Cell Theory

  1. What is a cell? Give 3 examples of a cell

A cell is the basic unit of life that can perform all necessary functions for an organism.

Examples of cells include:

  • Red blood cells: responsible for transporting oxygen throughout the body.

  • Neurons: specialized cells that transmit nerve impulses.

  • Epithelial cells: form protective layers on surfaces of organs and structures.

  1. State the cell theory.

  • All living things are made up of one or more cells

  • Cells are the basic unit of life

  • Cells come from pre-existing cells

  1. Define eukaryotic cells. Give 3 examples

  • Eukaryotic cells are cells with a true nucleus

  • Organelles surrounded by membrane

Examples of eukaryotic cells include:

  • Animals

  • Plant

  • Fungi

  1. What are the features of all eukaryotic cells?

  • Membrane-bound organelles, including a nucleus that contains genetic material

  • Complex cellular structures that allow for specialized functions

  • Larger size compared to prokaryotic cells

  • Cytoskeleton that provides structural support and shape

  1. Define prokaryotic cells. Give 3 examples.

  • Prokaryotic cells are cells with no true nucleus

  • They don’t have membrane-bound organelles such as : Mitochondria, chloroplasts

Examples of prokaryotic cells include:

  • Bacteria

  • Archea

  • Blue-green algae (Cyanobacteria)

  1. What are the features of all prokaryotic cells?

  • Lack of a true nucleus: Prokaryotic cells have their genetic material located in a nucleoid region instead of a membrane-bound nucleus.

  • Cell wall: Most prokaryotes possess a rigid cell wall that provides structural support and protection.

  • Smaller size: Prokaryotic cells are generally smaller than eukaryotic cells, typically ranging from 0.1 to 5.0 micrometers in diameter.

  • Simple structure: They lack membrane-bound organelles, which are present in eukaryotic cells.

  • Reproduction: Prokaryotic cells reproduce asexually through binary fission, a simpler process than mitosis.

  1. Describe the following organelles and state their function. Where in the cell are they

    found?

    • Nucleus: The nucleus is the membrane-bound organelle that contains the cell's genetic material (DNA) and is typically located in the center of eukaryotic cells. It regulates gene expression and mediates the replication of DNA during the cell cycle.

    • Nucleolus: The nucleolus is a dense structure found within the nucleus, primarily responsible for the synthesis of ribosomal RNA (rRNA) and the assembly of ribosome subunits, which are essential for protein synthesis.

    • Vesicles: Vesicles are small membrane-bound sacs that transport materials within the cell, playing a crucial role in processes such as secretion, endocytosis, and intracellular transport.