The Cell Oops, different type of cell

The Cell There that’s better!

I. Discovery of the Cell A. Robert Hooke (1665) used a microscope to look at dead plant cells (“little boxes”) thin slices of cork

B. Anton van Leeuwenhoek (1673) first person to look at living cells.

c. The cell theory 1.Living things are composed of one or more cells. 2.In organisms cells are the basic units of structure and function. 3.New cells can only be made by existing cells.

D. Evidence for the cell theory 1. Matthias Schleiden (1838) concluded plants were made of cells. 2. Theodor Schwann (1839) concluded animals were made of cells. 3. Rudolf Virchow (1855) found that cells only come from other cells.

II. Cell Diversity A. Size 1.Nerve cells can be very large. 2.Most plant and animal cells are micrometers (0.002 inches) 3.Bacterial cells 0.2 micrometers ( inches) 4.Cells are limited in size by the ratio of their outer surface area to their volume

a. Surface area= 2 (L×H + L×W + H×W) b. Volume= L×W×H c. Volume is a measure of space (increases by the cube of the sides) d. Surface area is the amount of exposed surface (increases by the square of the sides) e. Volume increases more rapidly than surface area f. Many materials essential to the cell must enter through the surface

Side Length Surface Area Volume Surface Area to Volume Ratio 1 mm 6 mm 2 1 mm 3 6:1 2 mm 24 mm 2 8 mm 3 3:1 3 mm 54 mm 2 27 mm 3 2:1

B. Shape 1. Variety of shapes a. Nerve cellb. Skin Cell c. White and red blood cells

C. Internal Organization 1. Cells contain internal structures called organelles. 2. Cells are surrounded by a cell membrane called a phospholipid bilayer 3. The Nucleus contains genetic information and controls cell function.

4. Eukaryotes: organisms that contain a membrane bound nucleus and organelles.

5. Prokaryotes: no membrane bound nucleus or membrane bound organelles (bacteria) Although new studies have shown they have “microcompartments” on the molecular level that may act as organelles