Download basic parts of a cell - Marissa Junior/Senior High School

Chapter 4
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Cell: the smallest unit that can carry on all of
the processes of life.
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Studied nature
Used “light microscope” pg 69
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Viewed a thin slice of cork
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Saw many little boxes
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CELLS
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First to observe living cells
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Microscope lens was 10x that of Hooke
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Was first able to see unseen world of
microorganisms
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First to view a REAL cell
Botanist
First to view plant cells
Concluded: All plants are composed of cells.
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Zoologist
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Concluded: All animals were made of cells.
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Physician
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All cells come from other cells.
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1. All living organisms are composed of one
or more cells.
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2. Cells are the basic units of structure and
function in an organism.
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3. Cells come only from the reproduction of
existing cells.
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Discovery of cells and cell theory:
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 MICROSCOPE
1. made of organized parts
2. obtain energy from their surroundings
 3. perform chemical reactions
 4. change with time
 5. respond to the environment
 6. reproduce
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In a body: pg 72
 Different cells
 Different shapes
 Different functions
 All in same body
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Shape reflects the different functions
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PAGE 72
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A few types of cells are large enough to be
seen without a microscope
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Ex. Giraffe’s nerve cells: 6 ½ ft long
 Human egg cell: size of a period
MOST cells: 1/500th the size of a period
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SURFACE AREA-TO-VOLUME RATIO
Nutrients and oxygen go in
 Waste goes out
BOTH pass through surface
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Happens QUICKLY therefore need more
surface area to volume page 73
Cells MUST be microscopic!!!
3 basic parts to all cells
1. Cell Membrane
2.
3.
Cytoplasm
Nucleus
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Also called the plasma membrane
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Covers the surface
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Acts as a barrier
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All materials enter or exit through this
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Hold all of the organelles
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Control center
Holds DNA
Membrane bound and free floating DNA
PROKARYOTES
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Lack a membrane-bound
nucleus
Lack membrane-bound
organelles
May have a nucleoid:
concentrated area of DNA
DOMAIN Archaea
DOMAIN Bacteria
EUKARYOTES
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In organisms made up of
one or more cells
Contain organelles
Larger in size than
prokaryotes
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Page 76
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Cell
Tissue
Organ
Organ System
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Functions:
 A. Allows only certain molecules to enter or leave
the cell
 B. Separates reactions inside the cell from outside
the cell
 C. Excretes waste
 D. Interacts with environment
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Phospholipids
Proteins
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Cell surface markers – emerge from only one
side of the membrane

Receptor proteins – recognizes and binds to
substances outside the cell

Transfer proteins – helps substances move
across the membrane
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Enzyme –
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Houses and protects genetic information
 Chromosomes: holds DNA
 Nuclear Envelope: surrounds nucleus
Nucleolus: denser area in nucleus
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Holds organelles
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Mitochondria
Ribosomes
Endoplasmic reticulum
Golgi aparatus
Vesicles
Microtubules
Microfilaments
centrioles
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Mitochondria: tiny organelles that transfer
energy into ATP

ATP: Adenosine triphosphate
 Powers the cell’s chemical reactions
 HIGH in # in muscle cells!
 FEW in # in fat cells.
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Small, roughly spherical organelles
Responsible for building protein
No membrane
Made of protein and RNA
Created in nucleus, finished in cytoplasm
Found in
 Cytoplasm
 Some endoplasmic reticulum
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Called ER
System of tubes and sacs (cisternae)
Function as a “highway”: a path along which
molecules move from one part of the cell to
another
2 types:
 Rough
 Smooth
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System of interconnected, flattened sacs
covered with RIBOSOMES
Pg 81
Produces phospholipids and proteins
Ribosomes on ER:
 Produce digestive enzymes that contain proteins
 Vesicles (sacs) pinch off and store these enzymes
until they are released
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Smooth appearance
Builds
In ovaries and testes: produces hormones
*abundant in liver and kidneys:
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Long term alcohol and drug abuse:
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Pg 82
Another system of flattened, membrane sacs
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Sacs closest to the nucleus receive vesicles
from the ER containing newly made proteins
or lipids
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Proteins get “address labels”
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VESICLE: small sacs that head to the plasma
membrane and release contents outside of
cell
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1. LYSOSOME
2. PEROXISOME
3. others
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Vesicles from Golgi Apparatus that contain
digestive enzymes
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Breakdown proteins, carbs, fats, bacteria.
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Responsible for breaking down cell when it is
time to die!
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Abundant in liver and kidney
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Detoxify alcohol and other drugs
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Also breakdown fatty acids
1. proteins assembled by ribosomes on
rough ER
2. Vesicles transport proteins to the
golgi apparatus
3. Golgi modifies the proteins and packages
them in new vesicles
4. Vesicles release proteins that have
destination outside of cell
5. Vesicles needing to remain inside of cell stay.
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Network of thin tubes and filaments
Give shape to the cell from the inside
ex. Tent poles
Also acts as a system of internal tracks to allow
items to move around in cell
Microtubules, Microfilaments, &
Intermediate filaments
Hollow tubes made of protein called
“tubulin”
1. Hold organelles in place
2. Maintain cell’s shape
3. Act as track to guide organelles
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Finer than microtubules
2 strands of intertwined protein
1. contribute to cell movement
2. muscle contraction
3. maintainance and changing of shape
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Rods that anchor the nucleus and other
organelles to their place
Maintain INTERNAL shape of nucleus
CILIA
 Extend from surface of cell
 Short
 Large #’s
 Inner ear: vibrate and help
detect sounds
 Protisits: sweep food into
mouthlike opening
FLAGELLA
Extend from surface of cell
Long
less #’s
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Plant cells have 3 additional kinds of
structures
1. cell wall
2. large central vacuole
3. plastids
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Make their own food: photosynthesis
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Must reach up towards the sun
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Need to hold water
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Rigid layer outside of
plasma membrane
Made of cellulose: a carb
that makes the cell
like a stiff box
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2 layers:
 Primary wall
 Secondary wall (wood)
Large, fluid-filled
organelle
 Mainly stores water
 90% of the plants
volume
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Causes plant to stand
upright
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Used in photosynthesis
Use light energy
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Contain chlorophyll:
green pigment that
absorbs light and
captures the light
energy
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Colored pigment
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Found in
carrots: orange
flowers: red, purple,
yellow & white