Structure of a Cell
. Cell Structure
Cell (plasma)
Membrane
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I,
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<Cell Wall
~Iant cells only)
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Nucleus
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¢ytoplasm
!
!
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yacuoles
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II
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,
fbosomes
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!
Description
Function
• Separate cell interior from
• A phospholipid bilayer
(double layer), with
the external environments;
embedded protein and
• controls what enters/leaves
carbohydrate molecules,
the cell;
that surrounds the cell.
• involved in cell
• Membrane molecules are
communication
free to float around.
• **Fluid Mosaic Model**
• Firm but porous structures Provides structural support for
the cell.
surrounding membrane.
• Made of cellulose
• "Control Center" ofthe
• Separated from the
cell, directions all of the
cytoplasm by a double
cells activities.
membrane called the
nuclear envelope.
• Contains the genetic
information (i.e. DNA)
• Spherical in shape.
• Contains a dense spherical
structure called the
nucleolus, which produces
ribosomes.
Contains various chemicals
• Interior of cell.
and molecules (e.g. ions,
• Consists of an aqueous
amino acids, enzymes, ATP,
solution called cytosol,
carbohydrates)
and the organelles
• Membrane-bound sacs.
• Much larger in plant cells
• Storage of starch
molecules, water and
wastes.
• In plants, the pressure in
the vacuoles keeps the cell
membrane pressed firmly
against the wall, therefore
provides structural support.
• Dense-looking, spherical
• Protein Synthesis.
granUles.
• Site where amino acids are
Free-f10ating
in
cytoplasm
assembled into proteins.
•
or attached to surface of
rough endoplasmic
reticulum.
Endoplasmic
Reticulum
<{olgi Apparatus
rima)
~ysosomes
• Series of membranous
tubes that connect to the
nuclear envelope.
• 2 types:
1) Rough E.R. - has
attached ribosomes.
2) Smooth E.R. does not
have attached ribosomes.
Flattened stack of
membranes
• Membrane-bound sacs
(vesicles).
ceUs only)
• Produced by golgi
apparatus and E.R.
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• Contains hydrolytic
enzymes, which digest
molecules.
~ .itochondrion
• Rod-shaped.
(I ~I:
• Smooth outer membrane
n itochondria)
with inner membrane
folded into cristae.
• Contains an inner liquid
solution know as the
matrix.
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qhloroplasts
• Double- membrane.
(Ilant cells only)
• Inner membranes are
arranged into a system of
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interconnected
I
compartments called
thylakoids, which are
stacked to form grana.
• Contain the green pigment
chlorophylL
• Filled with fluid called
stroma
!
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Rough E.R. - site of protein
synthesis
Smooth E.R. - manufactures
fats (Lipids)
• Receives and modifies fats
and proteins produced by
the E.R.
• Packages fats and proteins
into vesicles for transport
out ofthe cell.
• Breaks down molecules
• digests food particles
• destroys microorganisms,
• breaks down old/damaged
organelles,
• destroys old cells
("apaptosis")
• Site of cellular respiration,
which produces cellular
energy.
• Glucose molecules are
broken down to produce
molecules of ATP, the
units of cellular energy.
• Site ofphotosynthesis.
• Enables plants to convert
sunlight, CO 2 and H 20 into
carbohydrates from energy.