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Cells
Cell Theory, Prokaryotes, and
Eukaryotes
Cell Theory
1.
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Living organisms are composed of cells.
Cells are the smallest unit of life.
Cells come from pre-existing cells.
Relative size of cell
Types of cells
Prokaryotic Cells
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Prokaryotes do not have a nucleus
The DNA exists as a single circular
chromosome
Your Turn
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What type of organisms are prokaryotic?
Can you remember what the other major
type of cell is called?
Eukaryotic cells
complex cells with organelles
Eukaryotes – Cell Parts
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Plasma membrane
Nucleus
Ribosomes
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Endoplasmic Reticulum
Golgi Apparatus
Lysosomes
Mitochondria
Centrioles
Plasma Membrane
Function: separates internal cell environment
(cytoplasm) from exterior environment
 Structure:
 Phospholipid bi-layer that surrounds cell
 Contains various types of membrane proteins
 Selectively Permeable: allows specific
substances to cross membranes but not
others
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Plasma Membrane Fluid Mosaic
Model
Nucleus
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Location of genetic material (DNA
chromosomes)
Functions to separate DNA from the rest of
the cell
Nuclear Envelope
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Nuclear pores allow entry
and exit of molecules
mRNA between nucleus
and cytoplasm
Ribosomes
Make proteins
 Composed of two
subunits
 Located in cytoplasm
or RER
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Endoplasmic Reticulum
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Two Types
Rough ER (RER) and smooth
Rough
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studded with ribosomes on outer surface  site of
protein synthesis
Golgi Apparatus
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Receives vesicles
from ER
Modifies, sorts and
packages
macromolecules
Sends
macromolecules to
final destination (via
vessicles)
Your Turn
Make a simple
diagram of a
cell and
highlight the
pathway by
which proteins
are made.
Protein Trafficking
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Proteins destined for specific cellular
locations such as the plasma membrane or
lysosomes are synthesized at the RER
Vesicles transport proteins to Golgi
apparatus
From Golgi apparatus proteins are sent, via
vesicles, to specified cellular location
Mitochondria
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It is the cell’s source
of energy: it makes
energy from glucose
(cellular respiration) (
Parts include:
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Double membrane
DNA
Lysosomes
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Small organelles filled
with enzymes
Used to breakdown
macromolecules or
damaged organelles

WE STOP HERE FOR TODAY!
Plant Cells
Plant cells are eukaryotes with additional
modifications
 Chloroplasts
 Cell walls
 Central vacuoles
 No centrioles
Chloroplasts
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Location of photosynthesis
Photosynthesis: the
transfer of light energy into
the chemical bonds of
glucose
Parts include:
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Double Membrane
DNA
Cell wall
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maintains cell shape
prevents excessive water
uptake
holds the whole plant up
against the force of gravity
Composed of the
polysaccharide cellulose
Central Vacuole
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Used for storage
of starch
Filled with water,
functions in
maintaining cell
pressure
Eukaryotes
State Three differences between plant and
animal cells.
Eukaryotes
State Three differences between plant and
animal cells.
1. Plants have chloroplasts, animals don’t
2. Plants have cell walls, animals don’t
3. Plants have large central vacuole,
animals don’t
Animal and Plant Cell Comparison