Question 1

Agarose gel electrophoresis allows the separation of DNA based upon .&#10;A)charge&#10;B)base composition&#10;C)size&#10;D)pH

Accepted Answer

Agarose gel electrophoresis separates DNA molecules based on their size. The smaller DNA molecules move through the gel more quickly, while the larger ones move more slowly. Charge and pH do not have a significant effect on the separation, and while base composition can affect the size of the DNA molecule, it is not the primary factor in separation on the gel.

Question 2

Which of the following fragments of DNA would migrate closest to the wells during agarose gel electrophoresis?&#10;A)1000 bp&#10;B)150 bp&#10;C)10,000 bp&#10;D)650 bp

Accepted Answer

C

Question 3

FISH allows DNA or RNA to be visualized in its natural location.

Accepted Answer

FISH (Fluorescence in situ hybridization) is a technique that uses fluorescent probes to bind to specific DNA or RNA sequences in a sample, allowing visualization of the genetic material in its natural location.

Question 4

Which statement is not true regarding peptide nucleic acids?&#10;A)Peptide nucleic acids are not degraded by nucleases or proteases.&#10;B)Peptide nucleic acids consist of a polypeptide backbone to which nucleic acid bases are attached as side chains.&#10;C)Peptide nucleic acids are able to bind to complementary strands of DNA or RNA.&#10;D)Peptide nucleic acid penetrates cells easily,and therefore has importance in medicine.

Accepted Answer

Peptide nucleic acids do not penetrate cells easily; they often require delivery systems to enter cells, which limits their direct application in medicine.

Question 5

Which type of hybridization technique would you use to detect the presence of a specific transcript within a culture of bacterial cells grown under specific growth conditions.&#10;A)Eastern blot&#10;B)Western blot&#10;C)Northern blot&#10;D)Southern blot

Accepted Answer

Northern blot is used to detect the presence and abundance of a specific RNA transcript in a sample. In this case, the aim is to detect a specific transcript in a culture of bacterial cells grown under specific growth conditions. Hence, Northern blot would be the appropriate choice for this purpose.

Question 6

What types of labels are added to probes to enable detection during hybridization experiments?&#10;A)fluorescence&#10;B)chemical&#10;C)radioactive&#10;D)all of the above

Accepted Answer

Probes can be labeled with fluorescence, chemicals, or radioactivity to enable detection during hybridization experiments. Therefore, all of the above choices are correct.

Question 7

GC base pairs absorb more ultraviolet light than AT base pairs.

Accepted Answer

This is because GC base pairs have three hydrogen bonds, while AT base pairs only have two. The extra hydrogen bond in GC makes it more stable and thus absorb more ultraviolet light.

Question 8

By what technique can individual DNA molecules be visualized?&#10;A)electron microscopy and metal shadowing&#10;B)light microscopy only&#10;C)agarose gel electrophoresis&#10;D)Northern blot

Accepted Answer

Individual DNA molecules can be visualized with the help of electron microscopy and metal shadowing, where the DNA molecule is coated with a thin layer of metal and then viewed under an electron microscope. Light microscopy only allows visualization of larger structures and is not suitable for visualizing individual DNA molecules. Agarose gel electrophoresis can be used to separate DNA fragments based on their size, but does not visualize individual DNA molecules. Northern blot is a technique used to detect specific RNA molecules in a mixture, and is not used for visualizing DNA molecules.

Question 9

At which wavelength do the bases of DNA and RNA nucleotides absorb the most light?&#10;A)200 nm&#10;B)260 nm&#10;C)280 nm&#10;D)300 nm

Accepted Answer

The nitrogen-containing bases of DNA and RNA (adenine, guanine, cytosine, and thymine/uracil) have a characteristic absorption peak at 260 nm due to the presence of double bonds in their ring structures. This is known as the nucleic acid absorption peak and is commonly used to quantify nucleic acid concentration in biochemical assays. Therefore, wavelength 260 nm is the best choice where the bases of DNA and RNA nucleotides absorb the most light.

Question 10

Which type of blotting uses antibodies to detect proteins on a membrane?&#10;A)Southern blot&#10;B)Northern blot&#10;C)Western blot&#10;D)South-Western blot

Accepted Answer

The Western blotting technique uses antibodies to detect specific proteins that have been transferred onto a membrane from a gel. The Southern blotting technique is used to detect specific DNA fragments, the Northern blotting technique is used to detect specific RNA fragments, and the South-Western blotting technique is used to detect DNA-protein interactions.

Question 11

An A260/A280 ratio of less than 1.8 indicates .&#10;A)pure DNA&#10;B)pure RNA&#10;C)protein contamination of DNA&#10;D)RNA contamination of DNA

Accepted Answer

The answer of An A260/A280 ratio of less than 1.8...

Deck 5: Manipulation of Nucleic Acids