Question

_______ and ______ have the ability to transform normal cells into cancerous cells.

Answer 1

Retroviruses are RNA viruses with RNA as the genetic material. After entering the host cell they reverse transcribe RNA into DNA and inserts their DNA into the host genome. Retroviruses have the ability to transform normal animal cells into cancerous cells. There is a lot of scientific evidence to support the same. Retroviruses have also been disarmed and are now used to deliver desirable genes into animal cells.

Tumour inducing (Ti) plasmid is present in the bacterium, Agrobacterium tumefaciens, which is a pathogen of several dicot plants. This bacteria naturally delivers its “T-DNA” piece of Ti plasmid to the host. This leads to transformation of normal plant cells into tumour cells to produce chemicals required by the bacterial pathogen.

Plasmid is an autonomously replicating circular extra chromosomal DNA found in bacteria. All plasmids do not cause cancer.

YAC (Yeast artificial chromosome) is a molecule that contains DNA obtained from yeast. It is used to clone very large DNA fragments. It has a very high insert capacity. It can carry DNA fragments having a size of 200–2000 kb.

BAC (Bacterial artificial chromosome) which is circular DNA as it is obtained from Bacteria, a prokaryote. It has an insert capacity of up to 350 kb.