Introduction to Cell Biology

While we watch the YouTube clip, take notes about the scientists involved in the discovery of cells. Note the dates, people involved, and their particular discoveries.

http://www.youtube.com/watch?v=dscY_2QQbKU&feature=related

The Discovery of the Cell

On a left-side sheet of notebook paper, using your notes from the video, along with your textbook, create a timeline leading up to the cell theory. Illustrate each discovery (use color). Leave enough space between events to add details later.

The Discovery of the Cell—Timeline

Hooke-English scientist who was the first to see a dead cell while viewing cork under a microscope.Coined the term “cell”.

Leeuwenhoek- Dutch scientist who was first to see living cells in a drop of pond water.Considered the “Father of Microscopy”.

The Discovery of the Cell

Schleiden- German botanist who stated all plants are composed of cells.

Schwann-German zoologist who stated all animals are composed of cells.

Virchow-German physician who saw bacterial cells dividing under microscope.

The Discovery of the Cell

1) All living organisms are composed of one or more cells

2) Cells are the basic units of structure and function in an organism

3) Cells come only from the reproduction of existing cells

Which of the 7 characteristics of life do the parts of the Cell Theory match up with?

The Cell Theory—The cell as the basic unit of life

Size Most plant and animal cells are about 10-50

micrometers (µm) in diameter. Most bacterial cells are about 1-10 µm in diameter.

Cells are limited by their surface area to volume ratio.

As a cell grows, its volume increases much faster than its surface area.

http://learn.genetics.utah.edu/content/begin/cells/scale/

Why is surface area so important to determining the health and survival of a cell?

Cell Diversity

Surface Area to Volume Ratio Everything that the cell needs or has to

get rid of has to go through the cell membrane, the amount of which relates to the surface area.

The amount of food needed or waste produced depends on the volume.

As a cell gets bigger there will come a time when its surface area is insufficient to meet the demands of the cell's volume and the cell stops growing.

Cell Diversity

Shape Cells come in a variety of shapes. The diversity of form (structure)

reflects a diversity of function. How do the shapes of nerve, blood,

and skin cells suit their function?

Cell Diversity

Plasma membrane Covers cell surface and acts as a boundary

between inner contents of a cell and its environment

Cytoplasm Region of the cell inside the membrane Includes fluid, cytoskeleton, and all

organelles (except the nucleus) Control center

Region containing DNA which regulates cell construction and other processes

Common Cell Structures

Prokaryotes Cells without a

nucleus or membrane bound organelles (MBOs)

Example: E. coli

Two Basic Cell Types

Eukaryotes Cells with a nucleus and membrane

bound organelles (MBOs) Examples: Human cheek cells, plant

cells

Two Basic Cell Types

Colonies Colonial organisms are collections of

genetically identical cells that live together in a group.

Not truly multicellular because few activities are coordinated.

Cellular Organization

True Multicellularity Cells of multicellular organisms are

organized further into tissues, organs, and organ systems, which have their own specific purposes.

Cellular Organization