The Discovery of Cells Later, the observations of Matthias Schleiden and Theodore Schwann (1830’s) lead to the cell theory: All organisms are made of one or more cells The cell is the basic unit of structure and organization of living things. All cells come from pre-existing cells.

Cell Parts There are 4 common parts of cells: Cell Membrane Outer protective layer of the cell. Cytoplasm Fluid inside the cell that helps keep everything inside safe and supported. Organelles Small structures with very specific functions found inside the cell. Like mini-organs for the cell Genetic Material DNA The instructions for the cell Either floating in the cell (prokaryotes) or found in the nucleus (eukaryotes) All cells have these structures in common, no matter what kind of cell it is

Types of cells There are 2 categories of cells – Eukaryotic- “True Core” These contain membrane bound organelles like a nucleus Includes Plant and Animal cells – Prokaryotic- “Before Core” These are primitive cells that lack membrane bound organelles like a nucleus. Includes Bacteria cells

5.2 How plant cells are different 3. Plant cells have a cell wall, but animal cells do not. Cell walls provide structure and support for the plant.

5.2 The cell membrane and nucleus The cell membrane is a thin layer that separates the inside of the cell from its outside environment. It keeps the cytoplasm inside while letting waste products out.

5.2 The cell membrane and nucleus The nucleus is covered with a membrane that allows materials to pass in and out. It’s often called the “control center” of the cell because it contains DNA. The nucleolus acts as a storage area for materials.

5.2 Organelles and their functions Mitochondria are called the “powerhouses” of cells. They produce much of the energy a cell needs to carry out its functions. Creating this energy is called cellular respiration.

5.2 How plant cells are different 1. Plant cells have chloroplasts, but animal cells do not. A chloroplast is an organelle that contains a green pigment called chlorophyll.

5.2 Organelles and their functions Ribosomes are the protein factories of the cell. When ribosomes make proteins, they release them into the ER.

5.2 How plant cells are different 2. Plant cells have a large central vacuole that stores cell sap.

5.2 Organelles and their functions Golgi bodies receive proteins and other compounds from the ER. They package these materials and distribute them to other parts of the cell.

5.2 Organelles and their functions The endoplasmic reticulum (ER) is a series of tunnels throughout the cytoplasm. They transport proteins from one part of the cell to another.

5.2 Organelles and their functions Lysosomes contain enzymes that can break things down. Lysosomes pick up bacteria, food, and old organelles and break them into small pieces that can be reused.