User:Starchildmom/Cell Unit Study

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Basic Cells Unit Study[edit]


Introduction:

For this unit we will be using the Usborne Internet-Linked Science Encyclopedia (please check your library before buying) as our initial reference material. I will also be including links to Wikipedia entries for both the English and Simple English (easier reading level) versions when available. The Wikipedia entries can be used as an alternative main source for this unit. The basic structure of this unit is to first do some background research, followed by the activities that will be used to create the unit folder, and finally some laboratory activities which will be recorded and added to the unit folder. The general level for this unit is based on a year 5 (Logic Stage) science program following a classical trivium similar to many popular commercial homeschool curriculum. One big difference in our studies (other than we are Open Source and Creative Commons Licensed, i.e. Free) , is that our units embrace technology. To really take advantage of what this unit can offer a good Internet connection is a must. At the present some of the critical information, diagrams, and downloads needed to complete this unit will be in the form of links to those tools on other sites. While most of those sites will have some sort of commercial aspect, all of the resources needed to complete this unit will be part of their no-cost offerings. I hope as time goes on to be able replace those links with resources developed specifically for distribution with this unit. That is part of where the Open Source aspect enters into the big picture. If you, a user, wish to contribute to a unit by creating one of those resources (or even writing your own unit following our format) feel free to do so. You may redistribute it yourself (following the Creative Commons licensing terms) or submit to me for inclusion in the main distribution of this unit (upon approval).



Cell Structure Unit Study


Goals:

To learn the basic structures, types, and processes of cells.


Background Research:

Choose your main resource, or try them all!

Usborne Science Encyclopedia : Read pages 250-251 and 298-299

Wikipedia: Cellular Biology Plant Cells Animal Cells Eukaryotes Prokaryotes Mitosis Meiosis


Introduction to Cellular Biology

Cells are the basic building blocks of life. They are like organic Legos. Each one has a similar basic structure, but the subtle differences (color, number of connectors) make each Lego perform a little differently. Sometimes, even a single block can be enough to form the entire structure. The same is true with cells. There are unicellular organisms and multicellular organisms, simple cells, and complex cells, but the basics of a cell are always there.

The study of cells is called cellular biology, or cytology. A scientist who specializes in cellular biology is called a cytologist. This study includes their physical properties such as their structure and the organelles they contain, their environment and interactions, their life cycle, division and function and eventual death. Knowing the composition of cells and how cells work is important to all of the biological sciences.




Activity1: Vocabulary

Make a 16 word vocabulary book (Big Book of Books p. 97). Add the following words on the top flaps. Look up their definitions in Webster's Student Dictionary online and write them below the flaps. You will add more words later.

  1. organic
  2. unicellular
  3. multicellular
  4. organelle
  5. organism
  6. membrane


Cell History

Cells were discovered by Robert Hooke. He used a microscope to look at organisms in 1665. He named cells after the Latin word cella which means a room. He did this because he thought cells looked like small rooms. Three German biologists - Schleiden, Schwann and Virchov - figured out three rules about all cells: 1.all living things are made of cells 2.the cell is the basic unit of structure and function in all organisms. 3.every cell comes from another cell that lived before it.



Activity 2: Cell Rules & History

Make a Three Pocket Book (Big Book of Science p.20). Make three cards, one for each pocket. On each card write on of the rules above. At the top of the inside write “3 Rules About Cells”. On the bottom flaps, first write “Figured out by German Biologists” near the top edge, below that write the name of one of the biologists on each pocket. On the left outer flap write “Robert Hooke.” On the right outer flap write “discovered cells by using a microscope in 1665.” This should be very neat. Think of it like an art project and make it as decorated (within the theme) as you like. The center-back outer flap will be glued into the final unit study folder, so do not decorate that part.


Basic Cell Structure

In biology, the cell is the basic structure of organisms. All cells only come from other cells. The outside of the cell is a cell membrane. Inside some cells, some parts of the cell stay separate from other parts by membranes. These separate parts are called organelles (like small organs.) They have different functions in the cell (do different work.) Some of these are ribosomes, nucleus (where DNA is), and mitochondria. Kinds of cells

There are two basic kinds of cells: prokaryotic cells and eukaryotic cells.

