Presentation on theme: "Discovery of Cells. First to View Cells In 1665, Robert Hooke used a microscope to examine a thin slice of cork What he saw looked like small boxes so."— Presentation transcript:
Discovery of Cells
First to View Cells In 1665, Robert Hooke used a microscope to examine a thin slice of cork What he saw looked like small boxes so he called them cells
Anton van Leeuwenhoek In 1673, Leeuwenhoek was first to view organisms under a microscope He looked at pond water & plaque he scraped from his teeth
Development of Light Microscope Leeuwenhoek was the first scientist to describe living cells as seen through a simple microscope Simple Light Microscope - One lens and uses natural light Compound Light Microscope - More than one lens to magnify –Magnifies up to 1500 times.
CELL THEORY All living things are made of cells Cells are the basic unit of structure and function in an organism (basic unit of life) Cells come from the reproduction of existing cells (cell division) NEED TO KNOW!!!
Prokaryotes Simplest type of cell Lack a nucleus or membrane bound organelles Single, circular chromosome Bacteria and Archaebacteria
Prokaryotes DNA located in the center Cell membrane AND cell wall Ribosomes to make proteins May have cilia/pilli/flagella to aid in movement
Eukaryotes HAVE a nucleus and membrane bound organelles Protists, fungi, plants, and animals Larger and more complex type of cells
EukaryoticCell Eukaryotic Cell Nucleus that contains DNA Cell membrane Specialized organelles –Where chemical reactions occur
Number of Cells Unicellular Organisms –Organism is only one single cell Multicellular Organisms –Complex organisms with cells organized into tissues, organs, systems
Looking at Cells A cells shape reflects its function –Can be long and flat, branched, round, etc Cell size is limited by the cells surface area to volume ratio –The larger the cell, the more nutrients it needs and waste it produces