Download Cell structure and function

Cell structure and function
*Show 2 video clips Honors book.
Chapters 7.1- 7.2
biology chap7.1-7.2 last updated
9/10/2010
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Voc Terms 7.1-7.2
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Cell
Cell theory
Cell membrane
Nucleus
Eukaryote
Prokaryote
Cytoplasm
Organelle
Vacuole
Lysosome
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Cytoskeleton
Centriole
Ribosome
Endoplasmic reticulum (smooth and
Rough)
Golgi apparatus
Chloroplast
Mitochondrion
Cell wall
Lipid bilayer
Selectively permeable
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What to know:
• Name the scientist who first observed
living and non living cells.
• State the three principles of the cell theory.
• Explain why the cell is considered to be
the basic unit of life.
• Know all cell organelles and functions
• Why are cells so small
• Explain a fluid mosaic model
• Know diff/sim between plant and animal
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Discovery of cells
• Cell- is the smallest unit that can carry on
all of the processes of life.
• 1665, English scientist Robert Hooke
used a light microscope to look at cork
• Leeuwenhoek- Dutch trader (1632-1723)first person to look at living cells (protists)
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Discovery of cells
150 years after Leeuwenhoek
1838- Matthias Schleiden – plants were
composed of cells
Theodore Schwann- animal were also made
of cells
Rudolf Virchow (1821-1902) said all cells
come from other cells
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Developments in Cell Biology
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1665- Hooke discovers cork cells
1827- Baer discovers mammalian egg
1855- Virchow adds to cell theory
1857- Golgi discovers the Golgi apparatus
in the cell
• 1996- Scotland researchers clone a sheep
from an adult sheep cell
• 2004- Tissue engineering used to grow
new skin an bone for transplant.
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Cell Theory
3 parts:
1. All living organisms are composed of one
or more cells.
2. Cells are the basic units of structure and
function in an organism.
3. Cells come only from the reproduction of
existing cells.
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The Cellular Basis of Life
All living things share several basic characteristics:
1. Organized parts- Made of cells
2. Obtain energy from their surroundings/
Perform chemical reactions (metabolism)
3. Change with time (Evolution)
4. Respond to their environments (Stimuli)
5. Reproduce (asexual and sexual)
6. Made of DNA
7. Regulate internal conditions (Homeostasis)
8. Grow and develop
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Cell Diversity
• Cells function influences
its physical features!!
Cell shape:
- Cells shape can be simple or complex
depending on the function of the cell
- Each cell has a shape that has evolved to
allow the cell to perform its function
effectively
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Cell Diversity
Cell size:
- Size of the cell is limited by the
relationship of the cell’s outer surface area
to its volume
- As the cell grows its volume increases
- Smaller the cell the more efficient it is in
allowing nutrients and oxygen to pass in
and out of the cells
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Basic Parts of the Cell
4 common features in all cells
1. Plasma membrane: or cell membrane, covers a cell’s
surface and acts as a barrier between the inside and
outside of a cell (in and out)
2. Cytoplasm: fluid, cytoskeleton, and organelles except
cytoplasm
- cytosol: cytoplasm that has no membrane bound
organelles (20% protein)
3. Coded information in the form of DNA
-some float freely inside the cell or
-Nucleus: membrane bound organelle that contains a
cell’s DNA
4. Ribosomes- makes proteins
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2 Basic types of cells
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Prokaryotesa. lack a membrane bound nucleus and membrane
bound organelles
b. have DNA is concentrated in the Nucleoid
c. have two domains: Archaea and Bacteria
2. Eukaryotesa. Organisms made up of one or more cells that have
a nucleus and membrane-bound organelles
b. have a variety of sub cellular structures called
organelles
c. tend to be much larger than
prokaryotes
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Cellular Organization
Cells are specialized and unable to survive
independently
Cells Tissues organs Organ system
Muscle cells muscle tissues Heart
circulatory system
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Cell organelles and features
Plasma membrane:
- it allows for only certain molecules to
enter or leave the cell
- it separates internal metabolic reactions
from the external environment
-excretes waste
- interaction with environment
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Membrane Lipids
Made of phospholipids
They have both a polar (hydrophilic) phosphate
head and two non polar (hydrophobic) fatty acid
tails
Double layer is called phospholipid bilayer
Eukaryotes also have lipids called sterols located
between the tails of the phospholipids (most
common is cholesterol, prevent the membrane
from freezing at low temps)
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Membrane Proteins
1. Integral proteins- specific proteins that are
located in the lipid bilayer
2. Peripheral proteins- located on the outside of
the membrane not embedded in it
Fluid mosaic model
- phospholipid bilayer behaves like a fluid more
than it behaves like a solid
- Proteins can mover laterally within the bilayer
