Microscopes Cells Microscopes and Cells History Hooke In
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Microscopes & Cells
Microscopes and Cells: History Hooke • In 1663, Robert _____ coined the term “cells” • 10 years later, Anton van Leeuwenhoek _________ observed bacteria and protozoa Browne • In 1833, Robert _____ observed and coined the term “nucleus”
Guten Tag, Dr. Shwann Cell Theory: History Guten Tag, Dr. Schleiden • In 1838 (and 1839) German scientists, Matthias Schleiden ________ & Theodore Schwann ________ independently came up with the “Cell Theory” It appears we have come up with a very similar theory… What shall we call this theory?
Cell Theory 1. All living things are composed of one or more cells. 2. Cells are organisms' basic units of structure and function. 3. Cells form by free-cell formation, similar to the formation of crystals (spontaneous generation).
• In 1855, German physician Rudolph Virchow discovered that… all cells must come from pre -existing cells. Please add the above as point #4 to the cell theory
How big are cells? • Eukaryotic cells include plant animal cells. _______ & _______ • Most eukaryotic cells are 100 m. between 10 __ and ___ • What is the limit of the light microscope? 0. 2 m • Why? It is limited to the visible light spectrum • What is used to see smaller objects? Electron Microscopes _________
Electron Microscopy • ______ Transmission Electron Microscopes (TEM) emit light through a thin piece of heavy metal ion stained tissue Scanning Electron • ____ Microscopes (SEM) reflect light off of a piece of heavy metal ion stained tissue
Prokaryotic Cells (cells without a nucleus) for ex. bacteria Label this diagram in your handout DNA (Nucleoid) Ribosomes Plasma Membrane Cytoplasm Cilia Cilium Flagella Flagellum TEM of a bacterium
Eukaryotic Cells (cells with a nucleus) Plant cell Animal cell Eukaryotic cells include both plants and animal cells
Differences and similarities between Prokaryotes and Eukaryotes Differences Prokaryotes lack: 1. True nucleus 2. Membrane bound organelles Prokaryotes are much smaller than eukaryotes (prokaryotes are ~1 – 10 m and eukaryotes are 10 – 100 m ) Similarities Both have: 1. DNA 2. Cytoplasm 3. Ribosomes 4. Plasma Membrane