Chapter 7: Cellular
Structure & Function
7.1 Cell Discovery and Theory
7.2 The Plasma Membrane
7.3 Structures and Organelles
7.4 Cellular Transport
7.1 Cell Discovery & Theory
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Objectives:
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Relate advances in microscope technology to
discoveries about cells.
Compare compound light microscopes with electron
microscopes.
Summarize the principles of the cell theory.
Differentiate between a prokaryotic cell and a
eukaryotic cell.
History of the Cell Theory
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1665. ____________
looked at cork (oak bark)
and saw box-shaped
structures.
Called them cellulae.
____________ is the
basic structural and
functional unit of all
living organisms.
The Cell Theory
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1.
2.
3.
Three Principles:
All living organisms are composed of one
or more __________.
Cells are the basic unit of structure and
organization of all living organisms.
Cells arise only from previously existing
cells, with cells passing copies of their
____________________________onto
their daughter cells.
Microscope Technology
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Microscopes have made it possible to see things
even smaller than just cells.
Compound light microscopes: typically ______
lenses
Objects cause light to ______________, which
blurs images
Max magnification: ~1000X
Electron Microscopes
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Transmission: (TEM) uses _____________ to aim
a beam of electrons at thin slices of cells
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Scanning: (SEM) directs electrons over the
surface producing 3D images
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500,000X, dead, very thin, stained with heavy metals
Still must be _____________.
Scanning Tunneling: (STM) 3D computer images.
Can be ___________ specimens!
Basic Cell Types
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All have one thing in common: the
____________________________!!
Special boundary that helps control what enters
and leaves cell.
Most cells have genetic material that provides
instructions for making substances the cell needs.
Break down molecules to generate ___________
for metabolism.
Prokaryote v Eukaryote cells: eukaryotes have
_______________ and are one to 100x larger.
Eukaryotic Cells
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Contain a nucleus and other ________________.
_____________________: specialized structures
that carry out specific cell functions.
______________: distinct central organelle that
contains the cell’s genetic material in the form of
DNA.
Prokaryotic Cells
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No nucleus
No membrane-bound organelles.
Most unicellular organisms are prokaryotes.
___________________.
Many scientists believe prokaryotes are similar to
the first organisms on Earth.
7.2 The Plasma Membrane
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Objectives: Describe how a cell’s plasma membrane
functions. Identify the roles of proteins, carbohydrates,
and cholesterol in the plasma membrane.
Function of the Plasma Membrane
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Responsible for __________________________.
Selective permeability: membrane that allows some substances to
pass through while keeping others ____________.
Structure of the Plasma
Membrane
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Phospholipid bilayer: two layers of phospholipids
are arranged ______________________.
Polar head and Nonpolar tail. Polar head _______
water. Nonpolar tail _______ water. Arrangement
allows it to exist in a watery environment.
Phosphate group is what makes the ______ polar.
Water-soluble substances do not move easily
through the plasma membrane because they get
stopped by the nonpolar middle.
Other Components of plasma
membrane
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Cholesterol, proteins, and carbohydrates.
__________________: can be receptors that
transmit signals to the inside of the cell; on the
inner surface they anchor the membrane to the
cell’s internal support structure; if they span the
entire membrane, they can be transport proteins—
move needed substances or waste materials
through the plasma membrane
Other components continued…
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_______________________: positioned
among phospholipids because it’s nonpolar.
Helps prevent the fatty-acid tails of the
phospholipid bilayer from sticking together,
which contributes to the fluidity of the
plasma membrane.
_______________________: Stick out from
the membrane to define the cell’s
characteristics and help cells identify
chemical signals.
Fluid mosaic model
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All of the components can move throughout the
membrane itself.
The phospholipids can move.
Proteins can move around within the phospholipid
bilayer.
7.3 Structures and Organelles
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Objectives: Identify the structure and function of
the parts of a typical eukaryotic cell. Compare
and contrast structures of plant and animal cells.
Cytoplasm & Cytoskeleton:
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__________________: semifluid material inside the
plasma membrane
___________________: supporting network of long,
thin protein fibers that form a framework for the cell
and provide an anchor for the organelles inside the
cells.
Cell Structures
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_________________: Cell’s managing structure.
Contains most of the cell’s DNA.
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Surrounded by nuclear envelope that has nuclear pores
that allow larger-sized substances to move in and out
of nucleus.
___________________: organelles that help
manufacture proteins. Made of two components—
RNA and protein—not bound by a membrane like
other organelles.
__________________: site of ribosome
production within the nucleus.
More Cell Structures
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____________________________: ER,
membrane system of folded sacs and
interconnected channels that serves as the site for
protein (RER) and lipid (SER) synthesis.
