Answer:
Option 3, Chromatids remain attached to one another until anaphase
Explanation:
Centromere lies at the center, end or other points of the chromosome and joins the two sister chromatids. During cell division, the spindle fibers attaches at the centromere and detaches the chromosomes during the anaphase of the cell division to ensure that each daughter cell gets equal number of chromosomes at the end of mitosis. Centromere plays an essential role in the separation of chromosomes.
Hence, option 3 is correct
Supercoiling is an important property of DNA tertiary structure that affects essential processes such as replication and transcription. Negative supercoiling is very important. Negative supercoiling causes unwinding of DNA and it makes the DNA strand ready for biological processes such as replication and transcription. Negative supercoiling is introduced in a DNA with the help of enzyme topoisomerase enzymes I and II. In bacteria topoisomerase enzyme II is called gyrase.
Coltan is short for columbite-tantalite, a dull metallic ore. When refined, coltan becomes a heat resistant powder.
Answer:
Option B, can be used to either sterilize or pasteurize, depending on the dose of radiation
Explanation:
Sterilization by radiation has started since 1895. However, commercial food irradiation plant was installed at Stuttgart, Germany in 1958. In general gamma radiation is used for sterilization purposes which disrupts the sub-atomic particles involved in the formation of the microorganism at an early stage by damaging their genetic material such as DNA or RNA with in their cells. Once the genetic material i.e DNA or RNA is damaged, the cell dies automatically.
Hence, option B is correct
