Plate 15 - Bacterial Reproduction

Sexual vs. Asexual Reproduction Asexual – no change in genetic makeup of daughter cells, all are identical Sexual – daughter cells are genetically different than parents

Gametes Gametes – sex cells (sperm & egg), the result of meiosis

Binary Fission Binary = 2 Fission = split apart Asexual reproduction Occurs after a period of growth

Binary Fission Steps 1.DNA replication (time frame is minutes or hours) 2.Protein synthesis (~ 40 minutes) 3.Replication of structures (7 minutes) 4.Cytoplamic separation & pinching (7 minutes) 5.New cell walls form (7 minutes)

DNA DNA is copied by cell enzymes (transcription) Makes 2 copies (looped DNA)

Cytoplasm Increase in metabolism causes rapid manufacture of cytoplasm & structures Causes increase in mass of cell & length

Effects of Antibiotics Penicillin acts to weaken cell wall Cell wall is so weak that cell bursts and dies (like using paper instead of concrete blocks for walls) Only works on growing cells Mature cells are NOT affected

Daughter Cells “Daughter” is a misnomer, but still used (not female)

Generation Time Genetically determined, different species different times to undergo binary fission Ex: E. coli = 20 minutes Environment also determines the generation time (cold temperatures slow it down) Measured from the start of one binary fission event to the start of the next