Chapter 7: The Microscope and Cell Theory
Chapter 7:
The Microscope and Cell Theory
Try these websites for fun!
• http://learn.genetics.utah.edu/content/begin/cells/insideacell/
• http://www.sheppardsoftware.com/health/anatomy/cell/cell_game.htm
Cell Theory
• Term “cell” was coined in 1665 by Robert Hooke when he looked at a slice of dried cork.
• Cell Theory1. All living things are made
of cells.
2. Cells are the smallest “living” unit
3. All cells came from previously existing cells.
Then
Now
2 main types of cells
• Prokaryotic– Lack membrane
enclosed organelles
– Lack a nucleus– Only Unicellular– Bacteria
• Eukaryotic – Have membrane
bound organelles– Have a nucleus– Can be unicellular or
multicellular– Plant and Animal Cells– 10 Times Larger than
Prokaryote Cells.
What each cell has:• Prokaryote
– DNA– Plasma Membrane– Ribosomes– Cell Wall– Cytoplasm– Cilia/flagella
• Eukaryote– Nucleus w/ DNA– Plasma membrane– Ribosomes– Cell wall (plant)– Cytoplasm– Endoplasmic Reticulum– Mitochondria– Golgi apparatus– Large vacuole (plant)– Chloroplast (plant)– Lysosome (animal)– Cilia/flagella (animal)
Microscopes
• In the 1600’s the first microscope was invented.
• Microscopes magnify objects
• Two main types of microscopes– Compound light microscope
• Multiply lenses to find out magnification
• Magnifies about 1500 times
– Electron microscope• Uses a beam of electrons to magnify
structures• Up to 500,000 times magnified!!!!
Anton van Leeuwenhoek
Microscope parts
tube
stage clips
Light/mirror
base
diaphragm
eye piece
10x objective
40x objective
100x objective
fine adjustment
rough adjustment
stage
armnosepiece
Plasma (cell) Membrane
• Physical & chemical boundary of all cells
• A double layer called the phospholipid bilayer. – It is selectively permeable (semipermeable)
meaning only certain things are let in and out• Gate-keeper of cell
Function of Proteins in Membrane
1. Transport Proteins- move large things in and out of cell
Ribosomes • Sites of protein synthesis
– Proteins are the main product produced by the cell
• Not considered a membrane-bound organelle so they are found in prokaryotes and eukaryotes
• Control center of cell (controls all cellular activites)– Contains DNA – Contains nucleolus where
ribosomes are made
Nucleus
Nucleolus
• Located inside of the nucleus
• Contains RNA and proteins
• Makes ribosomes
Nuclear membrane/ Nuclear envelope
• The double-layered membrane enclosing the nucleus of a cell.
Endoplasmic reticulum• Transport system of cell (transports materials)
– Rough Endoplasmic reticulum (RER) has ribosomes
– Smooth Endoplasmic reticulum (SER) for lipid synthesis and storage
Golgi Apparatus• Involved in packaging and secretion of proteins
– The cellular post office– Also called golgi body
Mitochondria
• Where energy for the cell is made (ATP)
• Site of cellular respiration
Adenosine Tri Phosphate (ATP)
Lysosomes• Found in animal cells
– Digest and recycle worn out cell parts– Destroy foreign invaders
Plant cell only• Large vacuoles for storage of
water and sugars
• Cell wall made of cellulose for support and protection
• Chloroplasts– Where photosynthesis happens
(glucose is made from water, CO2, & sunlight)
– Give green color
Two organelles have their own DNA
• Mitochondria and Chloroplasts have their own DNA because they were probably once free-living bacteria that were “eaten” by a larger cell and instead of being digested, they became part of that cell as an organelle