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Antibiotic Resistance:
Case Study



UNIT 2: Cell Structure and Function

What you should know:

All living things are composed of cells. Cells are the basic units of life and all tissues and organs are composed of cells. They are so small that they must be viewed with a microscope. There are different types of cells. Cells can either be eukaryotic or prokaryotic. Eukaryotic cells have a nucleus and membrane bound organelles. Plant and animal cells are eukaryotes. Plant cells are generally a square shape while animal cells are usually circular. Plant cells and animal cells have evolved different organelles to perform specific functions. Plant cells have chloroplasts, a cell wall and a central vacuole. Animal cells lack these three organelles. Plant cells have chloroplasts because they make their own food. Plant cells have a cell wall so that they do not burst when the central vacuole fills up with water. Prokaryotes do not have a nucleus, and lack membrane bound organelles. They are the oldest cells on earth. Bacteria are prokaryotes. Prokaryotes often move using special structures such as flagella or cilia.

Cells have many structures inside of them called organelles. These organelles are like the organs in a human and they help the cell stay alive. Each organelle has it’s own specific function to help the cell survive. The nucleus of a eukaryotic cell directs the cell’s activities and stores DNA. Eukaryotes also have a golgi apparatus that packages and distributes proteins. Mitochondria are the power house of the cell and provide the cell with energy. Both plant and animal cells have mitochondria. Lysosomes are like the stomach of the cell. They contain enzymes that digest the cell’s used parts. All of the cell’s organelles must work together to keep the cell healthy.

The cell membrane is the protective barrier that surrounds the cell and prevents unwanted material from getting into it. The cell membrane has many functions, but one main function that it has is to transport materials (salts, electrolytes, glucose and other necessary molecules) into the cell to support necessary life functions. Not only does the membrane let molecules into the cell, but it also lets wastes such as carbon dioxide out of the cell. The cell membrane is made up of a phosholipid bilayer. Each phopholipid contains a hydrophilic, or water loving head and ahydrophobic, or water fearing tail. These properties that the phospholipids have and the specific orientation they are arranged in provide the cell with an selectively permeable barrier.

How you make sense of things:

Inital EPE before unit

Observations you make
in your daily life:
Patterns you notice:
Explanations for the patterns:
Bacteria are single celled.

When you look at living things under a microscope you can see cells.

Tissues and organs are composed of cells. Cells are the basic units of life.


Goal EPE after unit

Observations you make during lab:
Patterns you notice in your data:
Explanations for the patterns:
Cell Membrane Activity
Observations that large candy can not get through the plastic bag.

Observations that the only way to get the candy into the plastic bag without putting a hole in the cell membrane is to get the candy into a vesicle closed off with a rubber band, rubber band the cell membrane and cut in between the two rubber bands.

Plant and Animal Cell Lab
Onion cells have a square shape.

Cheek cells have a round shape.

Both onion cells and cheek cells have a nucleus, cell membrane, and cytoplasm.

Cell Membrane Activity
Large molecules can get into cells when the cell membrane engulfs the molecule and a vesicle breaks away from the cell membrane.

Large molecules can only get out of cells when they are sent in a vesicle to the cell membrane, fuse with the membrane and are released to the outside of the cell.

Plant and Animal Cell Lab
Plant cells have chloroplasts, a cell wall, and a central vacuole that animal cells do not have.

Cell Membrane Activity

Plant and Animal Cell Lab
Different cell types have evolved specialized organelles to perform specific functions.


What you should be able to do:

1. You will be able to differentiate between plant cells and animal cells.
2. You will be able to explain the differences between prokayotes and eukaryotes.
3. You will be able to explain how cells transport large molecules across the cell membrane.
4. You will be able to identify the function of the organelles in a cell.