Cell Reproduction Chapter 10

Cell Reproduction Overview

• Binary fission is an asexual reproductive process in prokaryotes involving DNA replication and cell elongation before membrane closure.
• A septum is a dividing wall that separates daughter organisms in binary fission.
• Karyokinesis, the division of a cell nucleus during mitosis, is absent in binary fission, as prokaryotes lack a nucleus.

Eukaryotic Cell Division Components

• Common components shared between eukaryotic cell division and binary fission: DNA duplication, chromosome segregation, cytoplasmic division.
• Duplicated bacterial chromosomes attach to the cell membrane for distribution into new daughter cells.
• Chromosomes form through tightly packed DNA, often wrapped around histones, which are proteins that help condense DNA into chromatin.

Chromosomes and Genes

• Homologous chromosomes consist of matched pairs that carry genetic information.
• Genes are hereditary units determining specific traits passed from parents to offspring.
• A karyotype is a visual representation of chromosomes arranged by length.

Phases of the Cell Cycle

• G1 phase involves accumulation of DNA, energy, and proteins, preparing the cell for division.
• S phase is dedicated to DNA replication.
• G2 phase focuses on energy replenishment, protein synthesis, organelle duplication, and cytoskeleton dismantling.
• M phase is when actual cell division occurs, encompassing mitosis.

Mitosis Stages

• Interphase serves as a preparatory phase for mitosis, where cells grow and replicate DNA.
• Prophase is the first and longest phase where chromosomes become visible and centrioles migrate to poles.
• Metaphase sees chromosomes align at the cell's equator, connecting to spindle fibers.
• Anaphase involves sister chromatids separating into individual chromosomes and moving apart.
• Telophase marks the end of mitosis with chromosomes gathering at opposite poles, forming two nuclear membranes.

Differences in Plant and Animal Cell Mitosis

• In plant cells, a cell plate forms during division.
• Animal cells utilize centrosomes during mitosis.

Cell Cycle Regulation

• G0 phase is for cells that do not frequently divide.
• Checkpoints in the cell cycle monitor:
  • G1 for cell size and nutrient availability.
  • G2 for DNA replication and cell size.
  • Spindle Assembly for chromosome-fibre attachment.
• Cyclins regulate the timing of transitions between cell cycle phases.
• Proto-oncogenes code for proteins that promote cell growth, while oncogenes can cause cancer.
• Tumor suppressor genes prevent uncontrolled cell division by counteracting oncogene effects.

Test your knowledge on key terms and concepts related to cell reproduction, particularly focusing on binary fission and its processes. This quiz covers definitions and important distinctions in prokaryotic reproduction and the eukaryotic cell cycle. Ready to challenge yourself?