Extension: 5. What is meant by recombinant DNA technology? 6. Why are bacteria i

ID: 260207 • Letter: E

Question

Extension: 5. What is meant by recombinant DNA technology? 6. Why are bacteria ideal workhorse for biotechnology? 7. What are plasmids? BAC? YAC? 8. What is a vector? 9. Write a short paragraph to compare BAC to YAC (must include similarities a differences) 10. How do biotechnologist make used of restriction enzymes? 11. How can transformed that carry genes of interest be identified and isolat from majority of non-transformed bacteria? 12. List and explain some advantages and uses of the PCR technique 16 What are the three basic steps of conventional PCR? a. Denature, anneal, & strand displacement

Explanation / Answer

5) Recombinant DNA technology – It’s a technique used to combine DNA from different species, and introduced into a host organism. This gets incorporated into the genome of the host organism which results in changes in the organism. The new DNA formed by the combination is called the recombinant DNA.

6) Why are bacteria ideal workhorses for biotechnology?

Bacterial DNA is simple compared to eukaryotic organisms. Bacteria reproduce and multiply very easily.

7) What are plasmids? BAC? YAC?

Plasmids - They are small, circular, double stranded DNA. They naturally occur in bacteria, carry genes and replicate independently from chromosomal DNA. In experiments, plasmids are used for cloning.

BAC – Bacterial artificial chromosome are DNA constructs used for transforming and cloning in bacteria. It’s based on functional fertility plasmid. These are usually used to sequence genome of organisms.

YAC – Yeast artificial chromosomes are genetically engineered chromosomes derived from yeast DNA. These help cloning for DNA fragments of larger size as compared with the DNA that can be cloned using BAC.

8) Vector – It’s a DNA molecule used to carry foreign genetic material into another cell. In this cell, it multiplies and expresses. Plasmid is a type of vector.

9) Compare BAC and YAC

YAC

BAC

Inserts can be large sized (1000-2000kb)

Inserts can be of 200-300kb size

Unstable

Stable

Often chimeric

Rarely chimeric

Difficult to purify

Can be purified intact

10) How do biologists use restriction enzymes?

Restriction enzymes have the ability to identify specific sequences in the DNA and cut/digest at these sites. This property of the restriction enzymes makes them significant in genetic engineering. It can be used to map genomes.

11) How can transformed bacteria that carry gene of interest be identified and isolated from majority of non transformed bacteria?

Transformed bacteria that contain the gene in the plasmid will carry a gene conferring resistance to some antibiotic. So, these bacteria will grow on media that contain this particular antibiotic. The non transformed bacteria will not be able to grow in such a media containing antibiotics.

12) List and explain some advantages and use of PCR technique.

ADVANTAGES –

It’s a simple technique. It’s highly sensitive. It’s a technique that had different applications as mentioned below.

USES -

DNA fingerprinting (forensic and paternity testing) – Regions of DNA can be amplified and compared with DNA of interest.

Genome mapping – Regions of DNA can be amplified and compared.

Disease diagnosis and research – genes of interest can be amplified.

Other uses of PCR are in sequencing, microarray, cloning, mutation studies etc.

16) Three basic steps of conventional PCR

Denaturation – Separate the DNA strands (94°C)

Annealing – Attach primers to the DNA (55°C)

Extension – Starting from primer, DNA polymerase synthesises DNA (72°C)

YAC

BAC