Identifying Cells under the MicroscopeScience 8: Cells, Tissues, Organs, and Organ Systems

Curriculum Outcomes Addressed:• Illustrate and explain that the cell is a living system that exhibits all of the characteristics of life (304-4)• Distinguish between plant and animal cells (304-5)• Explain that it is important to use proper terms when comparing plant and animal cells (109-13)

http://us.123rf.com/400wm/400/400/eraxion/eraxion1006/eraxion100600408/7149016-human-cells.jpg

The word cell comes from the Latin word cella, which means "small room“.

Review: Characteristics of Living Things

The cell theory consists of six characteristics of living things. Anything that has all six of these characteristics is classified as a living thing.

1. Living things are composed of ___________2. Living things reproduce, grow, and ________ themselves3. Living things require ____________4. Living things respond to the ______________5. Living things have a ________________6. Living things produce ______________

Review: Characteristics of Living Things

The cell theory consists of six characteristics of living things. Anything that has all six of these characteristics is classified as a living thing.

1. Living things are composed of cells2. Living things reproduce, grow, and repair themselves3. Living things require energy4. Living things respond to the environment5. Living things have a life span6. Living things produce wastes

During this lesson, we will…

– Learn about the differences between plant and animal cells in more detail (cell size, shape, and organelles)

– View examples of plant and animal cells and their organelles when magnified under a microscope

– Practice identifying microscopic images of plant and animal cells

– Continue to become familiar with the terminology used when talking/writing about cells and their organelles

Plant vs. Animal Cells

• There are a number of differences between plant and animal cells that can be seen when they are viewed under a microscope

• Can you think of any?

Plant vs. Animal Cells

• There are a number of differences between plant and animal cells when they are viewed under a microscope

– Cell size and shape of animal and plant cells differ– Some organelles are found only in one cell type, but

not in both (cell wall and chloroplast in plant cells; flagellum and cilia in animal cells)

– Some shared organelles have different sizes and numbers in plant cells compared to animal cells

Plant vs. Animal Cells under the Microscope

There are some visual differences between cell types…

Plant Cells Animal Cells

Cell Size Large; usually visible under 40X magnification

Smaller than plant cells; usually visible under 100X magnification or greater

Cell Shape Rectangular; more defined Circular; less definedVacuoles Usually have one very

large central vacuole; the vacuole can take up almost 90% of the plant cell volume; stores water

Usually have a number of smaller vacuoles spread throughout cytoplasm; store water, minerals, and waste materials

Cell size and shape differences between plant and animal cells

- Plant cells are usually larger than animal cells - Plant cells are rectangular; animal cells are circular

Plant cell at 400X magnification Animal cell at 400X magnification (Frog blood cells – stained purple)

http://www.danacode.co.il/thecel/cel1/ELODIA400.jpg

Organelle differences between plant and animal cells Plant cell at 400X magnification Animal cell at 1000X magnification - Large central vacuole - Smaller vacuoles throughout - Chloroplast - No chloroplast - Thick outer cell wall - No thick outer cell wall

http://www.franklin.k12.ma.us/~allenc/014E2A6A-0066418D.16/vacuole--plant0.jpg

http://ars.els-cdn.com/content/image/1-s2.0-S1434461011001258-gr14.jpg

Plant vs. Animal Cells Some organelles are not found in both types of cells…

Organelle Type of Cell found in and explanation

Some organelles are not found in both types of cells

Organelle Type of cell found in and explanation

Cell WallFound only in plant cells; the cell wall is the thick outermost layer of plant cells. It supports and protects the cell. It is very rigid, so it does not allow the plant cell to expand or adapt as much as the animal cell is able to.

ChloroplastFound only in plant cells; it contains chlorophyll, which is responsible for converting Carbon dioxide and water into sugar molecules (energy/food) during photosynthesis. Animals cannot make their own food. Chlorophyll is a pigment that gives plants their green colour.

Flagellum/Cilia

Found only in some animal cells (but not in plant cells). These are whip-like and hair-like structures which help the cell to move

Golgi Body and Lysosomes

http://faculty.une.edu/com/abell/histo/golgilys.jpg

Mitochondrion

http://biology.unm.edu/ccouncil/Biology_124/Images/mitochondria.bmp

Rough and Smooth Endoplasmic Reticulum

http://www.zoology.ubc.ca/~berger/b200sample/unit_8_protein_processing/images_unit8/0_300_er.jpg

Nucleus, Nucleolus, and Chromosomes

http://iws.collin.edu/biopage/faculty/mcculloch/1406/outlines/chapter%207/animalcell2.jpg

Organelles Under the Microscope

Helpful Resources

• Interactive 3D Cell and Organelles: http://www.cellsalive.com/cells/3dcell.htm

• Differences between Plant and Animal Cells in more detail: http://www.diffen.com/difference/Animal_Cell_vs_Plant_Cell

• Cell Structures and Functions (detailed presentation): http://www2.hoover.k12.al.us/schools/hhsfc/teachers/dwalker/Documents/Cell%20Organelles.pdf

• Plant and Animal Cell Online Practice Quiz: http://www.quizrevolution.com/ch/a70678/go/plant_and_animal_cells_quiz