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LECTURE 3. CELL ORGANELLES
Sapakhova Zagipa Beisenovna, PhD
-nucleus
-cytoplasm
-nucleolus
-cytoskeleton
-cell membrane
-vacuole
-mitochondria
-chloroplast
-golgi Apparatus
-centrioles
-lysosomes
-ribosomes
-endoplasmic reticulum(ER)
*Rough ER & Smooth ER
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Nucleus
The “brain” of the cell
Controls all of the
cellular activities
DNA is inside the nucleus
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Nucleus
CHROMOSOMES- are found inside
the nucleus
carry the information that
Chromosomes – determines what traits a
living thing will have
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DNA - Deoxyribonucleic acid
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DNA - Deoxyribonucleic acid
DNA carries the genetic information of a
cell
Consists of thousands of genes
It specifies everything that is needed for
the maintenance, function, and replication of
the cell
It is made up of 4 different bases:
(A) adenine
(C) cytosine
(T) thymine
(G) guanine
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DNA - Deoxyribonucleic acid
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NUCLEOLUS
The dark area in
the nucleus
Like a tiny
nucleus inside the
nucleus.
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CELL MEMBRANE
 holds the cell together
 keeps all of the pieces (like the organelles
and the cytoplasm) inside the cell
 controls what goes in and out of the cell
Example: like a big plastic bag with tiny
holes in it
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How does the cell membrane work?
Has 2 layers of MOLECULES = BILAYER
Bi means two
The layers are made up of molecules called
phospholipids
**THINK OF a sandwich with two pieces of
bread and some stuffing on the inside
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Cell Membrane: PHOSPHOLIPIDS
Each phospholipids
has a HYDROPHOBIC
and HYDROPHILIC
end
•HYDRO = means water
•PHOBIC = means afraid
•PHILIC = means loving
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Cell Membrane: PHOSPHOLIPIDS
 One end of the molecule is “afraid” of
the water and one end “loves” being in the
water.
 Proteins are stuck inside the membrane
 Proteins are across the bilayer and
make the holes that let ions and molecules
in and out of the cell
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Mitochondria
 Mito = Mighty / Power
 The Power-House of the cell
 They break down food molecules so the
cell has the energy to live
 If a cell needs a lot of energy…it will have
more mitochondria
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The Mitochondria structure has three main
parts:
OUTER MEMBRANE:
covers the
mitochondria
INNER MEMBRANE:
folds many times to
increase the surface
area because
chemical reactions (glycolysis) occur here
So…the more space it has the more energy it
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can create
MATRIX: a fluid
that has water
and proteins all
mixed together
(like a solution)
•The proteins
take the food
molecules in and
combine them
with Oxygen to
release the
energy
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Endoplasmic Reticulum
 also known as the “ER”
 it is an organelle inside the cell that is
made up of membranes that are in the
CYTOPLASM of the cell
There are two different
Smooth ER
Rough ER
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Smooth ER
 Main function is to collect, maintain &
transport things
 Shaped slightly tubular
 Creates steroids
 Stores Ions for the cell to keep nutrients
balanced
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Rough ER
It has bumps all over it giving it a “rough”
appearance
Bumps are called RIBOSOMES
ER collects the proteins (built by the
ribosomes) and creates a bubble around them
 VESICLE- is formed when the ER pinches
off a part of its membrane
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MOVEMENT of VESICLES
**The vesicle can then move to the Golgi
apparatus or the cell membrane
1)
If the vesicle floats to the cell
membrane, the proteins are going to be sent
out of the cell……or (exocytosis)
2) If they move to the Golgi Apparatus, the
proteins will be used inside the cell
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EXOCYTOSIS- The release of intracellular
molecules (hormones or proteins)
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Osmosisthe movement of
water across the
cell membrane
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GOLGI APPARATUS
•Also called the Golgi Complex
•It is made up of a stack of flattened out sacs
…like a loose stack of pancakes
WHAT DOES IT DO?
1) it takes simple molecules and combines them to
make larger molecules.
2) takes those larger molecules and puts them
into packs called GOLGI VESICLES
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Think about building a model of a ship (that's the
molecule). Then take that model and put it in a
bottle (that's the vesicle).