Prokaryotes are simple cells. Bacteria are types of prokaryotes. They are very simple cells that do not have a nucleus or any other membrane-bound cells found in more complex cells. In order to function, prokaryotic cells must still have certain features. A nucleoid region containing the DNA. This region is not contained in a membrane, and, therefore is not a nucleus. Ribosomes to translate the DNA code into the proteins needed. An outer membrane to hold everything together Some prokaryotes also have cell walls, or flagella (to help them move around)

Eukaryotes are less simple cells. All eukaryotic cells have a nucleus, and may have membrane bound organelles. Most multicellular organisms are made up of eukaryotic cells, although there are unicellular (single-celled) eukaryotes. Plant and animal cells are eukaryote.



Prokaryotic Organisms

All prokaryotic organisms are unicellular.

Most prokaryotic organisms are bacteria. All bacteria (or "one bacterium") are very small organisms (living things). They are so tiny they can only be seen with a microscope. Bacteria are formed with very few cells. Many of them have only one cell. This kind of organism is called a unicellular organism. Bacteria are among the oldest living organisms on Earth. There are more bacteria than any other living organism on the planet. Most bacteria live in the ground or in water, and many live inside of other living organisms. Some bacteria can cause diseases in other organisms, but others are good. A bacterium reproduces (creates more bacteria) by dividing itself into two new "child" bacteria.

Bacteria under the microscope


Kinds of eukaryotic organisms

There are two kinds of eukaryotic organisms: multicellular and unicellular.

Unicellular

A paramecium Unicellular organisms are made of one cell. Examples of unicellular organisms are: Amoeba Paramecium Unicellular organisms live without other cells to help them. So the cell does all things that it needs to live. Each cell: eats moves respires (uses oxygen to make sugar into energy) gets rid of waste reproduce (make more of itself) senses its environment


Multicellular

Multicellular organisms are made from many cells. This can be a small number of cells, or millions of cells. All plants and animals are multicellular organisms. The cells of a multicellular organism are not all the same. They have different shapes and sizes, and do different work in the organism. The cells are specialized. This means they do only some kinds of work. By themselves, they cannot do everything that the organism needs to live. They need other cells to do other work. They live together, but cannot live alone.


Epithelial Cells

Activity 3: Compare and Contrast Prokaryotic and Eukaryotic Cells

Create a three-tab Venn diagram book (Big Book of Science p.17). On the flaps make a Venn diagram comparing and contrasting the two types of cells. Inside, under the appropriate flap, list some types of organisms that have that kind of cell. On the outside sections (will be cover flaps when closed) that corresponds to each cell, draw a colorful diagram of that type of cell.


Plant Cells

Plant cells are quite different from the cells of the other eukaryotic organisms. Their distinctive features are: A large central vacuole (space enclosed by a membrane), which is filled with fluid and helps the cell keep its shape. A cell wall made up mostly of cellulose . The cell wall is thick and rigid, supporting the cell. The cell walls of multiple cells bond together to form the structure of the plant.

Chloroplasts that contain chlorophyll, the pigment that gives plants their green color and allows them to perform photosynthesis.

Plants lack centrioles that are present in animal cells. Like other eukaryotic cells, plant cells typically also have a nucleus, containing most of the cell's DNA, and mitochondria, the 'power plants' of the cell.


Animal Cells

An animal cell is a form of eukaryotic cell. Many tissues in animals are eukaryotic. The animal cell is different from other eukaryotes, most notably plant cells, as they lack cell walls and chloroplasts, and they have smaller vacuoles. Due to the lack of a rigid cell wall, animal cells appear to be circular (though are often deformed by surrounding cells) under microscopes - in three dimensions the cells are normally spherical.

Activity 4: Plant & Animal Cell Diagrams

Color and label the diagrams below. Cut them out and glue onto separate larger pieces of colored paper for a border.