Question 1

Which of the following best describes the role of restriction enzymes in recombinant DNA technology?

Accepted Answer

They cut DNA at specific sequences, allowing scientists to isolate and manipulate genes.

Question 2

A scientist wants to amplify a specific DNA segment from a small blood sample. Which technique should they use, and what is the key temperature step involved?

Accepted Answer

Polymerase chain reaction (PCR); heating to $$95^{\circ}C$ to denature DNA

Question 3

During PCR, what is the function of DNA primers?

Accepted Answer

They bind to target DNA sequences to initiate DNA synthesis by DNA polymerase.

Question 4

If a restriction enzyme recognizes the sequence $$5'	ext{-}GAATTC	ext{-}3'$$ and cuts between G and A, what would be the resulting ends called?

Accepted Answer

Sticky ends

Question 5

Which of the following is a real-world application of DNA microarrays?

Accepted Answer

Comparing gene expression patterns in cancerous and normal cells

Question 6

A patient is suspected to have cystic fibrosis, a disease caused by a single gene mutation. Which DNA technology would be most appropriate for confirming the diagnosis?

Accepted Answer

PCR amplification of the gene followed by DNA sequencing

Question 7

In gel electrophoresis, DNA fragments are separated based on which property?

Accepted Answer

Their length (number of base pairs)

Question 8

Which of the following best explains why genetically modified (GM) crops may pose environmental risks?

Accepted Answer

Genes from GM crops may spread to wild relatives, potentially creating herbicide-resistant weeds.

Question 9

A forensic scientist analyzes DNA from a crime scene using short tandem repeats (STRs). Why is this method effective for individual identification?

Accepted Answer

STRs vary greatly among individuals, providing a unique genetic fingerprint.

Question 10

Which equation correctly represents the number of DNA copies produced after $$n$$ rounds of PCR, starting with a single DNA molecule?

Accepted Answer

$$2^n$$

Question 11

A scientist uses a plasmid to introduce a gene for antibiotic resistance into bacteria. What is the term for this process?

Accepted Answer

Transformation

Question 12

Which of the following is a potential ethical concern associated with gene therapy in humans?

Accepted Answer

Gene therapy may unintentionally alter germline cells, affecting future generations.

Question 13

A researcher wants to distinguish between two alleles of a gene that differ by only one base pair. Which technique would be most effective?

Accepted Answer

Restriction fragment length polymorphism (RFLP) analysis

Question 14

Which of the following statements about Southern blotting is correct?

Accepted Answer

It combines gel electrophoresis with DNA hybridization to detect specific DNA sequences.

Question 15

Why is Taq polymerase used in PCR instead of human DNA polymerase?

Accepted Answer

Taq polymerase is stable at high temperatures required for DNA denaturation.

Question 16

Which of the following is a direct medical application of recombinant DNA technology?

Accepted Answer

Producing human insulin in bacteria for diabetes treatment

Question 17

A farmer wants to grow crops resistant to herbicides. Which genetic engineering strategy would be most effective?

Accepted Answer

Insert a gene encoding herbicide resistance into the crop's genome using a plasmid vector.

Question 18

Which of the following best describes the concept of 'sticky ends' in DNA cloning?

Accepted Answer

Single-stranded overhangs created by restriction enzymes that facilitate the joining of DNA fragments.

Question 19

A geneticist uses DNA technology to identify carriers of sickle cell anemia in a population. Which method would be most appropriate?

Accepted Answer

PCR amplification followed by RFLP analysis of the beta-globin gene

Question 20

Which of the following is a reason why scientists use plasmids in genetic engineering?

Accepted Answer

Plasmids can replicate independently in bacteria, allowing for mass production of recombinant genes.

DNA Technology and Its Applications: Study Notes for General Biology

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