The Diversity of Cells HO#__3__C Bellringer: Cells remain small because their surface area:_________ ratio must stay balanced.

Cells and the Cell Theory Robert Hooke 1665 Cork Saw “little boxes” AKA cells Plants and fungi Cell walls Living cells “juicy”

Finding Cells in Other Organisms Anton van Leeuwenhoek 1673 Pond scum Animalcules “little animals” Animal blood Difference in cell make-up Bacteria Yeast Discovered it makes bread rise…Yummo!

The Cell Theory Schwann- 1839 Virchow- 1858 All organisms are made of one or more cells The cell is the basic unit of all living things Virchow- 1858 All cells come from existing cells. hl503_01_v01fs

Cell Size Supersize Please Value size Egg yolk is one large cell Most cells are microscopic Why??? Must have surface area to volume ratio Bigger cell = more food/wastes Surface area grows slower than volume Not enough nutrients in and not enough wastes out!! We get a big useless blob!!! http://www.cellsalive.com/howbig.htm

Parts of a Cell Cell Membrane (AKA: North Pole Walls and Guard Elves) Protective layer that covers the cell’s surface and acts as a barrier Cytoplasm (AKA: A bowl full of jelly) Fluid inside the cell Organelles (AKA: the elves) Perform functions inside the cell Genetic Material (AKA: Santa) All cells have DNA at some point Controls activities of a cell Kept in a nucleus (AKA: Santa’s Office) only in Eukaryotes Humans- nucleus Bacteria- no nucleus

Two Kinds of Cells Prokaryotes- single celled organisms that do not have a nucleus or membrane bound organelles Two Types Bacteria Archae

Bacteria Single celled Smallest cells known Live anywhere Flagella DNA Capsule Ribosomes Pilus Cell Membrane Cell Wall

Archae Single Celled No Nucleus Has: Three types Ribosomes DNA Cell membrane Three types Heat loving extremophile Salt loving Methane-making

Endoplasmic Reticulum Eukaryotic Cells Lysosome Mitochondria Largest cells 10 times larger than bacteria Still microscopic Have a nucleus Membrane bound organelles Many are multi-cellular Examples Animals Plants Some protists Amoeba Green algae Fungi Yeast Ribosomes Nucleus Nucleolus Ribosomes Endoplasmic Reticulum Golgi Body Cell membrane

What do you know?? What are two differences between a Eukaryotic cell and a Prokaryotic cell?