Prokaryotes: The Simplest Forms of Life
Prokaryotes: The Simplest Forms of Life
Objectives
-
mount, stain, and observe bacteria cells under a microscope.
-
make a model of a typical prokaryotic cell and explain how each part functions within the cell.
-
relate the structure and function of prokaryotic cells to the common characteristics of living things.
<
Essential Questions
Vocabulary
-
Archaea: Unicellular prokaryotes that have cell walls that do not contain peptidoglycan.
-
Archaebacteria: Kingdom of unicellular prokaryotes whose cell walls do not contain peptidoglycan.
-
Bacteria: The most abundant and most studied group of prokaryotes.
-
Capsule: Including the slime-layer, made of polysaccharides (or proteins) that aid in attachment and protects the cell from dehydration and being engulfed or digested by enzymes. It also sometimes stores nutrients.
-
Cell Wall: Formed from peptidoglycan (polysaccharide and protein), protects the cell from osmotic lysis (taking in too much water and bursting) and gives the cell shape.
-
Cytoplasm: Mostly made of water, this is where all internal structures are found and where all chemical reactions take place.
-
Flagellum: (plural, flagella) A long whip-like attachment made of protein that is used for movement. It originates in the cytoplasm, just below the plasma membrane. Prokaryotes may have one, two, or many flagella.
-
Nucleoid: The central portion of the cytoplasm that contains the circular genetic material contained in the plasma membrane. It is not separated from the cytoplasm by a membrane.
-
Pilus: (plural, pili) A hollow protrusion made of protein. Pili are part of the plasma membrane and aid in attachment to other cells or surfaces, and in sensing the environment. The sex pilus allows the transfer of genetic material during conjugation. Also called fimbria.
-
Plasma Membrane: Phospholipid bilayer imbedded with many proteins that are used in the transport of ions, nutrients, and wastes across the membrane. Also called cell membrane.
-
Plasmid: Small circular double-stranded genetic material. They are transferred to another bacterium during conjugation. Some plasmids carry genes for antibiotic resistance or form toxins.
-
Prokaryote: Single-celled organism that does not contain a nucleus or membrane-bound organelles.
-
Ribosomes: Small inclusions that translate the genetic code into protein.
-
Unicellular: Organisms made up of a single cell.
Duration
Prerequisite Skills
Materials
-
Prokaryote Pictures (S-B-3-1_Prokaryote Pictures.doc)
-
What Do Prokaryotes Look Like? worksheet (S-B-3-1_What Do Prokaryotes Look Like and KEY.doc)
-
Prokaryote Cell (S-B-3-1_Prokaryote Cell.docx)
-
Parts of a Prokaryote worksheet (S-B-3-1_Parts of a Prokaryote Worksheet.doc)
-
Prokaryote Model Gallery Walk and KEY (S-B-3-1_Prokaryote Model Gallery Walk and KEY.doc)
-
Prokaryotic Cell Structures and Functions Chart and KEY (S-B-3-1_Prokaryotic Cell Structures and Functions Chart and KEY.doc).
-
Prokaryotic Review (S-B-3-1_Prokaryotic Review.doc)
-
plain yogurt with live and active cultures
-
beaker
-
distilled water
-
eye dropper
-
methylene blue
-
toothpick
-
light microscopes (one/group), or high-powered light microscopes (if available)
-
slide and slip cover (one/group)
-
prepared slides of prokaryotic cells (if available)
-
non-latex gloves
-
goggles
-
empty water/soda bottles (one/group)
-
resealable plastic bags, sandwich bags, or large non-latex balloons (one/group)
-
yarn, ribbon, and string
-
beads, seeds, and beans
-
straws or coffee stirrers
-
toothpicks
-
glue or hot glue
Related Unit and Lesson Plans
Related Materials & Resources
The possible inclusion of commercial websites below is not an implied endorsement of their products, which are not free, and are not required for this lesson plan.
-
How to Use a Microscope
www.nikon.com/products/instruments/tech/guide/howto/index.htm
-
A Short History of Nearly Everything by Bill Bryson. Broadway Books, 2004.
-
Wet Mounting Instructions
-
Detailed description of the structure and function of a typical bacteria cell.
-
Detailed description of the structure and function of a typical bacteria cell.
-
News story video clip about synthetic bacteria. (2 minutes)
http://abcnews.go.com/Health/Wellness/scientists-create-synthetic-cells/story?id=10708502
-
BBC News story about synthetic bacteria. Discusses how the genome for the bacteria was obtained.