Robert Hooke • English physicist • 1665 - used one of the first light microscopes to look at thin slices of plant tissuesa slice of CORK • Called thousands of tiny chambers “cells,” because they reminded him of a monastery’s tiny rooms. • this discovery motivated scientists to search for cells in other living things.
Anton van Leeuwenhoek • Dutch businessman • One of the first people to use a simple microscope to study nature. • 1674 - observed living things in pond water and made detailed drawings of each kind of organism. • He called these organisms animalcules.
The Final Three • 1838 – Mathias Schlieden found that all Plants are made of cells. • 1839 – Theodore Schwann found that Animals are also made up of cells • 1855 – Rudolf Virchow found that “Where a cell exists, there must have been a preexisting cell.…” or cells come from cells
The Cell Theory • In 1855, a number of scientists put together a theory about cells… • All living things are composed of Cells. • Cells are the basic unit of structure and function in living things. • New cells are produced from existing cells. Who were these scientists?
Prokaryote vs. Eukaryote • Prokaryote - have cell membranes and cytoplasm but do not contain nuclei. • Simple Cells • All bacteria are prokaryotes. • Eukaryote- Contain nuclei. Also have a cell membrane, cytoplasm, and specialized organelles. • Complex Cells • All plants, animals, fungi, and many microorganisms, are eukaryotes. • Eukaryote cells are much larger than prokaryote cells
So Where did these Eukaryotes come from? • Mitochondria and Chloroplasts contain their own DNA genetic information separate from the cells DNA. • So, Scientists have done research and come up with a Theory… • The ENDOSYMBIOTIC THEORY Let’s take a look at this evolution…
The Endosymbiotic Theory • The first eukaryotes may have formed from one bacteria engulfing another without killing it. • Later a symbiotic relationship was formed
Stop and Think… • Are plant and animal cells prokaryotic or eukaryotic? • How does the meaning of prokaryotic or eukaryotic help you answer this question? • Give one or two examples that help you answer this question.
Plant Cells • Cell wall located outside the cell membrane. Cell wall is made from cellulose fibers, and it is used for support & protection • Contains one large vacuole that contains water. Vacuole full = plant is rigid. Vacuole loses water = plant wilts • Chloroplasts = contain chlorophyll, which captures sunlight & converts it into energy
Plant Cell Build a plant cell
Animal Cells • Have no cell wall • NO chlorophyll • CANNOT make their own food
So Plant and Animal Cells are… • Both eukaryotic cells- Both have nucleuses, organelles, cell membranes, cytoplasm
Plant and animal cell differences Plant Cells Cell wall Chloroplasts Large central vacuole No centrioles Animal Cells • Have centrioles • No cell wall • No chloroplasts • No large central vacuole Construct a cell
Levels of Organization • Cells- the basic unit of life • Tissues- a group of similar cells that perform a particular function • Organs- many groups of tissues work together • Organ Systems- A group of organs that work together to perform a specific function • Organism- An entire living being made up of organ systems
Using the following terms, place the levels of organization in the correct order of the chart. -Stomach - Digestive System -Smooth muscle tissue -Muscle Cell Test your Knowledge… ? ? ? ?