Cell Structure and Function Chapter 7 Cell Structure and Function

7 -1 Life Is Cellular: The History of the Cell Theory Anton van Leeuwenhoek: Microscope inventor In the early 1600s the microscope was invented. Anton van Leeuwenhoek was the first to use a microscope to study nature. van Leeuwenhoek observed tiny living organisms in pond water. He called them “animalcules.”

Antony van Leeuwenhoek. Letter of June 12, 1716 . . . my work, which I've done for a long time, was not pursued in order to gain the praise I now enjoy, but chiefly from a craving after knowledge, which I notice resides in me more than in most other men. And therewithal, whenever I found out anything remarkable, I have thought it my duty to put down my discovery on paper, so that all ingenious people might be informed thereof. Antony van Leeuwenhoek. Letter of June 12, 1716

An example of the early type of microscope Leeuwenhoek used

The Discovery of Cells: Robert Hooke 1665: Robert Hooke looked at plant tissue (cork) under a microscope. Hooke noticed tiny chambers which he named cells. (after the rooms in ancient monasteries.) Hooke’s discovery led to other work that concluded that cells are the basic unit of all forms of life.

Schleiden, Schwann and Virchow : “All living things are made of cells 1838: Matthias Schleiden, a German botanist, concluded that all plant are made of cells.

1839: Theodor Schwann, German scientist, concluded that all animals are also made of cells.

1855: Rudolf Virchow, a German physician concluded that “where cells exist, there must have been a preexisting cell.”

The Cell Theory (Learn this NOW!) All living things are composed of cells. Cells are the basic units of structure and function in living things. New cells are produce from existing cells.

Basic Cell Structures Cells come in many shapes and sizes. “normal” cells are from 5 to 50 microns in diameter. Some cells are huge! (Egg Cells, Nerve cells.) Many one-celled animals can be seen without a microscope.

Basic Cell Structures (Cont.) Structures common to most cells Cell membrane – A flexible membrane that is “selectively permeable.” Cell wall – Provides protection and support. Not found in all cells. Nucleus – Contains genetic material and controls cell’s activities. Cytoplasm – Material inside the cell excluding organelles.

Prokaryotes and Eukaryotes Prokaryotes – (bacteria) smaller and simpler than other cells. Lack a membrane bound nucleus and other organelles. Eukaryotes – (all plants, animals, fungi, protists) Cells that do contain a nucleus and other membrane bound organelles