Q: Which equation best represents the complementary base pairing between a DNA probe and its target mRNA during in situ hybridization?

$$\text{DNA probe: } 5'\text{-TCAAGGTCTCAG-3'} \text{ pairs with mRNA: } 3'\text{-AGUUCCAGAGUC-5'}$$

Question 1

Which technique allows researchers to visualize the location of specific mRNAs within an intact organism, such as a Drosophila embryo, by using fluorescently labeled probes?

Accepted Answer

In situ hybridization

Question 2

In RT-PCR, what is the role of the enzyme reverse transcriptase?

Accepted Answer

It synthesizes a complementary DNA (cDNA) strand from an mRNA template.

Question 3

A researcher wants to compare gene expression between two tissues using a DNA microarray. If tissue 1 cDNA is labeled red and tissue 2 cDNA is labeled green, what color will a spot appear if a gene is expressed in both tissues?

Accepted Answer

Yellow

Question 4

Which step in RT-PCR ensures that only the coding sequence of a gene is carried forward for analysis, excluding introns?

Accepted Answer

Reverse transcription of mRNA to cDNA

Question 5

Why is RNA sequencing (RNA-seq) considered more powerful than DNA microarray assays for genome-wide expression studies?

Accepted Answer

RNA-seq can measure expression levels over a wider range and does not require prior knowledge of genomic sequences.

Question 6

During PCR amplification in RT-PCR, what determines the size of the amplified DNA fragment?

Accepted Answer

The distance between the primers used

Question 7

Which equation best represents the complementary base pairing between a DNA probe and its target mRNA during in situ hybridization?

Accepted Answer

$$	ext{DNA probe: } 5'	ext{-TCAAGGTCTCAG-3'} 	ext{ pairs with mRNA: } 3'	ext{-AGUUCCAGAGUC-5'}$$

Question 8

A scientist uses RT-PCR to analyze gene expression in six embryonic stages. If the gel shows bands in lanes 2 through 6, what does this indicate?

Accepted Answer

The gene is expressed in stages 2 through 6.

Question 9

Which of the following is NOT a step in the process of RNA sequencing (RNA-seq)?

Accepted Answer

Hybridizing cDNAs to a microarray

Question 10

In a DNA microarray experiment, what does a black spot indicate?

Accepted Answer

The gene is not expressed in either tissue.

Question 11

Which of the following best describes the systems approach in gene expression studies?

Accepted Answer

Investigating networks of gene expression across an entire genome

Question 12

What is the main advantage of quantitative RT-PCR (qRT-PCR) over traditional RT-PCR?

Accepted Answer

qRT-PCR provides quantitative data by measuring fluorescence during PCR.

Question 13

If a gene is expressed only in cancerous tissue and not in normal tissue, what color would you expect its spot to be on a DNA microarray where cancer cDNA is labeled red and normal cDNA is labeled green?

Accepted Answer

Red

Question 14

Which of the following steps is unique to RT-PCR and not found in DNA microarray or RNA-seq protocols?

Accepted Answer

PCR amplification of a specific gene region

Question 15

Which equation represents the process of PCR amplification in RT-PCR?

Accepted Answer

$$	ext{cDNA} + 	ext{primers} ightarrow 	ext{amplified DNA fragments}$$

Question 16

Which technique would be most appropriate for identifying alternatively spliced mRNAs in a tissue sample?

Accepted Answer

RNA sequencing (RNA-seq)

Question 17

What is the primary purpose of using fluorescent tags in gene expression studies?

Accepted Answer

To visualize and distinguish gene expression patterns

Question 18

Which of the following is a real-world application of genome-wide gene expression studies?

Accepted Answer

Comparing gene expression patterns in cancerous and noncancerous tissues to inform treatment protocols

Question 19

Which step in the process of making cDNA from eukaryotic genes involves the use of a primer that binds to the poly-A tail of mRNA?

Accepted Answer

Reverse transcription

Question 20

Which equation best represents the conversion of mRNA to cDNA during reverse transcription?

Accepted Answer

$$	ext{mRNA} + 	ext{reverse transcriptase} ightarrow 	ext{cDNA}$$

Monitoring Gene Expression: Techniques and Applications

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