Transcript Eukaryotic Cell Structure

Eukaryotic Cell Structure
Cell Wall
Found in cells of plants, fungi, bacteria,
and some protists.
 Fairly rigid structure found outside the cell
membrane.
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Cell Wall
Provides additional support and protection.
 Cell walls in plants are very porous which
allows molecules to pass through (not
selective).
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Nucleus
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Contains strands of DNA called chromatin.
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When the cell divides, chromatin condenses
to form chromosomes.
Controls the activity of organelles by
controlling protein production.
 Contains an organelle called the nucleolus
which makes ribosomes.
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Ribosomes
Where proteins are made.
 Has no membrane.
 Formed of RNA and proteins.
 During protein synthesis, ribosomes and
RNA translated from DNA leave the
nucleus through the nuclear envelope and
enter the cytoplasm
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Nuclear Envelope
Separates the nucleus from the cytoplasm.
 Double membrane.
 Made up of two phospholipid bilayers
containing small nuclear pores for
substances to pass through.
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Cytoplasm
Clear, gelatinous fluid inside a cell.
 Suspends organelles such as ER, golgi
apparatus, vacuoles, lysosomes,
chloroplasts, plastids, mitochondria, and
centrioles.
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Endoplasmic Reticulum (ER)
Site of cellular chemical reactions.
 Arranged in a series of highly folded
membranes.
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These folds allow a large amount of ER to do
work in a small amount of space.
Rough ER vs Smooth ER
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Rough ER
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Areas of ER where ribosomes are attached to
the surface and carry out protein synthesis.
Smooth ER
Areas of the ER not studded with ribosomes.
 Involved in numerous biochemical activities,
including production and storage of lipids.
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Golgi Apparatus
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Flattened stack of tubular membranes that
modify proteins.
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After proteins are made by ribosomes, they
are transferred to the golgi apparatus.
Golgi Apparatus
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Sorts proteins into packages and then
packs them into membrane-bound
structures called vesicles to be sent to the
appropriate destination.
Vacuoles
Membrane bound compartments or sacs.
 Temporarily store materials such as food,
wastes, and enzymes.
 Not usually present in animal cells.
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When they are present in animal cells, they
are very small.
Lysosomes
Organelles that contain digestive
enzymes.
 Digest worn-out organelles, food particles,
and engulfed viruses and bacteria.
 Has a membrane which prevents the
digestive enzymes from destroying the
cell.
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Lysosomes
Can fuse with vacuoles and dispense
enzymes into the vacuole, digesting its
contents.
 Sometimes lysosomes digest the cells that
contain them as in the case of a tadpole
tail.
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Chloroplasts
Located in the cells of green plants and
some protists.
 Capture light energy and convert it into
chemical energy.
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Store the chemical energy in bonds of sugar
molecules.
Belong to a group of plant organelles
called plastids.
Chloroplasts
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Has a double membrane.
Inner membranes are called thylakoid
membranes and are arranged in stacks of
membranous sacs called grana which trap
sunlight.
 Fluid that surrounds the stacks of grana is
called stroma.
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Plastids
Store materials such as starches, lipids,
and pigments.
 Named according to their color or the
pigment they contain.
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Chloroplasts contain the green pigment
chlorophyll which traps light energy.
Mitochondria
Membrane bound organelles in plant and
animal cells which transform energy for
the cell.
 Have an outer membrane and highly
folded inner membrane where energy
storing molecules are produced.
 Energy is then stored in bonds of other
molecules that cell organelles can access
easily and quickly when energy is needed.
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Cytoskeleton
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Network of tiny rods and filaments.
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Microtubules
 Thin
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hollow cylinders made of protein.
Microfilaments
 Smaller
solid protein fibers.
Cytoskeleton
Forms a framework or structure for the
cell.
 Can be dismantled in one place and
reassembled somewhere else in the cell,
changing the cell’s shape.
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Cytoskeleton
Anchors and supports many organelles.
 Provides a highway system through which
materials move within the cell.
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Centrioles
Found in cells of animals and most
protists.
 Occur in pairs.
 Made up of microtubules.
 Play an important role in cell division.
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Cilia and Flagella
Organelles made of microtubules.
 Aid in locomotion and/or feeding.
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Major means of locomotion in single celled
organisms.
Cilia and Flagella
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Cilia
Short, numerous projections that look like
hairs.
 Motion similar to oars in a rowboat.
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Cilia and Flagella
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Flagella
Long projections.
 Move with a whip-like motion.
 Cells usually only have one or two.
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