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CELL STRUCTURE AND FUNCTION

(Cells : Up Close and Personal)

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IMPORTANT SCIENTISTSTHAT STUDIED CELLS• Leeuwenhoek :

Invented the microscope

• Hooke :

Looked at cork and named “cells”

• Schwann :

Determined that all animals were made of cells

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More Important Scientists

• Schleiden :

Determined that all plants are made of cells

• Virchow :

Determined that all cells come from pre-existing cells (cells produce

more cells)

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The Cell Theory

• 1. All living things are made of cells(Schleiden and Schwann)

• 2. Cells are the structural and functional units of life

• 3. All cells come from pre-existing cells(Virchow)

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Common Cell Structures

• All cells have the following in common :

1. cytoplasm (internal fluid)

2. cell membrane (not all cells have cell wall)

-regulates what enters/exits cell

3. genetic material (DNA or RNA) ; not all cells have a nucleus

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Why Cells are Small

Cells are small because of a surface area–to-volume ratio problem. Cells need a large surface area to allow nutrients and raw materials to enter the cell through the cell membrane and allow wastes to be removed from the cell through the cell membrane.

The problem comes from the fact that as an object gets larger, its volume (the interior of the cell) becomes larger faster than the surface area (cell membrane) does.

Check out the web site below for a good illustration and a better explanation of this concept.

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Prokaryotic Cells vs. Eukaryotic Cells

• Prokaryotic Cells = - cells of bacteria and their relatives- have genetic material but no nucleus- do not have membrane-bound organelles

• Eukaryotic Cells =- all cells of living things except bacteria- have a nucleus that holds genetic

material- have membrane-bound organelles (such as mitochondria, ER, Golgi, chloroplasts, lysosomes, etc.)

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Prokaryotic & Eukaryotic Cells Diagram

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Plant Cells Vs. Animal Cells

• Plant Cells Have :

- Plastids

(chloroplasts)

- Cell Walls (and cell

membranes)

- Large Vacuole• Animal Cells Do Not

Have These.

• Animal Cells Have :

- Centrioles

(for cell reproduction)

- Cell Membrane Only

(no cell walls)• Plant Cells Do Not

Have These.

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Plant & Animal Cell Diagrams

http://micro.magnet.fsu.edu/cells/plantcell.html

Plant Cell Diagram Animal Cell Diagram

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Common Organelles of Cells• Nucleus =

- contains chromosomes for heredity- controls cell’s activities- “brain” of the cell

• Nucleolus =- inside the nucleus- makes ribosomes

• Ribosomes =- found either in cytoplasm or on E.R.- sites for protein synthesis

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Cell Organelles (cont.)• Mitochondria =

- “powerhouse” of the cell- site for cell respiration (breaking

down glucose for energy)• Endoplasmic Reticulum (E.R.) =

- transportation of materials in cell- “smooth” or “rough” ER

• Golgi Apparatus = - packaging, modifying, shipping of

materials in cell

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Cell Organelles (cont.)• Lysosomes =

- contain digestive enzymes - “suicide sacs”

• Vacuoles =- “bags” containing H2O and

dissolved materials (solutes) in the cell• Chloroplasts =

- sites for photosynthesis in plants- CO2 + H20 Glucose (sugar)

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Some Cell Types

nerve cell sperm cells red blood cells muscle cells

cheek cellsplant leaf cells potato cells

w/ starch plant stem cells

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Guess What These Are !

Click Here to Find Name

Click Here to Find Name

Click Here to Find Name

Click Here toEnd Presentation

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This is a mitochondria !!

Click to Return to Pictures

Click to End Presentation

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This is a Chloroplast !!

Click to Return to Pictures

Click to End Presentation

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This is a Nucleus !!Click to Return

to PicturesClick to End Presentation

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THE

END(This has been an EJ.McM. Presentation)

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