Question 1

Which of the following best describes the process of gene cloning using recombinant plasmids?

Accepted Answer

A gene of interest is inserted into a bacterial plasmid, which is then introduced into bacteria. As the bacteria multiply, the gene and its protein product are replicated and harvested.

Question 2

Restriction enzymes are used in DNA technology to cut DNA at specific sequences. What is the significance of 'sticky ends' produced by these enzymes?

Accepted Answer

Sticky ends allow complementary base pairing between DNA fragments, facilitating the joining of fragments from different sources by DNA ligase.

Question 3

A nucleic acid probe is used to identify a specific gene in a bacterial clone. Which property of the probe enables this identification?

Accepted Answer

The probe is a short, single-stranded, labeled DNA molecule that binds to its complementary sequence by base pairing.

Question 4

Reverse transcriptase is critical for producing complementary DNA (cDNA) from mRNA. Why is this viral enzyme necessary?

Accepted Answer

Reverse transcriptase synthesizes DNA from an RNA template, allowing researchers to clone genes that are actively transcribed.

Question 5

How does the CRISPR-Cas9 system differ from traditional gene cloning techniques?

Accepted Answer

CRISPR-Cas9 allows targeted editing or removal of specific genes in living cells, while gene cloning involves copying and expressing genes in recombinant organisms.

Question 6

Why can't all human proteins be synthesized in E. coli?

Accepted Answer

Some human proteins require post-translational modifications that E. coli cannot perform, such as glycosylation.

Question 7

What is the primary advantage of using genetic engineering to produce insulin and human growth hormone?

Accepted Answer

Genetic engineering allows for large-scale, consistent, and safe production of these proteins without relying on animal sources.

Question 8

A transgenic organism is best defined as:

Accepted Answer

An organism that has acquired one or more genes from another species by artificial means.

Question 9

Why is it often necessary to run both human and animal studies to learn about human health risks associated with GMOs?

Accepted Answer

Animal studies provide preliminary safety data, but human studies are needed to confirm effects due to species-specific differences.

Question 10

Bone marrow is considered a good target for gene therapy because:

Accepted Answer

Bone marrow cells can give rise to many types of blood cells, allowing the therapeutic gene to be distributed throughout the body.

Question 11

Which step is NOT part of the basic process of DNA profiling in forensic investigations?

Accepted Answer

Direct sequencing of the entire genome of each suspect.

Question 12

The polymerase chain reaction (PCR) amplifies only a specific region of DNA because:

Accepted Answer

Primers are designed to flank the desired sequence, ensuring only that region is copied.

Question 13

During gel electrophoresis, what causes DNA molecules to move toward the positive pole, and why do larger molecules move more slowly?

Accepted Answer

DNA is negatively charged due to its phosphate backbone, and larger molecules experience more resistance moving through the gel matrix.

Question 14

Short tandem repeats (STRs) are used in DNA profiling because:

Accepted Answer

STRs are highly variable between individuals, allowing for unique identification.

Question 15

DNA profiling can be valuable for determining innocence as well as guilt because:

Accepted Answer

It can show that a suspect's DNA does not match evidence from a crime scene, exonerating the individual.

Question 16

Which equation best represents the exponential amplification of DNA during PCR, where $$n is $$the number of cycles?

Accepted Answer

$$2^n$$

Question 17

Next- and third-generation sequencing machines are used to determine DNA sequences. Why is third-generation sequencing potentially more efficient?

Accepted Answer

It can sequence single DNA molecules in real time, reducing the need for amplification and speeding up the process.

Question 18

The Human Genome Project revealed that most of the human genome does NOT consist of genes. What is the significance of noncoding DNA?

Accepted Answer

Noncoding DNA may have regulatory, structural, or unknown functions and includes repetitive sequences.

Question 19

What is the primary advantage of the whole-genome shotgun method for sequencing genomes?

Accepted Answer

It allows rapid sequencing and assembly of many small DNA fragments simultaneously.

Question 20

How can cross-species comparisons of nucleotide sequences provide insight into evolution?

Accepted Answer

They reveal similarities and differences in genes, helping to infer evolutionary relationships and common ancestry.

DNA Technology and Genomics: Concepts, Methods, and Applications

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