Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant...

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Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification

Transcript of Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant...

Page 1: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Cells IntroDefining Life

Cell Theory

Cell Size

Prokaryotic vs. Eukaryotic

Animal vs. Plant

Organelles

Magnification

Page 2: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Defining Life

Does it grow? Does it reproduce? Does it use energy? Does it respond to environmental stimuli? Does it have order? Does it regulate its internal environment? Does it show evidence of evolutionary adaptation?

Page 3: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Cell Theory

All living organisms are composed of cells. Multicellular organisms (example: humans) are composed of

many cells Unicellular organisms (example: bacteria) are composed of

only one cell.

Cells are the smallest unit of life. They are the smallest structures capable of surviving on their own. See previous slide

Cells come from pre-exsisting cells and cannot be created from non-living material. Gooseneck flask experiment

Page 4: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Evidence for Cell Theory

No such thing as spontaneous generation

Pasteur’s experiment

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Cell Size

Surface area of cell responsible for exchange of nutrients and waste products

Volume of cell responsible for cellular functions (e.g. cell respiration)

Page 6: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Volume

Volume determines the amount metabolism in the cytoplasm

Metabolism will require import of precursors

Metabolism will result in the export of secretions

And the export of excretory products

© 2007 Paul Billiet ODWS

Page 7: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Surface area Surface area will determine the exchange of

materials between the cell and its environment

Bigger cells will metabolise more But they will need more surface to support that

metabolism And the sites of metabolism in bigger cells will

be further from the surface of the cell

© 2007 Paul Billiet ODWS

Page 8: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Growing cells

1µm

2µm

3µm

4µm

5µm

6µm© 2007 Paul Billiet ODWS

Page 9: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

How are surface area and volume affected by growth?

11.21.5236

216125642781

2161509654246

654321

SA/V

Volume / µm3

Surface area / µm2

Size / µm

© 2007 Paul Billiet ODWS

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Comparing Surface Area and Volume changes

0

100

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0 1 2 3 4 5 6 7 8 9 10

Size / µm

Surface areaVolume

© 2007 Paul Billiet ODWS

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Surface Area:Volume Ratio

0

1

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Size / µm

SA

/V

© 2007 Paul Billiet ODWS

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Solving the problem

Bigger cells have a greater metabolism than smaller cells

BUT bigger cells have a proportionally less surface for exchange

How to increase surface area with increasing size?

© 2007 Paul Billiet ODWS

Page 13: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Throw out extensions

Microvilli of small intestine epithelium

© copyright 2001 Gwen V. Childs, Ph.D., University of Arkansas for Medical Sciences

Page 14: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Flatten into a thin film

Chick blastodisc© Developmental Biology Online © Developmental Biology Online

Page 15: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Divide the cytoplasm into smaller volumes

Early human embryos

Zygote

8-cell Embryo

© Reproductive Medicine and Fertility Center

Page 16: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Multicellular organisms show the same adaptations

Flowering plants have an extensive, branched rooting system to absorb water and minerals

© Illinois Enviromental Protection Agency© Text 2007 Paul Billiet ODWS

Page 17: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Multicellular organisms show the same adaptations

Mammals have a long small intestine with internal folding to absorb digested food

lithograph plate 20th U.S. edition of Gray's Anatomy of the Human Body, originally published in 1918. This image is in the public domain because its copyright has expired

© Text 2007 Paul Billiet ODWS

Page 18: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Prokaryotic vs. Eukaryotic

Prokaryotic cells No nucleus Circular DNA No histone proteins No membrane bound organells Simple ribosomes

Eukaryotic cells Nucleus Linear DNA (chromosomes) Histone proteins Membrane bound organelles Complex ribosomes

Page 19: Cells Intro Defining Life Cell Theory Cell Size Prokaryotic vs. Eukaryotic Animal vs. Plant Organelles Magnification.

Animal vs. Plant

In animals but not plants: In plants but not animals:

Lysosomes Cell Wall

Centrioles Centrosomes

Flagella Chloroplasts

Central Vacuole

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Organelles

http://library.thinkquest.org/12413/structures.html

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Magnification

Magnification = Size of image (Units must be the same)Actual size

If a red blood cell has a diameter of 8 μm and a student shows it with a diameter of 40 mm in a drawing, what is the magnification of the drawing?

A.× 0.0002B.× 0.2C.× 5D.× 5000