Gel electrophoresis was developed Question 1 options: in the 1970s in 2018 in th

Question

Gel electrophoresis was developed

Question 1 options:

in the 1970s

in 2018

in the 1580s

in the 1700s

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Question 2 (1 point)

The gel matrix of gel electrophoresis is _____

Question 2 options:

unsaturated fat or oil

an enzyme such as lactase

a gas at room temperature such as carbon dioxide

either a seaweed extract of agarose or polyacrylamide

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Question 3 (1 point)

What property of DNA is the basis for sorting DNA fragments by gel electrophoresis

Question 3 options:

DNA chemical bases vary from individual to individual and are diverse including cellulose and agarose

DNA chemical bases such as fatty acids and glycerol are charged particles

DNA chemical bases A, U, C, G are identical in different individuals

DNA chemical bases A, T, C, G vary from individual to individual

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Question 4 (1 point)

Why don?t all DNA fragments move through the gel at the same rate?

Question 4 options:

they do move through at the same rate

they do not all have bromothymol blue color added for visualization

they do not all have the ability to bond with the sugar in the sugar phosphate backbone of DNA

they do not all have the same shape and size

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Question 5 (1 point)

Why do scientists include a marker when they run a DNA sample?

Question 5 options:

the marker dissolves into ionic particles allowing charge to move more readily through the chamber

the marker contains the dyes bromothymol blue and orange A. It provides the ability to see the gel bands

the marker contains DNA fragments whose base sequences and lengths are unknown. It provides a second experiment to run at the same time

the marker contains DNA fragments whose base sequences and lengths are already known. It provides a basis for comparison to the unknown

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Question 6 (1 point)

DNA moves through the gel matrix when electrical current is applied to gel because it has a negative charge and is attracted to the positive charged pole of the gel matrix gel electrophoresis chamber

Question 6 options:

FALSE

TRUE

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Question 7 (1 point)

What factors affect the rate at which DNA fragments move through the gel?

Question 7 options:

all of these

size of molecule

shape of molecule

charge of molecule

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Question 8 (1 point)

Would you expect DNA pieces of a particular size to move faster or slower in a gel with a higher percent of agarose?

Question 8 options:

not enough information given

same speed

faster

slower

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Question 9 (1 point)

Describe the steps used to analyze a gel once the electrophoresis is complete

Question 9 options:

it is exposed to incandescent light or normal room light and the bands are compared and compared against the controls

it is exposed to fluorescent light, the bands are compared and compared against the controls

it is exposed to fluorescent or room light and the bands are compared

it is exposed to UV light, the bands are compared and compared against the controls.

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Question 10 (1 point)

The DNA ladder provides a reference for the size of the DNA. Why do you think control samples are also usually run?

Question 10 options:

Control samples will look identical to the data results samples

It is important to provide a control for scientific experiment to validate that the data results are distinct from the control results

Control samples provide a starting point for the next hypothesis

Control samples are not run

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in the 1970s

in 2018

in the 1580s

in the 1700s

Explanation / Answer

Ans 1) a) In the 1970s

The use of gel electrophoresis came into existence for the first time in the 1970s and it was used for the separation and proper analysis of the nucleic acids. Later it was used for enzymes and proteins.

Ans 2) either a seaweed extract of agarose or polyacrylamide

The agarose is a polymer that is extracted from the seaweed and can be used as one of the formulation of the gel matrix. Even polyacrlamide gel can be used. Agarose is isolated from Gelidium and Gracilaria which are seaweeds. The polyacrylamide gel is formed with help of chemical reaction which is driven by free radical.

Ans 3) DNA chemical bases vary from individual to individual and are diverse including cellulose and agarose

The DNA is a negatively charged molecule due to the presence of the phosphate group and it remains so at neutral pH. The rate at which the DNA moves in the gel electrophoresis also depends on the type of gel that is used. The large molecules are slowed down and the smaller ones move at a faster rate due to its ability to move through the holes.

Ans 4) they do not all have the same shape and size

This is the biggest reason as every fragment of DNA has different shape and size. Some are heavy fragments and some are light. This is the reason why the fragments move towards the other side at its own pace.

Ans 5) The marker contains DNA fragments whose base sequences and lengths are already known. It provides a basis for comparison to the unknown.

The marker sequence is loaded purposely along with the main sequences of the DNA. They are DNA or RNA fragments of known length which runs along and helps in determining the size of the DNA fragments which is being tested. It is stained with ethidium bromide and other nucleic acids stains which helps in the process of making it visible.

Ans 6) True

The DNA is a negatively charged molecule due to the presence of the phosphate group and with the opposite attracts, as soon as electric current is applied, it tends to start moving towards the positive charge direction.

Ans 7) all of these

The rate at which the DNA molecules move in gel electrophoresis depends on many factors. It depends on the size where the smaller ones move at faster rate and heavier ones at slower speed. The shape is important as some move fast and some slow. The negative molecules move towards the positive at faster rate as compared to less negative ones or positive molecules.

Ans 8) not enough information given

We cannot determine the rate at which DNA pieces of particular size will move in gel until we know about the size of the same. It depends on the size and the shorter fragments move at faster rate and longer one move at slower rate.

Ans 9) it is exposed to UV lights, the bands are compared and compared against the controls

The DNA is stained with Ethidium bromide and hence it is viewed under the UV transilluminator. The UV light leads to excitation of the electrons and makes it release light making it visible. Once the gel run is complete, it is observed under UV light to analyze the band size and compared with the control

Ans 10) It is important to provide a control for scientific experiment to validate that the data results are distinct from the control results

The control is the only variable that is is going to give a positive result during the gel run. This helps in validating that the experiment is done correctly and helps in determining the size of the molecule.

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