Cell Unit Chapter 6

Definition of Cell? Basic Unit of Life. The smallest part of an organism that is alive because it can carry out all of the characteristics of life. Understanding is relatively recent

Cells Background What developed first telescope or microscope? Why? Development of cell is tied to the development of?

History of Cell Biology Robert Hooke (English)

Robert Hooke (cont’d) Bark of Oak Trees (cork) Bark of Oak Trees (cork) Magnified 30 X First to use term “cell”- reminded him of monastery

History of Cell Biology (Anton Van Leewenhoek) Involved with textiles Involved with textiles Produced high quality hand lenses to count the threads in cloth Produced high quality hand lenses to count the threads in cloth 300X 300X First to observe “living” organisms in pond water First to observe “living” organisms in pond water Protists called “animacules” Protists called “animacules”

Leewenhoek’s Microscope

Schleiden 1838 (German) 1. Botanist 2. “All plants are made of cells”

Schwann 1839 (German) Zoologist “All animals are made of cells.”

Virchow 1858 “Cells only come from pre-existing living cells.”

Cell Theory All life is composed of cell(s) where all the processes of metabolism and heredity occur Smallest living organism is a cell Cells can only come from other living cells Biogenesis

Timeline

Description of cells Size- many different sizes, most are microscopic Smallest-bacteria

Cell Size Largest- yolk cells in egg, nerve cells

Other examples: Red Blood Cells, Skin Cells, Amoeba Red Blood Cells, Skin Cells, Amoeba

Cell Shape No Specific shape, but… No Specific shape, but… 1. Plant cells- usually rectangular in shape due to the cell wall. 2. Animal cells- usually rounded due to lack of a cell wall.

Plant vs. Animal Cells

Cell Types All Cells are divided into one of two categories: All Cells are divided into one of two categories: Prokaryotes Prokaryotes Eukaryotes Eukaryotes

Prokaryotes (before nucleus) No true nucleus, have a nucleoid No true nucleus, have a nucleoid Primitive, tiny Primitive, tiny Bacteria, cyanobacteria Bacteria, cyanobacteria No complex internal structures (organelles) No complex internal structures (organelles) Kingdom Monera Kingdom Monera No separation of genetic material from rest of cell No separation of genetic material from rest of cell Ribosomes and DNA Ribosomes and DNA

Prokaryotes

Eukaryotes (true nucleus, encloses DNA) Algae, fungi, protozoan, plants, animals Algae, fungi, protozoan, plants, animals Nuclear bound genetic information Nuclear bound genetic information Extensive compartmentalization in cytoplasm Extensive compartmentalization in cytoplasm Complex membrane bound organelles Complex membrane bound organelles

Eukaryotes