISO format?

2023-05-29

What is the volume in mL in the graduated cylinder? Record the correct amount.

43

Assume the DNA fragments in lane 4 below are from one plasmid digested with the restriction enzyme HindIII. What is the approximate size in bp of the plasmid?

5000

Referring to the image above, what is the volume in mL in the graduated cylinder? Record the answer to one decimal place below

6.6

Assume the DNA fragments in lane 3 below are from one plasmid digested with the restriction enzyme EcoRI. What is the approximate size in bp of the plasmid?

9500

Which of the following instruments should be used to pipet 175 microliters? (P20, P100, P200, or P1000)?

P200