Download
1 / 9
90 likes | 224 Vues
Explore the fascinating journey of cell discovery, starting with Robert Hooke's observations in 1665 when he used a microscope to examine cork, coining the term "cellulae" for the tiny structures he saw. We'll also delve into Antonie van Leeuwenhoek's contributions in 1673 as he unveiled bacteria and the differences between plant and animal cells. Learn about the fundamental principles of cell theory, which state that all living organisms are made of cells, that cells are the basic units of life, and how they replicate. Discover the key distinctions between prokaryotic and eukaryotic cells, contributing to the rich diversity of life.
E N D
Unit One Notes Cells – theory
THE FIRST OBSERVED CELLS • Robert Hooke (1665) – a British scientist who used a homemade microscope • Hooke looked at a piece of cork from the bark of an oak tree • It looked like the small rooms monks lived in at that time, so he named them Cellulae, which means “little room” in Latin • He could not see animal cells because they did not have a cell wall • Interesting fact – all known portraits of Hooke were destroyed in part because of an ongoing fued with Isaac Newton
SEEING CELLS IN OTHER LIFE FORMS • LEEUWENHOEK – IN 1673, THIS DUTCH MERCHANT WHO WAS INSPIRED BY HOOKE LOOKED AT POND SCUM UNDER THE MICROSCOPE. HE ALSO LOOKED AT GOOP SCRAPED OFF OF TEETH. • HE WAS THE 1ST PERSON TO SEE BACTERIA (CALLED THEM WEE BEASTIES), AND REALIZE THAT ANIMAL CELLS WERE DIFFERENT FROM PLANT CELLS
Cell Theory A fundamental idea of modern biology: • The three principles of the cell theory state: • All living organisms are composed of one or more cells • Cells are the basic unit of structure and organization of all living organisms (basic unit of life) • Cells arise only from existing cells, with cells passing copies of their genetic material on to their daughter cells. (cells make more cells)
Two Types of Cells • Cells come in different shapes and sizes based on the function they perform. • Cells have been grouped into 2 broad categories based on their internal structures: • Prokaryotic • Eukaryotic (these are generally 1-100x larger)
Two Major Types of Cells Prokaryotic Eukaryotic Cells without a nucleus Example: Bacteria Cells with a nucleus and other membrane bound structures. (Plant and animal cells)
Eukaryotic Cells Plant Cells Animal Cells Have Cell Walls A Large Vacuole Chloroplasts Have a Cell Membrane Small Vacuoles No Chloroplasts
Eukaryotic Cells cont. • Eukaryotic cells are larger and more complex • Have specialized internal structures – called organelles (like a nucleus) • Most multicellular organisms are eukaryotes (although some unicellular organisms like yeast are eukaryotes) • Eukaryotic cells have specialized functions (you have over 200 types of cells) • Believed to have evolved from prokaryotes; has led to cell diversity that helps organisms better adapt to their environments.
