Cell Division and Mitosis Quiz

Cell Division

• Cell division is a fundamental process for creating life in all organisms.
• It ensures the continuation of their existence, growth, and tissue replacement, and reproduction in multicellular organisms.
• Cell division is also known as cell reproduction.
• During cell division, one cell divides into two daughter cells.
• Three mechanisms of cell reproduction exist: binary fission, meiosis, and mitosis.

Learning Objectives

• Identify the stages of mitosis.
• Understand the role of mitosis in cell growth and repair.
• Apply knowledge of mitosis to real-life examples.
• Identify the stages of meiosis.
• Understand how meiosis contributes to genetic diversity.
• Determine the importance of genetic diversity for ecosystems.
• Define sexual reproduction and its importance in biodiversity.
• Identify and describe the types of sexual reproduction in plants and animals.

Mitosis

• Mitosis is a common form of eukaryotic cell division.
• Somatic cells (cells that do not become sex cells) use mitosis.
• Mitosis produces two genetically identical cells.
• It's crucial for growth and tissue repair.

Stages of Mitosis

• Prophase: The nuclear envelope starts breaking down. Chromatin condenses to form chromosomes. Centrosomes move to opposite cell ends where microtubules begin to form.
• Metaphase: Chromosomes line up in the center of the cell. Microtubules attach to each chromosome's centromere.
• Anaphase: The chromosome pairs separate and move to opposite ends of the cell.
• Telophase: The microtubules disappear. The chromosomes decondense. Two new nuclear envelopes form, each containing the information for a new cell.
• Cytokinesis: The cytoplasm splits, creating two separate daughter cells.

Interphase

• The period between two consecutive mitoses.
• During interphase, the DNA is replicated.
• The cell takes internal and external measures to prepare for reproduction.

Meiosis

• Meiosis is a process of cell division where a single cell divides twice and produces four daughter cells.
• These daughter cells (sex cells) have half the amount of genetic material compared to the original cell.
• Meiosis is crucial for sexual reproduction.

Stages of Meiosis I

• Prophase I: Chromosomes condense, the nuclear envelope breaks down. Crossing over happens - genetic material is exchanged.
• Metaphase I: Chromosomes align in pairs in the center of the cell.
• Anaphase I: Chromosome pairs separate and move to opposite ends of the cell.
• Telophase I: Two new nuclei form around each set of chromosomes. The cytoplasm splits, forming two haploid daughter cells.

Stages of Meiosis II

• Prophase II: Chromosomes condense, the nuclear envelope breaks down in both cells.
• Metaphase II: Chromosomes align single file in the center of each cell.
• Anaphase II: Sister chromatids separate and move to opposite ends of each cell.
• Telophase II: Four new nuclei form around each set of chromosomes. The cytoplasm splits, forming four haploid daughter cells.

Types of Cell Reproduction

• Binary fission: A method where the genetic material of a parent cell is replicated and then divided into two genetically identical daughter cells. This is common among unicellular organisms like bacteria, protozoans, and archaeans.

• Budding: A new organism develops from a small part of the parent's body. A bud forms which detaches to develop into a new organism.

• Fragmentation: Involves the development of new organisms from fragments of a parent organism. The whole body can be involved, or fragments can sprout into new organisms. A term called autotomy is used for self-cutting behavior used as a defense mechanism.

• Regeneration: The ability to replace lost body parts. It happens via mitosis, and certain organisms can regenerate body parts.

Sexual Reproduction

• Sexual reproduction involves the union of male and female sex cells (gametes).

• Fertilization occurs when sperm fertilizes an egg and produces an offspring that is genetically different from both parents.

• Types of fertilization: -External fertilization: Both sperm and eggs are released into the external environment to meet and fuse. -Internal fertilization: Sperm are deposited within the female reproductive tract for fertilization to occur.

Plant Reproduction

• Plant fertilization is the union of the female and male gametes, such as the egg and pollen. Artificial and natural vegetative propagation are two methods that do not involve the union of gametes:

• Artificial Propagation methods: -Cutting: A part of the plant is cut off from the mother plant and placed in a new environment to grow into a whole new plant. -Layering: A shoot or branch from a parent plant is bent and buried in the soil so that roots grow from the shoot. -Grafting: A part of one plant (scion) is joined with a stem of another plant (stock) to produce a new plant that has combined traits.

• Natural Reproduction methods: -Runner/Stolon: A horizontal stem that develops roots and branches called nodes. -Bulb: A short, underground stem with fleshy leaves called scales. -Tuber: A modified root that grows new plants.

  • Rhizome: A horizontal underground stem that has nodes. -Corm: A short, vertical stem with buds where new plants develop.

• Pollenation: The act of transferring pollen grains from the males anther to the female stigma.

Asexual Reproduction

• Does not involve the union of gametes.
• Where an individual reproduces offspring without the involvement of another individual of the same species.
• Types of asexual reproduction include: Binary fission, Budding, Spore Formation, Parthenogenesis, Fragmentation, and Vegetative Propagation.