Question

Using the PCR Thermocycler, the DNA sample was heated to what temperature?

Group of answer choices

99 Degrees Celsius

90 Degrees Celsius

95 Degrees Celsius

88 Degrees Celsius

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Question 21 pts

We also used the microcentrifuge to spin our sample of cheek cells. Why is it important to balance the microcentrifuge?

Group of answer choices

Running a centrifuge with unbalanced load could permanently damage the centrifuge. It could also cause injury to you or someone else.

Perfect symmetry of the samples

If it isn't balanced, our sample is ruined

We could lose sample through the cap if it isn't balanced

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Question 31 pts

Why did Daisy swirl the 0.9% saline solution in her mouth for a full 30 seconds before expelling back into the cup?

Group of answer choices

To obtain as many cheek cells as possible

To kill any bacteria that could contaminate our sample

That is just how long she wanted to

That is how long the directions say

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Question 41 pts

After we microcentrifuge the sample for 1 minute, we can visibly see a small white pellet at the bottom of the tube with supernatant (liquid) above. What is that pellet?

Group of answer choices

Cheek Cells

Excess Saline

Food Particles from Mouth

Can't fool me, there was no pellet

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Question 51 pts

Daisy then removed the supernatant and resuspended the cell pellet in a new tube containing 30 uL of saline. She then added 200 uL of 5% Chelex. Why is the Chelex important?

Group of answer choices

After the cells are lysed, Chelex binds to cell materials like ions and molecules which might interfere with DNA. This allow the DNA to be extracted.

Chelex helps visualize our DNA

Chelex adds weight to the tube which helps keep the Microcentrifuge balanced

It helps stabalize the temperature in the Thermocycler

Answer 1

Using the PCR thermocycler, the DNA was heated to what temperature?

Polymerase chain reaction (PCR) is a molecular biology technique invented by Kary Mullis. The three basic steps of PCR is-denaturation, annealing, and extension. The first step is denaturation where the DNA sample is heated. The temperature of this step is 94 to 95-degree Celcius. In this step, the ds DNA separates into individual ss DNA. This step is crucial for the annealing of primers to each such ss DNA and further extension of it.

ANSWER-95 degree Celcius.

We also used the microcentrifuge to spin our sample of cheek cells. Why is it important to balance the microcentrifuge?

As stated the cheek cells were centrifuged in a microcentrifuge. It is important to balance the microcentrifuge because otherwise it can cause pressure in the rotor and damage it. It not only damages the machine but it also can harm the individual operating it.

ANSWER-Running a centrifuge with unbalanced load could permanently damage the centrifuge. It could also cause injury to you or someone else.

Why did Daisy swirl the 0.9% saline solution in her mouth for a full 30 seconds before expelling back into the cup?

Saline water rinse allows killing the bacteria present in the mouth. It improves oral health overall.

ANSWER-To kill any bacteria that could contaminate our sample

After we microcentrifuge the sample for 1 minute, we can visibly see a small white pellet at the bottom of the tube with supernatant (liquid) above. What is that pellet?

Centrifugation follows the principle of sedimentation. As the centrifuge rotates at a given speed the substance with higher density settles down and forms the pellet. The substance with lesser density floats above the pellet forming the supernatant. In this question, the correct answer is food particles from the mouth.

ANSWER-Food particles from the mouth.

Daisy then removed the supernatant and resuspended the cell pellet in a new tube containing 30 uL of saline. She then added 200 uL of 5% Chelex. Why is the Chelex important?

Chelex is a chelating material. It has been made by Bio-Rad. Its function is to purify compounds with the help of ion exchange

ANSWER-After the cells are lysed, Chelex binds to cell materials like ions and molecules which might interfere with DNA. This allows the DNA to be extracted.