Question 1

Which type of RNA is used to directly translate the DNA code into making functional proteins?

Accepted Answer

Messenger RNA (mRNA) is the type of RNA that is transcribed from DNA and carries the genetic information out of the nucleus to the ribosome, where it serves as a template for the assembly of amino acids into a functional protein. Transfer RNA (tRNA) and ribosomal RNA (rRNA) have important roles in protein synthesis but do not carry the direct genetic information needed to create proteins. Probe RNA is not a commonly used term and does not relate to the process of translation.

Question 2

In which technique is the signal amplified instead of the actual target DNA?

Accepted Answer

Branched DNA amplification is a technique where the signal is amplified rather than the target DNA itself.

Question 3

What would be an advantage of using molecular diagnostic techniques in identification of specific HLA antigens instead of serological techniques?

Accepted Answer

E

Question 4

What is meant by semi-conservative replication of DNA?

Accepted Answer

Semi-conservative replication of DNA refers to the fact that during DNA replication, each original strand acts as a template for the synthesis of a new complementary strand, resulting in two daughter molecules, each consisting of one original and one newly synthesized strand. This means that each new strand is semi-conserved from the original, as it maintains half of the original molecule. Option A is incorrect because the entire molecule is replicated at one time. Option C is incorrect because both copies are identical. Option D is incorrect because DNA replication is carried out by DNA polymerase, not RNA.

Question 5

In order for a probe to hybridize to the target,which condition must be met?

Accepted Answer

For a probe to hybridize to the target, it must have complementary bases. This means that the sequence of the probe should be complementary to the sequence of the target. The target can be either single-stranded DNA or RNA. However, if the target is double-stranded, it needs to be denatured (i.e., separated into single strands) before the probe can hybridize to it. B and C are incorrect because the target can be single-stranded DNA in addition to RNA, and the target does not have to have the same bases as the probe.

Question 6

Restriction fragment length polymorphisms are characterized by all of the following EXCEPT:

Accepted Answer

Restriction fragment length polymorphisms (RFLPs) are characterized by variations in the length of DNA fragments resulting from the digestion of DNA with restriction enzymes. The variations in fragment length are due to differences in the DNA sequence recognized by the restriction enzyme. Therefore, RFLPs cannot have the same DNA base sequences.

Question 7

In DNA sequencing,what is the purpose of the dideoxynucleotide bases?

Accepted Answer

Dideoxynucleotides (ddNTPs) lack a hydroxyl (OH) group on the 3' carbon of their sugar ring, which is essential for the next nucleotide to be added during DNA synthesis. When incorporated into a growing DNA chain during sequencing, the lack of the OH group on the ddNTPs prevents further elongation of the chain, effectively stopping growth at a specific point. This creates a set of fragments of different lengths, which can be separated by size and read in order to determine the DNA sequence.

Question 8

Restriction endonucleases used in DNA analysis are characterized by all of the following EXCEPT:

Accepted Answer

Restriction endonucleases only cleave DNA, not RNA.

Question 9

A short strand of DNA or RNA used to detect an unknown nucleic acid in a patient specimen best describes a:

Accepted Answer

A nucleic acid probe is a short strand of DNA or RNA that is complementary to the sequence of a specific target nucleic acid. When the probe is labeled with a detectable marker, such as a fluorescent molecule or radioisotope, it can be used to detect the presence of the target nucleic acid in a patient specimen. Restrictions enzymes are used in DNA analysis to cut DNA into smaller fragments, primers are short molecules that are used in PCR to amplify DNA, and restriction fragment length polymorphism is a technique used to analyze genetic variation.

Question 10

A reaction characterized by amplification of a specific region of a DNA strand through denaturing and annealing best describes which of the following?

Accepted Answer

The polymerase chain reaction (PCR) is a commonly used technique for amplifying a specific region of DNA. It involves cycles of denaturation, annealing of primers to the target region, and extension of the primers by DNA polymerase, resulting in the amplification of the target region. Signal amplification, solution hybridization, and ligase chain reaction are all different techniques that do not specifically involve DNA amplification through denaturing and annealing.

Question 11

Which is the correct conclusion if results of DNA restriction analysis by gel electrophoresis show a difference in one band?

Accepted Answer

A difference in one band indicates that there is a variation in the DNA fragments and, therefore, the samples are not identical.

Question 12

Use of microarrays consisting of either DNA or RNA to identify an unknown nucleic acid best describes:

Accepted Answer

Microarrays consisting of DNA or RNA are commonly known as DNA chip technology or gene chips. These chips contain thousands of tiny spots that each contains a known DNA sequence or gene. When an unknown nucleic acid is applied to the chip, any complementary sequences will bind to their respective spots on the chip, allowing researchers to identify the genes present in the sample. This technology is frequently used in gene expression analysis and genotyping.

Question 13

Which of the following steps are included in a Southern blot?

Accepted Answer

The Southern blot technique involves separating DNA fragments by gel electrophoresis, transferring the fragmented DNA from the gel to a membrane, and hybridizing the membrane with a labeled DNA probe to detect the presence or absence of a specific DNA fragment. The other options (A, C, D) refer to different techniques or steps that are not part of the Southern blot.

Quiz 11: Molecular Techniques