The theory and characteristics

Domains and Kingdoms  3 Domains:  Bacteria  Archaea  Eukarya

How are organisms classified (sorted) into domains and kingdoms?  Classified according to:  Cell type  Ability to make food  Number of cells in their bodies

Prokaryotes  Take the word apart (dissect it):  Pro = before  Kary = cell nucleus So NO NUCLEUS

Prokaryotes  Bacteria AND Archaea:  Unicellular  Prokaryotes  Can be either autotrophs or heterotrophs

So what’s the difference?  Archaeans are different from Bacteria in: 1. Structure 2. Chemical makeup

Eukaryotes  Dissect the word:  Eu = true  Kary = cell nucleus  So TRUE NUCLEUS

Eukaryote kingdoms:  Protists  Fungi  Plants  Animals

What do the kingdoms of Eukarya have in common?  They are eukaryotes. That’s it.

So, we need to know more about cells!

3 Parts of the Cell Theory 1. All living things are made of cells.

2. The cell is the basic units of structure and function in living things. Cells are the basic building blocks of life.

3. All cells come from pre-existing cells.

Who came up with this theory? 1. Schleiden (circa 1838) All plants are made of cells! Onion skin cells

Who came up with this theory? 2. Schwann All animals are made of cells! Human red blood cells

Who came up with this theory? 3. Virchow All cells come from pre-existing cells!

Quick Review of Cell Theory What are the 3 parts of the cell theory? 1. All living things are made of cells. 2. Cells are the basic units of structure and function in all living things. 3. All cells are produced from other cells.

How big are cells?  Microscopic (mostly)  Measured in microns µm  (micrometers).  A µm is one millionth of a meter =  m = one thousandth of 1 mm.

How big are cells?  Largest cell on the human body = ovum  Size=  1000 µm in diameter (1 mm)

How big are cells?  Smallest cell in the human body = sperm cell.  Size= 5.1 µm head

How big are cells?  Human red blood cell = 8 µm in diameter

How big are cells? Smallest free-living cell = Mycoplasma genitalium Size = 0.2 to 0.3 µm

How big are cells?  Bacteria e.g. Eschericia coli (aka E.coli)  Size=1 µm by 3 µm

How big are cells?  Largest cell with a metabolism = Chaos chaos Size=1-5 mm in length.mm common name = Giant Amoeba Chaos diffluens, is an amoeba closely related to the giant amoebaeamoebagiant

How big are cells?  Largest cell = yolk of an ostrich egg

How can we study cells? Problem: They are microscopic! Solution: Use a microscope!

Types of Microscopes 1. Compound light microscope  Light passes through lenses to magnify image up to 1000X  Can observe living cells

Types of Microscopes 2. Electron microscope  Uses a beam of electrons to magnify image > 1000X  Kills cells being observed

Image from Electron Microscope

Common features of all cells Small size – allows materials to move via diffusion

Diffusion  Diffusion = process by which molecules move from levels of high concentration to levels of low concentration until equilibrium is reached

Diffusion

Common features of all cells 1. Cell Membrane – selectively permeable (lets some things in and out)

Common features of all cells 2. Cytoplasm – semi-fluid material in which cell organelles float

Common features of all cells 3.Contains DNA – a nucleic acid that contains genetic information (like blueprints)

Common features of all cells 4. Cytoskeleton – proteins that support the cell (Microtubules & microfilaments)

Common features of all cells 5. Ribosomes – make proteins

Bibliography         Development/Ostrich/Ostrich/Ostrich-15.html       

Bibliography   Google Image Result for      