A nuclease (also archaically known as nucleodepolymerase or polynucleotidase) is an enzyme capable of cleaving the phosphodiester bonds between nucleotides of nucleic acids. Nucleases variously effect single and double stranded breaks in their target molecules. In living organisms, they are essential machinery for many aspects of DNA repair. Defects in certain nucleases can cause genetic instability or immunodeficiency.[1] Nucleases are also extensively used in molecular cloning.[2]
Depiction of the restriction enzyme (endonuclease) HindIII cleaving a double-stranded DNA molecule at a valid restriction site (5'–A|AGCTT–3').
There are two primary classifications based on the locus of activity. Exonucleases digest nucleic acids from the ends. Endonucleases act on regions in the middle of target molecules. They are further subcategorized as deoxyribonucleases and ribonucleases. The former acts on DNA, the latter on RNA.[2]
Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment.
Answer:
Suppose you have a parent plant with purple flowers and a parent plant with white flowers. Because the b allele is recessive, you know that the white-flowered parent must have the genotype bb. The purple-flowered parent, on the other hand, could have either the BB or the Bb genotype. The Punnett square in Figure below shows this cross.
Explanation:
Because the exact copy of the parent cell is produced, only one organism is needed for it to occur.
