Eukaryotes
Cell (Plasma) Membrane
 Selectively permeable membrane- regulates what
H2O is polar
enters/leaves the cell
 Composed of 2 layers of specialized lipids (called
phospholipids), proteins, and carbohydrates
 Separates internal and external environments
Phospholipid
-
Phospholipid bilayer
Cell Wall
 Rigid structure OUTSIDE of the cell membrane in
plant cells.
 Provides shape and protection
 Plant cell walls – mostly cellulose

Which organic compound is cellulose?
 Prokaryotic cell walls- peptidoglycan
 Contain openings (plasmodesmata) that materials
(H2O and small molecules) can move through to
neighboring cells
 **NOT found in animal cells**
Vacuoles
 Central Vacuole- A Large, membrane-bound
compartment that stores ions, nutrients, and wastes.
 Contributes to plant growth when full
 Contractile Vacuole-some unicellular eukaryotes
(freshwater algae) use them to pump out excess water.
 Allows them to regulate concentration of salts & other
molecules.
 Food Vacuole- formed when cell membrane
surrounds food particles outside the cell and draws
them into the cell. Lysosomes fuse with food vacuoles
and digest the food particles.
 Some central vacuoles found in leaf cells contain
poisons that offer protection against plant-eating
animals.
 Others contain the pigments giving flowers color
which attracts pollinating insects.
Nucleus
 Control center, boss, or “brain” of the cell
 Contains the genetic material (DNA) in eukaryotic cells
 Surrounded by a thin double membrane called the
nuclear envelope.
 Nuclear Pores- small openings in the nuclear envelope
that allow substances made in the nucleus to move out into
the cytoplasm.
Nucleolus
 Site of ribosome part, or subunit, production.
 Q: How could ribosome parts enter the cytoplasm
from within the nucleus?
 Composed of DNA, RNA, and proteins.
 Disappears at start of cell division and reappears at
the end.
Ribosomes
 Synthesize (make) proteins – “ protein assembly lines”
 Small organelle composed of RNA and proteins
 Locations within cells:
1.
2.
3.
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Endoplasmic reticulum-RER (bound)
Nuclear membrane (bound)
Cytoplasm (free)
Free ribosomes- make proteins that remain inside the cell, such as
proteins that build new organelles or enzymes used to speed up
reactions.
Bound ribosomes- make proteins to be released from the cell
Note: Ribosomes can switch between free and bound states
depending on the type of protein that the cell needs.
Endoplasmic Reticulum (ER)
 Network of membranes that form a transportation
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route for materials
Synthesizes many molecules for transport
Connected to the outer membrane of the nuclear
envelope
Rough ER- studded with ribosomes
Smooth ER- NO ribosomes. Contains various
enzymes enabling the SER to carry out different
functions
 Ex: Lipid synthesis.
To the Golgi
Receive, Package, Deliver
“receiving dock”
for vesicles
animation
Enzymes refine
and modify
vesicles
Vesicles travel to
specific parts of
cell
Golgi Apparatus
 Receives products (Ex: proteins & lipids) from ER
contained in vesicles
 Arranged in pita bread-like stacks
 Modifies, stores, and routes them to their next
destination.
 Golgi enzymes chemically refine and modify ER
products.
Path of Proteins in Eukaryotes
 Ribosomes bound to the rough ER make proteins
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directly into the ER.
The rough ER membrane pinches off forming a vesicle
around the protein.
Vesicles carry the proteins through the cytoplasm to
the golgi apparatus where they fuse with the golgi.
Enzymes within the golgi modify the proteins as they
move through.
On the other side, the finished proteins (enclosed in
NEW vesicles) that bud from the golgi apparatus.
Vesicle membrane fuses with cell membrane- releasing
proteins outside the cell.
Path of Proteins in Eukaryotes
Endocytosis
Exocytosis
Mitochondria
 Site of cell respiration- Food energy used to make
ATP
 “Energy Factory” or “Powerhouse” of the cell
 Found in almost every eukaryotic cell
 Two membranes:
 Inner membrane – folding increases surface area for
ATP-producing enzymes to act on.
 Outer membrane
 Cell type determines number of mitochondria
Lysosomes
 Membrane-bound sacs containing digestive enzymes that
break down large molecules.
 Ex: nucleic acids, proteins, and polysaccharides
 Fuse with food vacuoles to digest contents and nourish
cell.
 “Cellular Safety Officers”- WBC lysosomes release
enzymes into vacuoles containing bacteria. Why?
 “Recycling Centers”- Engulfs and digests old, unused, or
damaged organelles. Molecules become available for
constructing new organelles.
Chloroplast
 Site of photosynthesis: Light energy used to make sugar
from CO2 and H2O.
 Light energy  Chemical (food) energy
 NOT FOUND IN ANIMAL CELLS
 Found in plants and algae
 Surrounded by a pair of membranes.
 Disks (within the inner membrane) are the chloroplast’s
solar “power packs”- allow them to trap solar energy
 Green color results from the pigment chlorophyll
Cytoskeleton
Cytoskeleton- web of protein fibers that provide support to the cell.
Fibers making up the cytoskeleton:
1. Microtubules: thick, hollow tube of protein subunits (parts)
that provide rigidity, shape, and organization to cells.
Made up of the protein tubulin.
• Provides “tracks” for organelles to move

•
Ex: Lysosome may reach a food vacuole using microtubules.
2.
Intermediate Filaments- moderately thick, anchor organelles
& enzymes to certain parts of cell.
3.
Microfilament: solid rod of protein, thinner than microtubules,
that enables a cell to move or change shape (Ex: amoeba)
1.
Made up of the protein actin.
Cell-Factory Analogy
Cell-Factory Analogy
Cell-City Analogy
 The Cell Song: http://youtu.be/rABKB5aS2Zg
 A Tour Of An Animal Cell:
http://youtu.be/4DWaAIVlW3k
 Inner Life Of A Cell: http://youtu.be/B_zD3NxSsD8