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Cell Structure
Review
Prokaryotic Cells
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Do not have a nucleus
Found in bacteria
Eukaryotic Cells
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Have a nucleus
Found in multi-cellular organisms
& some unicellular organisms
Cell Membrane
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Thin, flexible layer
Separates the cell from its surrounding
environment
Controls movement of materials into and out of
the cell
Helps maintain the cell’s internal environment
Nucleus
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Control center of the cell
Manages all of the cell’s
activities
Largest organelle
Contains the genetic
material (chromatin) the
cell needs to reproduce
and function.
Is surrounded by the
nuclear envelope and also
contains the nucleolus
and chromatin.
Nucleolus

The nucleolus is
located in the nucleus.

It manufactures the
subunits that combine
to form ribosomes, the
cell's proteinproducing factories.
Chromatin
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Coils of DNA and
protein that form
chromosomes.
Can be thought of as
chromosomes without
shape.
Granular-like
material found in the
nucleus containing
genetic information
Chromosome

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Worm-like / rodlike structures
formed from
chromatin during
cell reproduction.
They become
distinct during the
reproductive part
of the cell cycle as
the cell divides.
Composed of DNA
DNA
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The genetic material found in all living cells.
Contains the information needed for an
organism to grow, maintain itself, and
reproduce
Stands for deoxyribonucleic acid
Nuclear Envelope
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Has a double-layered
membrane that
separates the nucleus
from the cytoplasm.
Contains pores to help
facilitate the
exchange of materials
between the nucleus
and the cytoplasm
Cytoplasm
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Thick, jelly-like
substance
contained within
the cell membrane
Most of the work
of the cell is
carried out here.
The majority of
the organelles are
suspended in the
cytoplasm.
Endoplasmic Reticulum
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Network of channels/tubes leading from the
nuclear membrane into the cytoplasm
Helps transport materials between the
nucleus and the cytoplasm
Also involved in transporting proteins
Two types:
- Smooth E.R. = no ribosomes
-Rough E.R. = contains ribosomes
Ribosomes
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Sites of protein
manufacturing in the cell
Assemble proteins that:
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Create chemical messages
to run a cell.
Build cell organelles
Line the membrane of the
rough endoplasmic
reticulum & are found in
the cytoplasm
Protein

Your muscles, your organs, and your immune
system are made up mostly of protein

whether you're running or just hanging out,
protein is doing important work like moving
your legs, moving your lungs, and protecting
you from disease.

Proteins are sometimes described as long
necklaces with differently shaped beads.

Each bead is a small amino acid. These amino
acids can join together to make thousands of
different proteins.

Scientists have found many different amino acids
in protein, but 22 of them are very important to
human health.
Golgi Bodies
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Serve as storage and packaging centers.
Look like stacks of flattened sacs
Proteins made by the ribosomes are packaged
into vesicles (small pockets)
These packages are used by the cell and
sometimes are released from it.
Lysosomes
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Sac-like structures that
contain enzymes
Where digestion of cell
nutrients & food
molecules take place
Breaks down cellular
waste or things that are
harmful to the cell
• Similar to the job of
white blood cells
Mitochondria
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Organelles that cause the release of energy by
using oxygen to break down sugars.
Usually round or tube shaped
Releases food molecules that supply energy to
the cell; it is known as the powerhouse of the
cell.
Usually more than
one in a cell