1. Cells – the smallest structure that carries out life activities

2. What are cells? Basic unit of structure and function in living things Cells are the smallest living thing that carry out all the functions of living things. Cells breakdown simple sugar to produce energy in a process called cellular respiration

3. Discovery of Cells Robert Hooke was the first to observe and describe cells (1600’s) Hooke observed the cells of cork Antoine van Leeuwenhoek was the first to observe and describe living cells in a drop of pond water (1600’s)

4. Cell theory develops Matthias Schleiden stated that all plants are made up of cells (1838) Theodore Schwann said the cell is the basic unit of structure in animals (1839) Rudolph Virchow said new cells come from cells that already exist, cells divide to make new cells. (1855)

5. The cell theory All living things are made up of one or more cells Cells are the basic units of structure in living things and cells carry on all life processes. Cells come only from other living cells.

6. The main parts of a cell Cell Membrane – structure that surrounds, protects, and controls what enters and leaves the cell Cytoplasm – gel like substance inside the cell where most of the cells activities occur Nucleus – control center of the cell, contains DNA Nuclear Membrane – thin structure that surrounds and protects the nucleus

7. Other Cell Parts or Organelles small structures in the cytoplasm that do a special job for the cell. Mitochondrion Mitochondria(pl) – structure that releases energy, place for cellular respiration Endoplasmic Reticulum – small network of tubes inside a cell that substances move along Ribosomes – small round structures that make proteins Golgi body – packages and sends materials to other places in the cell Vacuole – space in the cytoplasm that stores the different substances a cell needs to survive Lysosome – small round structure that breaks down nutrient molecules and old cell parts