Asexual Reproduction and Cell Division

ASEXUAL REPRODUCTION

  • Defined as the process through which new identical cells or single-celled organisms are created.

Types of Cells Involved in Asexual Reproduction

Eukaryotic Cells

  • Characteristics:

    • Have a nucleus.

    • Contain many chromosomes.

    • Examples: plants, animals, protists, fungi.

Prokaryotic Cells

  • Characteristics:

    • Lack a nucleus.

    • Typically possess 1 chromosome.

    • Examples: bacteria, archaea.

Bacteriophage Viruses

  • Not cellular and considered non-living.

  • Structure:

    • Composed of a protein coat and DNA or RNA.

    • Example: T4 phage that infects bacteria.

Genetic Material in Cells

  • Eukaryotic cells can have:

    • Nuclei (designated as n, 2n, 2nR).

    • Plasmids (extra DNA).

Reasons for Cell Division

  • Growth and maintenance of organisms.

  • Use in genetic engineering.

Cell Cycle Overview

Interphase

  • Divided into the following phases:

    • G1 Phase: Growth phase where cell increases in size.

    • G0 Phase: A resting state where cells are not actively preparing to divide and not looking to reproduce.

    • S Phase: DNA synthesis occurs, resulting in the duplication of chromosomes.

    • G2 Phase: Cell prepares to enter mitosis, ensuring all DNA has been replicated and is undamaged.

M Phase

  • Also known as the Mitotic phase, which includes:

    • Mitosis: Division of the nucleus—subdivided into prophase, metaphase, anaphase, and telophase.

    • Cytokinesis: Division of the cytoplasm, resulting in two identical daughter cells.

Asexual Reproduction Mechanisms

Binary Fission

  • A method used by prokaryotic cells where the cell divides into two equal halves.

Viral Reproduction Cycles

Lytic Cycle

  • A cycle where the bacteriophage takes over a host cell's machinery to reproduce, eventually leading to cell lysis.

Lysogenic Cycle

  • A cycle where the viral DNA is integrated into the host's genome and replicated along with the host's DNA without killing the host initially.

Cancer and Cell Cycle

  • Cancer is associated with malfunctions of cell cycle checkpoints - they govern cell division and growth.

  • Improperly functioning checkpoints can lead to uncontrolled cell growth and tumor development.

Conditions Needed for Growth

  • Ensure the presence of necessary nutrients and environment for cellular growth and division.

  • Discusses methods for microbial control such as prevention, killing methods, and the use of zone of inhibition in antibiotic testing.

  • Positive uses of asexual reproduction for humans and the environment include methods in biotechnology, agriculture, and microbiology.