Chapter 3, Section 1 The Diversity of Cells

Different populations BIOME/ ECOSYSTEM COMMUNITY POPULATION ___________  __________ ___________ All the organisms of one species in an area Different populations interconnected IMAGE SOURCES: see last slide

___________  __________ ___________ ORGAN SYSTEMS ORGANISM ORGANS ___________  __________ ___________ Different tissues working together Different organs working together IMAGE SOURCES: see last slide

____________  ____________ TISSUES CELLS ____________  ____________ Similar cells working together IMAGE SOURCES: see last slide

What is a Cell???? A cell is the smallest unit in a living thing that can perform all of the functions necessary for life

Robert Hooke 1665- ______________________ used a microscope to examine a thin slice of cork and saw “little boxes” Robert Hooke He called them “CELLS” because they looked like the small rooms that monks lived in called Cells Microscope image: http://www.answers.com/topic/microscope Cork image: http://www.cortex.de/img_kork/cork_cells_big.jpg Hooke image: http://www.metaweb.com/wiki/upload/5/5c/Hookeyoungmtwb.jpg

Anton van Leeuwenhoek 1673- ___________________________________ a Dutch microscope maker was the first to see LIVING ORGANISMS. Anton van Leeuwenhoek Microscope/Leeuwenhoek image: http://www.answers.com/topic/microscope Animation from: http://web.jjay.cuny.edu/~acarpi/NSC/13-cells.htm

Overview of Cell Theory History Lets Read an Article!

1838- German botanist __________________________concluded that ALL PLANTS are made of cells Matthias Schleiden Plant image: http://www.epa.gov/maia/images/classification.gif Schleiden image: http://web.visionlearning.com/events/Schleiden_Apr5_2005.htm

Theodor Schwann 1839- German zoologist _________________________concluded that Theodor Schwann ALL ANIMALS ARE MADE OF CELLS Schwann image: http://home.tiscalinet.ch/biografien/biografien/schwann.htm Animals image: http://animaldiversity.ummz.umich.edu/index.htm

The Cell Theory Schwann wrote the first two parts of the cell theory All organisms are made of one or more cells The cell is the basic unit of all living things

Rudolph Virchow 1855- German medical doctor _____________________ saw dividing cells in the microscope and reasoned that cells come from other cells Rudolph Virchow Virchow: http://www.parlament-berlin.de/Galeriecopy.nsf/0/8ABC720262898739C1256A480037F869?OpenDocument Mitosis: http://biology.dbs.umt.edu/biol101/labs/lab_6_images/sect01and06/Rebecca,%20tanner,%20and%20liam%20mitosis%20root%20tip.jpg

CELL SIZE http://facstaff.bloomu.edu/gdavis/links%20100.htm The yolk of an egg is a single cell! 50 human cells could fit on the dot of the “i” in your textbook! Typical cells range from: 5 – 50 micrometers (microns) in diameter

The answer has to do with the cell membrane. Balloon Demo Why Are Cells So Small? One characteristic of cells is that they are very small. Why are cells so small? The answer has to do with the cell membrane. Balloon Demo

Cells Need a Large Surface Area Everything the cell needs to take in or has to get rid of has to go through the cell membrane. Therefore the cell membrane needs to have a large surface area in relation to the volume of the cell. As a cell gets bigger, so does its surface area.

However, the volume of a cell increases at a faster rate than the surface area of its cell membrane. If a cell gets too large, its cell membrane will not have enough openings to meet the demands of its volume. This limits the size of cells.

Parts of a Cell All cells, no matter what size or shape have the following: Cell membrane and cytoplasm Organelles Genetic material

Two Kinds of Cells There are two basic types of cells: Prokaryotes (which include bacteria and archaebacteria) Eukaryotes

Prokaryotes Even though these organisms have DNA, they do not have a nucleus (we’ll study this soon!!!!) Bacteria Bacteria are everywhere Bacteria are unicellular Have ribosomes (we’ll study these later!!!)

Archaebacteria - are similar to bacteria, but their ribosomes are different and they live in some pretty extreme places, like near volcanic vents or even in sewage!

Prokaryotic Cell

Eukaryotes Eukaryotic cells are the largest cells Eukaryotes have a nucleus Most are multicellular