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Nucleus
• Houses and protects genetic information
• Chromatin- DNA, long thin fibers
• Chromosomes- condensed DNA
Nuclear Envelope- double membrane that
surrounds the nucleus
Nuclear pores- protein-lined holes, passageways
for RNA and other materials to enter or exit the
nucleus
Nucleolus- dense area, where DNA is
concentrated and it is making ribosomal RNA
Ribosomes- organelles made of protein and
protein synthesis in the cytoplasm
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Mitochondria
• Tiny organelles that transfer energy from organic
molecules to ATP
• Powers most of the cell’s chemical reactions
• Highly active cells-muscles cells have hundreds of them
• Fat storing cells have few
• Inner and outer phospholipid membrane
• Inner membrane has many folds- cristae, which contain
proteins that carry out energy harvesting chemical
reactions
• Contain own DNA
• Can reproduce only by the division of
preexisting mitochondria
• Originated from prokaryotic cellssymbiotic relationship
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Ribosome
• Small, roughly spherical organelles that
are responsible for protein synthesis
• Do not have a membrane
• Made of protein and RNA molecules
• Developed in the nucleolus and completed
in the cytoplasm
• Some float freely in cytosol other in R-ER
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Endoplasmic Reticulum
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System of membranous tubes and sacs
(cisternae)
• Intracellular highway- particles move
from one part to another
• Amount depends on the cells activity
Two types
1. Rough
2. Smooth
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Rough Endoplasmic
Reticulum
• Interconnected, flattened sacs covered
with ribosomes
• Produces phospholipids and proteins
• Proteins are exported from the celldigestive enzymes
• Abundant in cells that produce large
amounts of protein for export , digestive
glands, antibody-producing cells
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Smooth ER
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Has no ribosomes
Most cells have few S-ER
Builds lipids- cholesterol
Ovaries/testes- produce steroid hormone
estrogen and testosterone
• Skeletal and heart muscles- release
calcium stimulates contraction
• Abundant in liver and kidney- detoxify
drugs/poisons
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Golgi Apparatus
• System, flattened membranous sacs
• Packaging system- UPS
1. receive vesicles from ER with new
proteins or lipids
2. travel in the Golgi- modify them
3. redirected to various parts of the cell
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Vesicles
Can be small, spherically shaped sacs that
are surrounded by a single membrane
1. Lysosomes- vesicles that bud from the
Golgi and contain digestive enzymes
2. Peroxisomes- abundant in liver and
kidney (H2O2)
3. Other-glyoxysomes, endosome,
contractile vacuoles
4. Protein synthesis
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Vesicles cont:
4. Protein synthesis
a. proteins are assembled by ribosomes on the
rough ER
b. Vesicles transport proteins to the golgi
apparatus
c. the golgi modifies protein and packages
them in new vesicles
d. vesicles release protein that have
destinations outside the cell
e. vesicles containing enzymes remain inside
the cell as lysosomes, peroxisomes,
endosomes
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Cytoskeleton
Network of thin tubes and filaments that
crisscrosses the cytosol, give it shape
1. Microtubules- hollow tubes made of protein
called tubulin, anchor, shape
2. Microfilaments- long threads of the beadlike
protein actin, double strands
3. Intermediate filaments- rods that anchor the
nucleus, shape of nucleus
4. Cilia and flagella- hair like structures that
extend from the surface of the cell
5. Centrioles- occur in animal cells , organize for
cell division
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Plant cells p 87
Plants have 3 structures that are extremely
important to plant function:
1. cell walls
2. large central vacuoles
3.chloroplast
Plants are different than animals- plant make their
own carbon-containing molecules from the
carbon in the environment (photosynthesis)
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Parts:
1. Cell wall- rigid layer that lies outside the
plasma membrane, made of carbohydrates
called cellulose
2. Central vacuole- stores water, metabolic
wastes, other materials, 90% of cell, if the cell
shrinks the plant wilts
3. Chloroplast- organelles that have own DNA,
have a double membrane
a. chloroplast- light energy to make carbs,
(thylakoids, chlorophyll)
b. chromoplast- colorful pigments
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Prokaryotes vs Eukaryotes
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Plant vs Animal
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What do all cells have?
Common features:
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Animations
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http://www.cellsalive.com/cells/cell_model.htm
http://www.scsc.k12.in.us/SMS/Teachers/Martin/intro.htm#Resources
http://www.biology4kids.com/files/cell_main.html
http://www.ibiblio.org/virtualcell/tour/cell/cell.htm
http://projects.edtech.sandi.net/miramesa/Organelles/animal.html
http://library.thinkquest.org/12413/structures.html#centrioles
http://learn.genetics.utah.edu/content/begin/cells/insideacell/
http://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookCELL2.html
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