__________________________: flattened stack
of membranes that modifies, sorts, and packages
proteins into sacs called vesicles. These vesicles
can fuse with the plasma membrane to release
proteins to the outside environment.
More Cell Structures
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____________________: Temporary storage of
materials within the cytoplasm.
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In plant cells: stores food, enzymes and other materials
needed by the cell.
Most animal cells do not have vacuoles, but if they do,
they are smaller than plant ones.
_________________: vesicles that contain
substances that digest excess or worn-out
organelles and food particles. Also digest
bacterial and viruses that enter the cell.
More Cell Structures
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_________________________: powerhouse of the cell.
Converts fuel particles (mostly sugars) into usable energy.
 Contains its own DNA. This is why we have maternal
DNA.
______________________: organelles that capture light
energy and convert it to chemical energy through a process
called photosynthesis.
____________________: a thick, rigid, mesh of fibers that
surrounds the outside of the plasma membrane in plant
cells. Made of cellulose and allows the plants to stand up!
More Cell Structures
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___________: short, numerous projections that
look like hairs. Motion is similar to oars in a
rowboat.
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Human respiratory tract.
_________________: longer and less numerous.
Move with a whiplike motion.
Composed of microtubules.
In prokaryotes, these structures contain
___________________ and are enclosed by the
plasma membrane.
Comparing Cells
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Plant versus Animal
________________ contain chloroplasts that have
chlorophyll and are able to convert sun energy
into chemical energy (make sugar).
____________ have large vacuoles whereas
____________ cells typically have no vacuoles or
only really small ones.
Finally, _____________ cells have cell walls, and
________________ cells do not.
Organelles at Work
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Transcription and Translation
DNA is transcribed into mRNA in the nucleus
and then it goes to the ER where ribosomes
translate the mRNA into proteins. These proteins
are sent to the golgi packages them in vesicles
and transports them to other organelles or outside
of the cell. These proteins can be used to carry out
cellular processes.
7.4 Cellular Transport
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Objectives: Explain the processes of
diffusion, facilitated diffusion, and active
transport. Predict the effect of a hypotonic,
hypertonic, or isotonic solution on a cell.
Discuss how large particles enter and exit
cells.
_____________________: Net movement of
particles from high to low concentration.
More on Diffusion
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__________________________: condition where
there is continuous movement of particles but no
overall change.
3 factors that affect the rate of diffusion
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_________________________: higher concentrations
allow diffusion to go quicker
_______________________: the higher the temp, the
faster the diffusion
__________________: higher pressure means higher
diffusion rates.
Facilitated Diffusion
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Uses ___________________________to move
other ions and small molecules across the
plasma membrane.
Still uses a concentration gradient…from high
to low, so no energy is needed.
Also known as _________________________.
Osmosis
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Diffusion of ______________ across a selectively
permeable membrane.
You cannot learn biology by the process of
osmosis!!!!
Concentration is defined as the amount of solute
per unit solvent.
Therefore, water will move to an area of higher
solute concentrate to dilute that solution and
strengthen the original solution.
Active Transport
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Movement of substances across the plasma
membrane ______________ the concentration
gradient.
Requires energy.
Uses carrier proteins commonly called pumps.
Helps maintain homeostasis.
Example: sodium potassium ATPase pump.
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Three sodium from inside the cell bind, then uses ATP
to change the shape, allowing sodium to leave, then
potassium binds, a phosphate is released from the
protein, it changes shape, and the potassium is now in
the cell.
Isotonic Solutions
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Iso is Greek for ________________.
The cell is in a solution with the same
concentration of solutes and water.
This cell is at equilibrium and there is no net
movement of water across the plasma membrane.
Hypotonic Solution
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Hyp-O-tonic: think about it blowing up!
Cell is placed in a solution with a lower
concentration of solute.
Therefore, water floods into the cell.
In RBCs, __________________ can occur. (The
cells can actually burst.)
In plants cells, it creates ____________________,
and the plant cells become firmer.
Hypertonic Solution
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The concentration of the solute outside the cell is
higher than inside the cell.
Therefore, the net movement of water is _______
of the cell.
In RBCs, ___________________ occurs. The
cells shrivel up.
In plant cells, the cells shrink smaller than the cell
wall and _____________________ occurs. The
plant wilts.
Endocytosis & Exocytosis
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____________________ is the process by which
a cell surrounds a substance in the outside
environment, enclosing it in a portion of the
plasma membrane, and brings it into the cell.
________________________ is the secretion of
materials at the plasma membrane. The vesicle
fuses with the plasma membrane and the contents
are released outside of the cell.