It all started with an invention…. The first microscope –Sacharias Jansen, 1595, Middleburg, Holland –It launched great leaps in Astronomy and Biology. –Some of the first great observations with it were made by…

Robert Hooke ( ) –Designed microscopes –Discovered and documented the first “cells” in 1665 Named them after the cells in which a monk sleeps. From:

Antony van Leeuwenhoek ( ) A tradesman from Holland who became fascinated with Hooke’s book Discovered bacteria, protists, sperm cells, blood cells, nematodes, etc. Became an expert lens grinder and made over 500 simple microscopes Acute eyesight and lens grinding skill let him build microscopes that were capable of 200X magnification

Cell Theory 1838 Mattias Schleiden stated that all plant tissues consisted of cells 1839 Theodore Schwann stated that all animal tissues consisted of cells Each conjectured that there was a nucleus 1858 Rudolf Virchow combined the two ideas and added that all cells come from pre-existing cells, formulating the Cell Theory

Rudolf Virchow 1858 Cell Theory All living things are composed of one or more cells In organisms, cells are the basic units of structure and function. All cells are produced only from existing cells.

Prokaryotic vs Eukaryotic Cells

Prokaryotic Cells primitive, ‘before kernal’ - NO NUCLEUS Lack internal membranes (no “membrane-bound” organelles) Genetic material: single, circular DNA molecule suspended in the cytoplasm Ex. Bacteria (such as Anthrax or E. coli) Microscopic, single-celled organisms Prokaryotic Cells (Bacteria)

Unicellular (one)vs. Multicellular (many) Unicellular: Single-Celled Most common forms of life on Earth. Carry out all functions of Life. Bacteria Amoeba Paramecium

Multicellular Larger organisms. Different cells have specialized functions, together making a complete organism. Human Spider Jellyfish Visit a “Tour of the Cell” at: video

Cell Membrane: “Security Gate” Surrounds the cell Controls movement of materials into and out of cell

Nucleus: Controls the functions of the cell (the brain) Includes the following: Nuclear Envelope (Membrane): Controls movement into and out of the nucleus Nuclear Pore: holes where movement takes place

Nucleus: Nucleolus: Dark area inside nucleus, believed to be for making RNA and ribosomes Chromatin: Genetic Material (DNA) which is organized into structures called chromosomes during cell division.

Cytoplasm: remainder of the contents of the cell consisting of: Cytosol:liquid environment Cytoskeleton: network of protein fibers that supports the shape of the cell and anchors its organelles and serves as a “track” for them to move on. Crisscrosses the cytoplasm

Mitochondria: “Powerhouse” Provides energy for cell. Converts food to usable energy for cell. Have their own ribosomes and DNA.

Golgi Apparatus (Complex): “packaging and distributing center” Stack of membrane-enclosed spaces. Process/Sorts/Packages protein/lipids for distribution within the cell and export out of the cell. Proteins/lipids come from endoplasmic reticulum.

Endoplasmic Reticulum (ER): (Highway) Set of channels…aids in movement of molecules inside the cell. Rough ER: Ribosomes found on surface. Smooth ER: No ribosomes on surface.

Ribosome (4d): (Factory) Makes proteins and is found in the cytosol or on the ER.

Vacuole: “Storage Tanks” Fluid filled sack. Stores water, food molecules, ions and enzymes. Animal cells contain many small vacuoles. Plant cells contain a large central vacuole…we will be talking about this more later…

Lysosomes: “Suicide Sacs/Recycling Centers” Carry enzymes to destroy cellular waste. Break down damaged/worn out cell parts. Engulf/digest targeted molecules Defend cell from invading bacteria/viruses Once thought to be only in animal cells, but exist minimally in plant cells. Membrane protects cell from enzymes.

Plant Cell

Plant Cells: Cell Wall: Gives cells shape and support and provides protection. Found in algae, fungi and most bacteria too. contain all of the previous organelles (except centrioles) as well as:

Plant Cells: Chloroplast: (green) Changes sun’s energy into food. Also in green algae. contain all of the previous organelles (except centrioles) as well as:

Plant Cells: Central Water Vacuole: Single, large water filled vacuole in the middle of the cell. Strengthen cells and provide support for plant. Contains toxins to harm plant predators, waste products and pigment for color (petals). contain all of the previous organelles (except centrioles) as well as:

Animal Cell

Animal Cells contain all of the previous organelles plus: Centrioles: 2 cylindrical organelles (together called a centrosome) Formed by hollow protein fibers called microtubules (part of the cytoskeleton) Produce microtubules that aid in moving chromosomes during cell division. Found in animals and algae only but not in all animal cells. Video tour of cell