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Anatomy Unit 4:
Cell Theory &
Cellular Structures
Cell Theory

Term “cell” was coined in 1665 by Robert
Hooke when he looked at a slice of dried
cork. He also observed that:
1.
2.
3.
4.
All living things are comprised of cells.
Cells are the smallest “living” unit in an
organisms.
Cells come from previously existing cells.
Each cell maintains homeostasis
Cell Diversity

Lots of shapes and sizes
Typical Cell
Cell Organization
Cell Organization

The cell includes two basic parts:
1.
2.
Cell Membrane (outer covering of cell)
Cytoplasm

Cytosol (fluid portion of the cytoplasm)

Organelles (cell “organs” or functional
parts)
Cell Organization
Cell Membrane
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Outer boundary
Physical
Chemical
Comprised of two layers of lipid (fat)
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Outer and inner layers
Proteins
Proteins give the cell its unique
“personality” or function
Cell Membrane
Membrane lipids

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The phospholipids in a
cell membrane lie in
two distinct layers.
Hydrophobic tails on
the inside of cell
Hydrophilic heads on
the outside of cell
Function of Membrane Proteins
1.
2.
3.
4.
Transport Channels (in and out of cell)
Receptors
Cell adhesion
Cell recognition
Membrane carbohydrates

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Functions:
Lubrication
Adhesion
Cellular
communication
Cell Illustrations
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Begin Cell Illustrations
Phospholipid bilayer
Cholesterol
Proteins
Lipids
carbohydrates
Membrane Transport
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Permeability
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Impermeable
Freely permeable
Selectively permeable
Passive processes

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Diffusion, osmosis
Filtration
Facilitated diffusion
Active Processes
active transport
vesicular transport
(endo- and exocytosis)

Diffusion
http://www.stolaf.edu/people/giannini/flashanimat/transport/diffusion.swf

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Going from an area of higher concentration
( many collisions) to lower concentration
(fewer collisions).
Concentration gradient
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“Downhill” concentration gradient
Equilibrium does not mean that diffusion stops,
only that transport occurs at equal rates
Passive Transport
http://www.northland.cc.mn.us/biology/BIOLOGY1111/animations/passive1.swf.
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Simple diffusion
Facilitated diffusion
Osmosis
Osmosis and Osmotic pressure
http://www.tvdsb.on.ca/WESTMIN/science/sbi3a1/cells/Osmosis.htm
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Hypertonic

Hypotonic
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Isotonic
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the water diffuses out
of the cell, causing the
cell to shrivel.
the water diffuses into
the cell, causing the
cell to swell and
possibly explode.
the water diffuses into
and out of the cell at
the same rate.
Active Transport

Active transport
occurs when cells
move materials
against their
concentration
gradient, from an
area of lower
concentration to an
area of higher
concentration.

Active transport
requires a cell to
expend or use
energy.
Active Transport
Endocytosis
http://www.northland.cc.mn.us/biology/BIOLOGY1111/animations/passive1.swf
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Requires active
transport.
There are three types of
endocytosis:
Pinocytosis-the
transport of solutes or
fluids.
Phagocytosis-the
transport of large
particles, whole cells, or
solids.
Receptor mediated
endocytosis
Sodium Potassium Pump
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_the_sodium_potassium_pump_works.html
Cellular Illustrations

Please demonstrate active and passive
transports on your cells
Cytoplasm

Is comprised of:
1.
Cytosol (fluid
portion of the
cytoplasm)
2.
Organelles (cell
“organs” or
functional parts)
Cytosol


Intracellular fluid
Contains dissolved nutrients, ions, proteins
and waste products
Cytoskeleton

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Internal protein
framework of various
threadlike filaments
and hollow tubes
Gives cytoplasm
strength and flexibility

Composed of
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Microfilaments
Intermediate filaments
Microtubules
Microfilaments
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Composed of actin
Attached to the cell
membrane by forming
attachments with
proteins in the
membrane
Intermediate filaments
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Intermediate in size
Strengthen cell and
stabilize its position
Microtubules
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Hollow tubes built from
the protein tubulin
Gives cell strength
and rigidity
Anchors most
organelles
Microvilli
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Finger like projections
of the cell membrane
Core supported by
microfilaments
(connects to
cytoskeleton)
Increase surface area
of the membrane
Centrioles
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Cylindrical structure
composed of
microtubules
Aid in cell mitosis
Microtubules in triplets
Each cell has one pair
of centrioles
Nucleus
Nucleus
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Control center of cell
Contains DNA/chromosomes
Genetic repository for ~ 35,000 genes
Genes control the synthesis of proteins in
each cell.
Red blood cells don’t have a nucleus.
Skeletal muscle cells have multiple nuclei.
Nuclear Envelope
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Double membrane
Seperates
nucleoplasm from
cytosol
Filled with
nucleoplasm
Covered in nuclear
pores
Nucleolus
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Center of the nucleus
Synthesize ribosomal
RNA (rRNA)
Most prominent in
cells that manufacture
large amounts of
proteins
Endoplasmic reticulum (ER)
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A network of
membrane-bound
tunnels throughout
the cytoplasm
Connected to the
nuclear envelope
2 types: Smooth and
Rough
ER
Rough ER
Smooth ER
Ribosomes
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Particles attached to
ER are ribosomes.
Ribosomes are the
site of protein
synthesis within
every cell.
Ribosomes
Proteasomnes
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Hollow cylindrical
organelle
Contain proteases
Remove/recycle
damaged or denatured
proteans
Break down abnormal
proteins
Golgi Apparatus
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Flattened membranes
Involved in packaging and secretion of
proteins
Golgi Apparatus
Mitochondria
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Bean shaped
Outer and inner membranes
Mitochondria
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Inner membrane folded into cristae
Adenosine triphosphate (ATP) produced
on cristae.
ATP is high energy compound.
ATP only produced in mitochondria.