Question 1

Dideoxy nucleotides are missing a 3' hydroxyl.

Accepted Answer

Dideoxy nucleotides are modified nucleotides that lack a -OH group at position 3' of the sugar moiety, which makes them unable to form a phosphodiester bond with another nucleotide during DNA synthesis. This property is exploited in Sanger sequencing, where dideoxy nucleotides are used to terminate DNA elongation and generate a ladder of fragments of varying length that can be read to determine the sequence of the original DNA template.

Question 2

Which of the following is a method for detecting the addition of nucleotides in a sequencing reaction?&#10;A)luminescence&#10;B)fluorescence&#10;C)changes in pH&#10;D)all of the above

Accepted Answer

Luminescence, fluorescence, and changes in pH can all be used to detect the addition of nucleotides in a sequencing reaction. Therefore, the best choice is D, all of the above.

Question 3

Which sequencing method would work best for determining the sequence of a single DNA molecule?&#10;A)pyrosequencing&#10;B)third generation sequencing&#10;C)second generation sequencing&#10;D)chain termination sequencing

Accepted Answer

Third generation sequencing methods, such as single-molecule real-time sequencing (SMRT), can directly determine the sequence of a single DNA molecule without the need for amplification or fragmentation. This allows for longer read lengths and fewer errors compared to other sequencing methods.

Question 4

Nanopore technology is speedy and handles long DNA molecules.

Accepted Answer

Nanopore technology is known for its ability to rapidly sequence long DNA molecules in real time. It works by passing a DNA molecule through a nanopore, which generates electrical signals that are read by a sensor and decoded into sequence data. Compared to other sequencing methods, nanopore technology has the advantages of speed, portability, and the ability to generate long-read data.

Question 5

All of the following are second generation sequencing methods except .&#10;A)454 sequencing&#10;B)Illumina/Solexa sequencing&#10;C)SOLiD/Applied Biosystems method&#10;D)Pyrosequencing

Accepted Answer

Pyrosequencing is a first-generation sequencing method, which was one of the earliest types of sequencing technology. The other options listed are all second-generation sequencing methods.

Question 6

When DNA polymerase inserts a dideoxy nucleotide,.&#10;A)chain elongation continues until the end of the template&#10;B)energy is produced during the reaction&#10;C)chain elongation is terminated&#10;D)a primer is formed for the next round of sequencing

Accepted Answer

The insertion of a dideoxy nucleotide terminates chain elongation because the dideoxy nucleotide lacks the 3'-OH group required for the formation of a phosphodiester bond with the next incoming nucleotide. Therefore, the growing chain cannot be extended and the process is halted. This is the basis of the Sanger sequencing method.

Question 7

Nanopore detectors contain pores that only allow to pass through.&#10;A)hydrogen ions&#10;B)single-stranded DNA&#10;C)double-stranded DNA&#10;D)dideoxy nucleotides

Accepted Answer

Nanopore detectors are used to sequence DNA and RNA by passing them through small pores. These pores only allow single-stranded DNA or RNA to pass through. Hydrogen ions and dideoxy nucleotides are not used in sequencing with nanopore detectors. Double-stranded DNA must be denatured into single strands before passing through the pore.

Question 8

DNA chip technology relies on the hybridization of .&#10;A)DNA to DNA&#10;B)DNA to RNA&#10;C)RNA to DNA&#10;D)RNA to RNA

Accepted Answer

DNA chip technology is based on the hybridization of DNA strands with complementary nucleotide sequences. This allows for the detection and analysis of specific genes or genetic variations. Hybridization between RNA and DNA is also possible, but not commonly used in DNA chip technology. Therefore, choice A is the best answer.

Question 9

Which method is most useful for sequencing short DNA regions from multiple individuals?&#10;A)dideoxy sequencing&#10;B)pyrosequencing&#10;C)primer walking&#10;D)SMRT sequencing

Accepted Answer

Pyrosequencing is a rapid and cost-effective method for sequencing short DNA fragments from multiple individuals. It uses pyrophosphate released during DNA synthesis to generate light, and the intensity of the light is proportional to the number of nucleotides incorporated. This method can sequence thousands of DNA fragments in parallel and is suitable for identifying single-nucleotide polymorphisms (SNPs) and mutations. Dideoxy sequencing is laborious and time-consuming, primer walking is limited in the size of the region that can be sequenced, and SMRT sequencing is expensive and prone to errors.

Question 10

DNA moves across nanopore detectors because .&#10;A)an electrical charge is applied&#10;B)there is a high concentration of salt on one side of the channel&#10;C)there is a difference in pH across the membrane&#10;D)it is physically pulled across by enzymes

Accepted Answer

Nanopore detectors work by applying an electrical charge across a tiny pore, and as DNA moves through it, it causes changes in electrical current which can be measured to determine the sequence of the DNA molecule. Therefore, the movement of DNA across the nanopore detector is due to the electrical charge applied.

Deck 8: DNA Sequencing