DNA Manipulation & Genetic Technologies: Enzymes, CRISPR, PCR, and GMOs

What is DNA manipulation?

The direct manipulation of an organism's genome using biotechnology to produce organisms with desirable traits.

What are genetically modified organisms (GMOs)?

Organisms whose DNA has been altered through genetic engineering.

What is the role of DNA polymerase?

It synthesizes DNA by adding free nucleotides to a DNA template strand.

What do endonucleases do?

They cut DNA at specific recognition sites of 4-8 base pairs.

What are sticky ends in DNA cutting?

They leave overhanging bases that can bind with complementary sticky ends.

What are blunt ends in DNA cutting?

They cut straight across DNA and can join to any other blunt end fragment.

What is the function of DNA ligase?

It joins DNA fragments together by forming covalent bonds, a process called ligation.

What is CRISPR-Cas9?

A natural defense system used by bacteria to protect against viruses, consisting of CRISPR DNA sequences and the Cas9 enzyme.

How does CRISPR-Cas9 work in bacteria?

Guide RNA binds to a specific DNA sequence, and the Cas9 enzyme cuts the DNA, destroying invading viral DNA.

What is gene knock-in?

A method where a new DNA sequence is inserted to replace faulty genes.

What is gene knock-out?

A method where insertions or deletions disable a gene.

What is the purpose of the Polymerase Chain Reaction (PCR)?

To amplify DNA, producing millions of copies from a small sample.

What are the three steps of PCR?

Denaturation, Annealing, and Extension.

What happens during the denaturation step of PCR?

DNA is heated to 94-98°C, breaking hydrogen bonds and separating strands.

What occurs during the annealing step of PCR?

The temperature is lowered to about 50-65°C, allowing primers to bind to complementary DNA sequences.

What is the role of Taq polymerase in PCR?

It builds new DNA strands during the extension step at 72°C.

What is gel electrophoresis used for?

To separate DNA fragments based on size and charge.

How does DNA move in gel electrophoresis?

DNA moves toward the positive electrode because it is negatively charged.

What indicates DNA from the same individual in DNA profiling?

Matching band patterns.

What are recombinant plasmids?

Small circular DNA molecules in bacteria used as vectors to carry foreign DNA into cells.

What is the process of creating recombinant plasmids?

Cutting plasmid and desired gene with the same restriction enzyme, joining sticky ends, and using DNA ligase.

How is human insulin produced using recombinant DNA technology?

The insulin gene is inserted into a plasmid, introduced into bacteria, which replicate and produce insulin protein.

What are transgenic organisms?

GMOs that contain genes from another species.

What is an example of a herbicide-resistant crop?

Roundup Ready canola, which contains the gox gene from bacteria.

What is an example of a pest-resistant crop?

Bt cotton, which contains bacterial genes producing insecticidal proteins.

What are the benefits of genetic engineering in agriculture?

Reduced insecticide use, increased crop productivity, and improved traits.