Because of the fission process that consumes the fuels, the old fuel rods must be changed periodically to fresh ones (this period is called a cycle). However, only a part of the assemblies (typically one-third) are removed since the fuel depletion is not spatially uniform.
In fertilization, the sperm and egg both contain one set of chromosomes. the father (sperm) and one from the mother (egg). In SCNT, the egg cell's single set of chromosomes is removed. chromosomes. come from the somatic cell.
The most commonly used cloning vectors are E. coli plasmids, small circular DNA molecules that include three functional regions: (1) an origin of replication, (2) a drug-resistance gene, and (3) a region where DNA can be inserted without interfering with plasmid replication or expression of the drug-resistance gene.