The document summarizes key concepts about cell structure and function. It describes the early discoveries of cells by Hooke, van Leeuwenhoek, Schleiden, and Schwann which led to the development of the cell theory stating that all living things are made of cells. It then defines cells and describes the two main types - prokaryotic and eukaryotic. The structures and organelles of typical plant and animal cells are outlined, including the cell membrane, cell wall, nucleus, cytoplasm, mitochondria, chloroplasts, and other organelles. The processes of diffusion, osmosis, and concentration gradients that regulate movement of molecules in and out of cells are also summarized.

1. Chapter 7: Cell
Structure
& Function
http://koning.ecsu.ctstateu.edu/cell/cell.html

2. Discovery of Cells
• Robert Hooke (1600’s) discovered “little
chambers” (cells) in cork plant
• Anton van Leeuwenhoek (1600’s)used
microscope to view living things in pond
water. Saw things swimming around!

3. Discovery of Cells, cont.
• Matthias Schleiden (1838) concluded
plants made of cells
• Thoedor Schwann (1839) concluded all
animals made of cells

4. Cell Theory
1. All living things are made up of cells.
2. Cells are the smallest working units of all
living things.
3. All cells come from preexisting cells
through cell division.

5. Definition of Cell
A cell is the smallest unit that is
capable of performing life
functions.

6. Examples of Cells
Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria

7. Two Types of Cells
•Prokaryotic
“pro-” means “before” (like “pre”)
“karyon” means “nut” or kernel”
No nucleus
•Eukaryotic
“eu-” means “true”
Has nucleus

8. Prokaryotic
• Do not have
organelles
surrounded by
membranes
• Few internal
structures
• One-celled
organisms,
Bacteria
http://library.thinkquest.org/C004535/prokaryotic_cells.html

9. Eukaryotic
• Contain organelles surrounded by membranes
• Most living organisms
Plant Animal
http://library.thinkquest.org/C004535/eukaryotic_cells.html

10. “Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif

11. http://waynesword.palomar.edu/images/plant3.gif
“Typical” Plant Cell

12. Eukaryotic
Cell Parts
Organelles

13. Surrounding the Cell

14. Cell Membrane
• Outer membrane of cell
that controls movement
in and out of the cell
• Double layers of fat
“”phospholipid bilayer”
http://library.thinkquest.org/12413/structures.html

15. Cell Wall
• Most commonly found
in plant cells &
bacteria & fungi
• Supports & protects
cells
• Made of carbohydrate
http://library.thinkquest.org/12413/structures.html

16. Inside the Cell

17. Nucleus
• Directs cell activities
• Separated from cytoplasm by nuclear
membrane
• Contains genetic material - DNA

18. Nuclear Membrane
• Surrounds nucleus
• Made of two layers
• Openings allow
material to enter and
leave nucleus
http://library.thinkquest.org/12413/structures.html

19. Chromatin
• Form DNA takes
most of the time.
• Like spaghetti
• Made of DNA
wrapped up
w/proteins

20. Chromosomes
• In nucleus
• DNA wrapped up tight
by proteins called
“histones”
• Contain instructions
for traits &
characteristics
http://library.thinkquest.org/12413/structures.html

21. Nucleolus
• Inside nucleus
• Contains RNA to build
proteins
http://library.thinkquest.org/12413/structures.html

22. Cytoplasm
• Gel-like mixture
• Surrounded by cell membrane
• Contains hereditary material in
prokaryotes

23. Ribosomes
• Each cell contains
thousands
• Make proteins
• Found on
endoplasmic
reticulum & floating in
the cytoplasm
http://library.thinkquest.org/12413/structures.html

24. Endoplasmic Reticulum
• Moves materials around
in cell
• Smooth type: lacks
ribosomes
• Rough type (pictured):
ribosomes embedded in
surface
http://library.thinkquest.org/12413/structures.html

25. Mitochondria
• Produces energy through
chemical reactions –
breaking down fats &
carbohydrates
• Controls level of water and
other materials in cell
• Recycles and decomposes
proteins, fats, and
carbohydrates
http://library.thinkquest.org/12413/structures.html

26. Golgi Bodies
• Protein 'packaging
plant'
• Move materials within
the cell
• Move materials out of
the cell
http://library.thinkquest.org/12413/structures.html

27. Lysosome
• Digestive 'plant' for
proteins, fats, and
carbohydrates
• Transports undigested
material to cell
membrane for removal
• Cell breaks down if
lysosome explodes
http://library.thinkquest.org/12413/structures.html

28. Vacuoles
• Membrane-bound
sacs for storage,
digestion, and waste
removal
• Contains water
solution
• Help plants maintain
shape
http://library.thinkquest.org/12413/structures.html

29. Chloroplast
• Usually found in plant
cells (not in animal)
• Contains green
chlorophyll
• Where
photosynthesis takes
place
http://library.thinkquest.org/12413/structures.html

30. Centrioles
• Used during animal
cell division (not
present in plant &
most other cells)

31. Prokaryotic Cells
• Ribosomes
• DNA or RNA
• cytoplasm

32. Cell Boundaries
• Cell Membrane
1. Controls what
goes in & out
2. Support &
protection
• Cell Wall
1. Support &
protection

33. Diffusion through Cell
Boundaries
• Every cell lives in a
liquid environment
• Membrane controls
movement of
dissolved
molecules back &
forth (in & out of
cell)
• (Remember a
solution contains a
– Solvent: the
substance that
dissolves the other
stuff (often water)
– solute: the
substance that gets
dissolved (salt,
sugar, ions, etc.)

34. Concentration of Solutions
• The greater the ratio of solute to solvent,
the higher the concentration.
• Ex:
• Solution #1: dissolve 5 g of salt in 1L of
water. Concentration= 5g/L
• Solution #2: dissolve 10 g of salt in 1L of
water. Concentration=10g/L

35. Diffusion
• In solution, particles move
constantly, colliding & spreading out.
• Diffusion is the movement of
particles from area of greater to
lesser concentration (b/c of random
motion.)
• Requires no energy to move
substances across a membrane (b/c
moved by random motion)

36. Equilibrium
• When solute concentration is equal
throughout the solution

37. Osmosis
• The diffusion of water through a
membrane
• Some molecules are too large to move
through a membrane

38. How Osmosis Works
see Fig 7-15 on p 185
• If there is a selectively permeable
membrane separating 2 solutions
w/differing concentrations of solute,
• Water will move from the side where it is in
greater concentration to where it is in
lesser concentration. (R to L in picture)

39. Concentration of Solutions
• Isotonic: when the
concentration of
particles is the
same on both
sides of membrane
• Hypertonic: “above
strength”- the
stronger of the 2
solutions (L side)
• Hypotonic: “below
strength”- the less
concentrated of the
2 solutions (R side)

40. How Osmosis Works in Cells
see p 186 of text, Fig 7-16
• Isotonic: Cell
maintains its shape
• Hypertonic