Question

which series lists the correct order of steps of binary fission from first to last?
○ sex pilus connects two cells ® plasmid dna is transferred ® complementary dna strands are created ® cells separate
○ live cells bind to degraded cells ® dna is transported across the membrane ® dna is incorporated into recipient’s dna
○ virus infects bacterial cell, new viruses are made ® dna is assembled in new virus ® new virus infects another bacterial cell and transfers dna
○ dna is copied ® dna molecules attach to cell membrane ® cell membrane elongates and pinches off ® two identical cells are produced

Explanation:

Binary fission is a form of asexual reproduction in prokaryotes (like bacteria). The correct steps are: first, the DNA is copied (replicated) so there are two identical copies. Then, the DNA molecules attach to the cell membrane. Next, the cell membrane elongates, and as it does, it pinches off, separating the two sets of DNA and the cytoplasm. Finally, two identical daughter cells are produced.

Let's analyze the other options:

• The first option describes conjugation (involving sex pilus and plasmid transfer), not binary fission.
• The second option describes transformation (DNA uptake from degraded cells), not binary fission.
• The third option describes transduction (virus - mediated DNA transfer), not binary fission.

Only the last option follows the steps of binary fission: DNA replication, DNA attachment to membrane, membrane elongation and pinching, and cell separation.

Answer:

DNA is copied Ⓡ DNA molecules attach to cell membrane Ⓡ cell membrane elongates and pinches off Ⓡ two identical cells are produced