Title: Chapter 7: Cell Structure
1Chapter 7 Cell Structure Function
http//koning.ecsu.ctstateu.edu/cell/cell.html
2Discovery of Cells
- Robert Hooke (1600s) discovered little
chambers (cells) in cork plant - Anton van Leeuwenhoek (1600s)used microscope to
view living things in pond water. Saw things
swimming around!
3Discovery of Cells, cont.
- Matthias Schleiden (1838) concluded plants made
of cells - Thoedor Schwann (1839) concluded all animals
made of cells
4Cell 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.
5Definition of Cell
- A cell is the smallest unit that is capable of
performing life functions.
6Examples of Cells
Amoeba Proteus
Plant Stem
Bacteria
Red Blood Cell
Nerve Cell
7Two Types of Cells
- Prokaryotic
- pro- means before (like pre)
- karyon means nut or kernel
- No nucleus
- Eukaryotic
- eu- means true
- Has nucleus
8Prokaryotic
- Do not have organelles surrounded by membranes
- Few internal structures
- One-celled organisms, Bacteria
http//library.thinkquest.org/C004535/prokaryotic_
cells.html
9Eukaryotic
- Contain organelles surrounded by membranes
- Most living organisms
Plant
Animal
http//library.thinkquest.org/C004535/eukaryotic_c
ells.html
10Typical Animal Cell
http//web.jjay.cuny.edu/acarpi/NSC/images/cell.g
if
11Typical Plant Cell
http//waynesword.palomar.edu/images/plant3.gif
12Eukaryotic Cell Parts
13Surrounding the Cell
14Cell 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.htm
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15Cell Wall
- Most commonly found in plant cells bacteria
fungi - Supports protects cells
- Made of carbohydrate
http//library.thinkquest.org/12413/structures.htm
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16Inside the Cell
17Nucleus
- Directs cell activities
- Separated from cytoplasm by nuclear membrane
- Contains genetic material - DNA
18Nuclear Membrane
- Surrounds nucleus
- Made of two layers
- Openings allow material to enter and leave
nucleus
http//library.thinkquest.org/12413/structures.htm
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19Chromatin
- Form DNA takes most of the time.
- Like spaghetti
- Made of DNA wrapped up w/proteins
20Chromosomes
- In nucleus
- DNA wrapped up tight by proteins called
histones - Contain instructions for traits characteristics
http//library.thinkquest.org/12413/structures.htm
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21Nucleolus
- Inside nucleus
- Contains RNA to build proteins
http//library.thinkquest.org/12413/structures.htm
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22Cytoplasm
- Gel-like mixture
- Surrounded by cell membrane
- Contains hereditary material in prokaryotes
23Ribosomes
- Each cell contains thousands
- Make proteins
- Found on endoplasmic reticulum floating in the
cytoplasm
http//library.thinkquest.org/12413/structures.htm
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24Endoplasmic Reticulum
- Moves materials around in cell
- Smooth type lacks ribosomes
- Rough type (pictured) ribosomes embedded in
surface
http//library.thinkquest.org/12413/structures.htm
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25Mitochondria
- 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.htm
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26Golgi Bodies
- Protein 'packaging plant'
- Move materials within the cell
- Move materials out of the cell
http//library.thinkquest.org/12413/structures.htm
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27Lysosome
- 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.htm
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28Vacuoles
- Membrane-bound sacs for storage, digestion, and
waste removal - Contains water solution
- Help plants maintain shape
http//library.thinkquest.org/12413/structures.htm
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29Chloroplast
- Usually found in plant cells (not in animal)
- Contains green chlorophyll
- Where photosynthesis takes place
http//library.thinkquest.org/12413/structures.htm
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30Centrioles
- Used during animal cell division (not present in
plant most other cells)
31Prokaryotic Cells
- Ribosomes
- DNA or RNA
- cytoplasm
32Cell Boundaries
- Cell Membrane
- 1. Controls what goes in out
- 2. Support protection
- Cell Wall
- 1. Support protection
33Diffusion 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.)
34Concentration 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. Concentration10g/L
35Diffusion
- 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)
36Equilibrium
- When solute concentration is equal throughout the
solution
37Osmosis
- The diffusion of water through a membrane
- Some molecules are too large to move through a
membrane
38How Osmosis Workssee 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)
39Concentration 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)
40How Osmosis Works in Cellssee p 186 of text, Fig
7-16
- Isotonic Cell maintains its shape