Q: If the cluster density on a HiSeq flow cell is 800 clusters/mm$$^2$$ and the flow cell has an area of 1000 mm$$^2$$, approximately how many clusters are generated?

$$800 \times 1000 = 800,000$$ clusters

Question 1

Which of the following is a key innovation that enabled the high-throughput capabilities of Illumina Next Generation Sequencing (NGS) technology?

Accepted Answer

Reversible fluorescent terminators and high-resolution photographic detectors

Question 2

A researcher wants to sequence the genomes of 10,000 individuals in a cost-effective and timely manner. Which sequencing platform would be most appropriate based on throughput and cost per genome?

Accepted Answer

Illumina HiSeq X Ten

Question 3

During Illumina NGS, what is the primary purpose of adding adapters to fragmented DNA?

Accepted Answer

To enable attachment of DNA fragments to the flow cell surface

Question 4

Which step in the Illumina sequencing workflow ensures that each DNA fragment is amplified into a cluster for detection?

Accepted Answer

Cluster generation by PCR on the flow cell

Question 5

The cost of sequencing a human genome has dropped dramatically over the past two decades. Which technological advancement most contributed to this trend?

Accepted Answer

Introduction of massively parallel sequencing platforms

Question 6

A patient’s tumor is sequenced using NGS to identify actionable mutations for targeted therapy. This approach is an example of:

Accepted Answer

Precision medicine

Question 7

Which equation best describes the relationship between the number of sequencing cycles ($$n) $$and the maximum read length ($$L) in $$Illumina sequencing?

Accepted Answer

$$L = n$$

Question 8

Why is it important to align NGS reads back to a reference genome during data analysis?

Accepted Answer

To identify sequence variants and mutations relative to the reference

Question 9

A sequencing run on an Illumina HiSeq 4000 produces 1,500 Gb of data. If each human genome requires approximately 100 Gb for adequate coverage, how many genomes can be sequenced in one run?

Accepted Answer

$$\frac{1,500}{100} = 150$$ genomes

Question 10

Which of the following best explains why reversible terminators are essential for Illumina sequencing?

Accepted Answer

They allow controlled, stepwise addition of nucleotides and enable imaging after each cycle

Question 11

A clinical trial uses NGS to stratify cancer patients into groups based on their tumor’s genetic profile. Which advantage does this provide over traditional therapies?

Accepted Answer

Patients receive individualized treatments, improving outcomes

Question 12

Which of the following is NOT a step in the Illumina NGS workflow?

Accepted Answer

Capillary electrophoresis

Question 13

If the cluster density on a HiSeq flow cell is 800 clusters/mm$$^2$$ and the flow cell has an area of 1000 mm$$^2$$, approximately how many clusters are generated?

Accepted Answer

$$800 	imes 1000 = 800,000$$ clusters

Question 14

Which of the following statements about the cost of sequencing the human genome is correct?

Accepted Answer

The cost has decreased faster than predicted by Moore’s Law due to NGS advances

Question 15

Which sequencing method is most suitable for sequencing a single gene in a small number of samples?

Accepted Answer

Sanger sequencing

Question 16

In the context of NGS, what is the main advantage of using a flow cell with multiple lanes?

Accepted Answer

It enables simultaneous sequencing of multiple samples

Question 17

A hospital wants to implement precision medicine for cancer patients. Which step is essential for this approach?

Accepted Answer

Sequencing each patient’s tumor genome to identify actionable mutations

Question 18

Which of the following best describes the principle of 'sequencing by synthesis' used in Illumina NGS?

Accepted Answer

DNA polymerase incorporates fluorescently labeled nucleotides, and each incorporation is detected by imaging

Question 19

A researcher is comparing the throughput of different sequencing platforms. Which equation would they use to calculate the total data output ($$D) if $$the number of reads per run is $$N$$ and the average read length is $$L$$?

Accepted Answer

$$D = N 	imes L$$

Question 20

Which of the following is a real-world application of NGS in healthcare?

Accepted Answer

Identifying genetic variants associated with drug response in patients

DNA Sequencing Technologies and Applications in Genetics

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