Cells

Scientists have discovered that there are two different types of cells:

Prokaryotic

Eukaryotic

Prokaryotic Cells

Cells that do not have a nucleus or other organelles with membranes around them.

Bacteria are examples of prokaryotic cells.

Eukaryotic Cells

A eukaryotic cell has a nucleus and other organelles with membranes around them.

Animal, plant, fungi and protista cells are eukaryotic.

Cell StructureOf Eukaryotic Cells

Images, text and information found at: http://www.vilenski.org/science/safari/cellstructure/cellmembrane.html and google images.

Cell MembraneThe cell membrane is a structure that forms the outer boundary of the cell and allows only certain materials to move into and out of the cell.

Food, oxygen and water move into the cell through the membrane. Waste products also leave through the membrane.

The cell membrane allows only certain materials to move in and out of the cell

Cell WallThe cell wall is a rigid structure

outside the cell membrane that supports and protects the cell (for plants, fungi, and some protists and bacteria).

The cell wall is made of tough cellulose fibers and other materials made by the cell. Note: fungal cell walls contain chitin instead of cellulose.

The cell wall is a rigid structure outside membrane the cell

NucleusThe largest organelle in the cytoplasm

of a eukaryotic cell is usually the nucleus, a structure that directs all the activities of the cell.

The nucleus is like a manager who directs everyday business for a company and passes on information to new cells. The nucleus contains genetic blueprints (Chromosomes) for the operations of the cell.

The Manager, Mr. Nucleus

CytoplasmCytoplasm is the gel-like material inside

the cell membrane and outside the nucleus.

Cytoplasm contains a large amount of water and many chemicals and structures that carry out the life processes in the cell.

These structures that the cytoplasm contains are called organelles.

Unlike a gelatin dessert, however, cytoplasm constantly moves or streams.

Cytoplasm is the gel-like material inside the cell (but unlike gelatin it does flow)

MitochondriaCells require a continuous supply of

energy.

Mitochondria are organelles where food molecules are broken down and energy is released. The energy is then stored in other molecules that can power cell reactions easily.

Just as a power plant supplies energy to a business, mitochondria release energy for the cell. 

The mitochondria

are where energy is released

ChloroplastsChloroplasts contain a green

pigment called chlorophyll. This is what makes plants green.

Chloroplasts take in sunlight, water and carbon dioxide to make oxygen and sugar (a form of food). This process is called photosynthesis. A plant's chloroplasts

convert light energy into chemical energy

This photograph of elodea (a waterplant) has many green dots visible within the cells. These are the chloroplasts.

VacuoleRemember the last vacation

you took? Your suitcase temporarily stored your clothes. Within a cell, a vacuole fills a similar role as a temporary storage space for the cell.

Vacuoles store water, food, pigments, waste or other materials.

Vacuoles are large in plant cells and small in animal cells. Vacuoles can also be found in fungi and protists.

Like your suitcase, a vacuole is a temporary

storage space for the cell.

Chromosomes• Packaged DNA in the nucleus• DNA is so long it needs to be

folded in a special manner in order to fit inside the cell nucleus

• The DNA is the instruction manual for the organism, controlling the actions of the cells and passing information from one generation to the next (inheritance)

• This is similar to having words organized in sentences, paragraphs, and chapters in a book