During which phase of the cell cycle does DNA replication occur? MCQ with Answer and Explanation

Explanation:
Transduction is the transfer of bacterial DNA by a bacteriophage (virus). Transformation is uptake of free DNA, conjugation is direct transfer via pilus, binary fission is reproduction.

Explanation:
Plasmids are small, circular, extrachromosomal DNA molecules in bacteria widely used as cloning vectors in genetic engineering. Restriction enzymes are part of the bacterial immune system, found in bacteria and archaea, not viruses, protecting them against bacteriophages. Polymerase Chain Reaction (PCR) requires a thermostable DNA polymerase (like Taq) to synthesize new DNA strands. Thus, statements 1 and 3 are correct.

Explanation:
Senescence in plants is the biological process of aging, culminating in the structured, programmed death of plant organs (like leaves, flowers, or fruits) or the entire plant. It involves the coordinated breakdown of macromolecules (proteins, nucleic acids, chlorophyll) and the mobilization of nutrients (like nitrogen and phosphorus) from the senescing organ to other growing parts of the plant (like developing seeds). It is a highly regulated process influenced by hormones like ethylene and abscisic acid, and delayed by cytokinins.