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Golgi apparatus
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LYSOSOMES (primarily animal)
•They combine with the food taken in by the cell
•The enzymes in the lysosome bond to food &
digest it (acidic interior)
• Next…smaller molecules are released which
are absorbed by the mitochondria
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LYSOSOMES
• When an organelle no longer works, the
lysosome will attach itself to it and break it
down like food (kind of like a cannibal)
– Chemicals can then be reabsorbed or
excreted
• Lysosomes can also destroy the cell if it
breaks open accidentally
– “Suicide Sacs”
– UV light damages lysosome membrane
• The enzymes inside the lysosome spread
throughout the cell and digest it
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LYSOSOMES
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Lysosome Animation
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CYTOPLASM
Protoplasm- everything inside the cell membrane
Cytoplasm- everything inside the cell membrane &
outside of the nucleus except the cell’s nucleus
Cytosol:
– Mostly H2O
– Contains organelles
– Contains salts, dissolved gasses & nutrients
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CYTOPLASM
cytoplasm
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CYTOSKELETON
• Chief functions include:
– movement of material through the cell
for stuff not diffusion or osmosis
– maintaining the shape of the cell
– keeping the cell from getting
smashed
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VACUOLE
• Vacuoles are “bubbles” that float in the
cell
• Vacuoles are more important to the
survival of plant cells than they are to
animal cells
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VACUOLE: STORAGE IN PLANT CELLS
• Vacuoles in plants support structure
• Vacuoles hold onto things that the cell might
need…like a backpack
• There are some vacuoles that hold onto waste
products, similar to having a big septic tank
• Storing waste products protects the cell from
contamination
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VACUOLE CONT’D
So, when there is no water…the vacuole
shrinks and the cell wall is the only
thing holding the plant together.
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You will know that a plant's vacuoles are
shrinking when you see the plant begin to
droop over
HOLDING UP THE WALLS
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Turgor Pressure- force exerted by the water
entering (osmosis) the vacuole, which then
swells exerting internal force on the cell wall
•Causes “rigidity” so the plant my increase
by stacking cells
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Chloroplast
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Chloroplast
•the site of photosynthesis in eukaryotic
cells
•disk-like structures
•composed of a single membrane
•surrounding a fluid containing stacks of
membranous disks
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•SOLAR energy
radiated from the
sun is captured by
plants(chloroplast)
Chloroplast
•Then it is
instantaneously
changed into
ELECTRICAL
energy
•Then packaged as
CHEMICAL energy
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Chloroplast
•photosynthesis takes place inside the chloroplast
the process in which plant use
Photosynthesis- water, carbon dioxide, and energy
form the sun to make food
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Chloroplast
•No energy transformation is 100%
efficient
•Not all the solar energy captured is
converted to electrical and then chemical
energy.
•Some of it gets lost as heat or other
forms of energy (light)
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Centrioles:
•generally appear in animal cells
•they look like two cylinders at right angles to
one another
•when viewed with an electron microscope, the
cylinders show up as nine bundles of tiny
microtubules arranged in a circle
•they help to form the fibers that move
chromosomes around when the cell is dividing
•as animal cells prepare for cell division these
two centrioles separate and go to opposite
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ends of the cell.
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Ribosomes
•small dot-like structures in cells
•they are often associated with forming
rough ER
•Ribosomes are the site of protein synthesis
in cells
•they are made in the nucleus of the cell
•A ribosome can make the average protein in
about one minute
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Ribosome Structure
•Ribosomes are made up of proteins and
ribonucleic acid(RNA)
•These molecules are arranged into two
subunits
•These subunits are attached to each other
and together form the entire ribosome
•When viewed through a light microscope the
ribosomes appear as dots
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Types of Ribosomes
•There are two kinds of ribosomes
1) Attached to the rough ER
2) floating in the cell cytoplasm
•Attached ribosomes make proteins that are
used in the ER or transported within the ER
•Free ribosomes make proteins that are used
in the cytoplasm
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Assignment Part A
(slides 1-11)
Directions: Write-out and highlight the following
questions. Then use your notes to answer them.
1. Which organelle is known as the “Brain” of the cell?
2. If you look at a picture of a cell, how would you
recognize the nucleolus?
3. List the 3 main jobs of the cell membrane
4. Explain why the cell membrane has tiny holes made
of protein in it.
5. The term hydro means _________.
A. If something is hydrophobic it is _________
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B. If something is hydrophilic it is __________
Assignment Part B
(slides 11-23)
Directions: Write-out and highlight the following
questions. Then use your notes to answer them.
1. Which organelle is known as the Power House” of
the cell?
2. The mitochondria of a cell share the same job as
the __________ (hint- an organ) in the human body.
3. Explain how you could distinguish the rough ER
from the smooth ER.
4. What is the main job of the smooth ER?
5. What type of reactions occur on the inner
membrane of the mitochondria? (produces energy)
6. The process of H2O moving across the cell
membrane is called?
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Assignment Part C
(slides 23-)
Directions: Write-out and highlight the following
questions. Then use your notes to answer them.
1. What is the main function of a lysosome?
2. What happens if a lysosome breaks open?
3. Explain the difference between cytoplasm and
protoplasm. (draw a diagram if it will help you)
4. Why are vacuoles important to PLANTS?
5. Which organelle is the site of photosynthesis?
6. What are the three main ingredients for
photosynthesis?
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Assignment Part D
(slides 23-)
Directions: Write-out and highlight the following
questions. Then use your notes to answer them.
1. Centrioles are usually found in __________ cells.
2. What is the main function of a centriole?
3. List the two places you can find a ribosome in an
animal cell.
4. What do ribosomes make?
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See also wksht to go
with questions parts
B-D
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