CHAPTER 7 CELL STRUCTURE & FUNCTION PGS. 168 - 199 CELL STRUCTURE & FUNCTION.
Unit 4: Cell Structure & Function 1.
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Transcript of Unit 4: Cell Structure & Function 1.
Unit 4: Cell Structure & Function
http://koning.ecsu.ctstateu.edu/cell/cell.html 1
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!
2
Discovery of Cells, cont.
• Matthias Schleiden (1838) concluded plants made of cells
• Thoedor Schwann (1839) concluded all animals made of cells
3
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 p_____________ cells through cell division.
4
Definition of Cell
A cell is the smallest unit that is capable of
performing life functions.
5
Examples of Cells
Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria
6
Two Types of Cells•Prokaryotic
“pro-” means “before” (like “pre”)“karyon” means “nut” or kernel”No n______________Older life forms are prokaryotes
•Eukaryotic“eu-” means “true” + “karyon”= kernelHas nucleus“newer” life forms are prokaryotic 7
Prokaryotic Cells
• Do not have o___________ surrounded by membranes
• V. few internal structures
• All prokaryotes are– one-celled
organisms– B___________
http://library.thinkquest.org/C004535/prokaryotic_cells.html8
Eukaryotic Cells• Contain organelles surrounded by membranes• Most living organisms are eukaryotic
– Plants, animals, f_____, algae
Plant Animal
http://library.thinkquest.org/C004535/eukaryotic_cells.html 9
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif 10
http://waynesword.palomar.edu/images/plant3.gif
“Typical” Plant Cell
11
Eukaryotic Cell Parts“Organelles”
12
Surrounding the Cell
13
Cell Membrane
• Outer membrane of cell that controls m______
in and out of the cell
• Double layers of fat “phospholipid bilayer”
http://library.thinkquest.org/12413/structures.html
What part of this word tells you that the cell membrane is made of fats?
14
Cell Wall
• Most commonly found in– plant cells – bacteria – fungi
• S_____ & p_____ cells
• Made of carbohydrate
http://library.thinkquest.org/12413/structures.html 15
Inside the Cell
16
Nucleus
• Directs cell activities
• Separated from c_______ by nuclear membrane
• Contains genetic material - DNA
17
Nuclear Membrane
• Surrounds nucleus
• Made of t____ layers
• Openings allow material to enter and leave nucleus
http://library.thinkquest.org/12413/structures.html18
Chromatin
• Form DNA takes most of the time.
• Like spaghetti
• Made of DNA wrapped up w/p_______.
19
Chromosomes
• In nucleus
• DNA wrapped up tight by proteins called “histones”
• Contain instructions for traits & characteristics
http://library.thinkquest.org/12413/structures.html 20
Nucleolus
• Inside nucleus
• Contains RNA to build proteins
http://library.thinkquest.org/12413/structures.html 21
Cytoplasm
• Gel-like mixture
• Surrounded by cell membrane
• Contains hereditary material in prokaryotes
22
Ribosomes
• Each cell contains thousands
• Make proteins
• Found on e___________ r________ & floating in the cytoplasm
http://library.thinkquest.org/12413/structures.html 23
Endoplasmic Reticulum• Moves materials around in cell
• Smooth type: – lacks ribosomes– Located in organisms that
produce _____ like _____
• Rough type (pictured):– R_____ are embedded in
surface – Located in organs responsible
for producing proteins, like the ________
http://library.thinkquest.org/12413/structures.html24
Mitochondria• Produces energy through
chemical reactions by breaking down f___ & c_________.– Also known as the
“powerhouse of the cell”
• Controls level of water and other materials in cell
• Recycles and decomposes proteins, fats, and carbohydrates
http://library.thinkquest.org/12413/structures.html 25
Golgi Bodies• Protein
'packaging plant'
• Move materials within the cell
• Move materials out of the cell
http://library.thinkquest.org/12413/structures.html26
Lysosome• Digestive ‘factory' for
proteins, fats, and carbohydrates
• Transports undigested material to c___ m_______ for removal
• The cell will break down if lysosome breaks!
http://library.thinkquest.org/12413/structures.html27
Vacuoles
• Membrane-bound sacs for storage, digestion, and waste removal
• Contains water solution
• Help plants maintain s______
http://library.thinkquest.org/12413/structures.html 28
Chloroplast
• Usually found in plant cells (not in animal)
• Contains green chlorophyll
• Where p__________ takes place
http://library.thinkquest.org/12413/structures.html 29
Centrioles
• Used during animal cell division (not present in plant & most other cells)
30
Flagellum
31
• Is a whiplike structure that extends outside the cell.
• Is used for movement.
Cilia
• Small, hairlike projections that extend outside the cell
• For m_______ & capturing food
32
Prokaryotic Cells
• Ribosomes
• DNA or RNA
• cytoplasm
33
Cell Boundaries
• Cell Membrane1. Controls what
goes in & out
2. Support & protection
• Cell Wall1. Support &
protection
34
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.)
35
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
This solution has a higher salt concentration
36
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)
37
Isotonic
• When solute concentration is equal throughout the solution
38
OsmosisVideo
• The diffusion of water through a membrane
• Some molecules are too large to move through a membrane
39
How 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)
40
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)
41
How Osmosis Works in Cellssee p 186 of text, Fig 7-16
• Isotonic: Cell maintains its shape
• Hypertonic
• Hypotonic
42