Cell Terms (Prefixes):
1. Cyto – having to do with cells
2. Hypo – below or under
3. Hyper – above or beyond
4. Philic – loving
5. Phobic – fearing
6. Exo
– exit or out
7. Photo – light
8. Endo – into
9. Phag – To eat
10. Pino – To drink
11. Glyco – having to do with sugar
Laminin
Diversity of cells – over 200
different kinds in the human body
alone!
You can be 100% sure that
this will be on the test!
• The 3 postulates of the cell theory:
–All living things are made up of 1 or
more cells
–Cells are the basic unit of life
–All cells come from pre-existing cells
Cells: A quick review
• Cells were discovered
in the 17th century
(late 1660’s) by
Robert Hooke, who
was observing cork
cells (right)
Cells: A quick review
Two different types of
cells:
– Prokaryotic
• lacks a nucleus
• Lacks any membranebound organelles
– Eukaryotic
• Contain a nucleus and
membrane bound
organelles. Two
prominent members are
plant cells & animal
cells
Prokaryotic Cells
• Smallest and
simplest cells
• A prokaryote is any
single celled
organism that lacks a
nucleus and other
membrane bound
organelles.
• Bacterium are the
major example of
prokaryotic cells
Prokaryotic Cells:
3. Have a cell wall
1. Have single(like plants and
stranded,
fungi) that serves to
circular DNA
support and protect
2. NO internal
the cell.
compartments
(no membrane 4. Cell wall made of
peptidoglycan
bound
instead of cellulose
organelles.)
5. Many have a
flagellum
Eukaryotic Cells
•
•
•
Much more complex than prokaryotic cells.
Contain a nucleus and other membranebound organelles
Two major kinds of eukaryotic cells are:
Plant Cells
1. Have a cell wall
composed of
cellulose
2. Have a large
central vacuole
3. Contain
chloroplasts
1. The Cell Wall
-Made of a
polysaccharide
called cellulose.
-Utilized for
structural support;
when the vacuole is
full, turgor pressure
is created and the
plant can maintain
its rigidity because
of the sturdiness of
the cell wall.
2. Vacuole
• Vacuoles can store
metabolic wastes,
some of which are
economically
important to us.
(caffeine, nicotine,
etc.)
• Loss of water = loss
of turgor pressure.
What will happen
then?
3. Chloroplasts
• Site of photosynthesis and
energy production in
plants
• Utilize light energy, CO2,
and H2O to make sugar.
• Equation:
6 CO2 + 6 H2O =
C6H12O6 + 6 O2
What are these compounds?
Animal Cells
• Lack a cell wall,
have a cell
membrane instead.
• Don’t have
cellulose or
chloroplasts
• Vacuole is much
less prominent
CELL ORGANELLES
• Cells contain smaller specialized structures
called organelles.
Plasma Membrane
1. Plasma membrane is a phospholipid bilayer
Plasma Membrane
• Made of a special kind of
lipid called a
“phospholipid”
• Has a hydrophilic head &
two hydrophobic fatty
acid tails
• In a double-layered
configuration commonly
called a “bi-layer”
Plasma Membrane
1. Plasma membrane is
a phospholipid bilayer
2. Fluid-mosaic model
containing:
– Membrane proteins
(channel proteins,
trans-membrane
proteins, receptor
proteins etc.)
– Glycoproteins
(marker proteins)
– Cholesterol
Membrane Proteins
• Various proteins are
located in the lipid
bilayer of the cell
membrane
• Glycoproteins
(marker proteins)
have attached
carbohydrate
groups and can
advertise the cell
type. ( self/other)
Also -hepatic, renal,
cardiac, etc)
Membrane Proteins
• Receptor Proteins recognize extra-cellular
substances
• Transport Proteins (also called channel proteins)
assist in moving substances in or out of the cell;
crossing cell membrane (ex.-sodium/potassium pump)
Membrane Protein Receptors
• “Seeing eye dog” for
the cell
• Tells cell what
molecules are in the
extra-cellular
environment
• Identifies cells to each
other (AIDS virus to
the right)
– NOTES
Movement in Vesicles
• Movement
into the cell
is termed
ENDOcytosis
• Endo = “into”
• Cyto = “cell”
Endocytosis
• Phagocytosis is
one kind of
endocytosis; in
which a cell
engulfs a foreign
body (Immune
response)
• Cells take in
cholesterol
through
endocytosis
• Notes
Movement in Vesicles
• Movement
out of the cell
is termed
EXOcytosis
• Exo = “away
from” or “out
of”
• Cyto = “cell”
Diffusion
• Movement of a substance
from an area of higher
concentration to an area of
lower concentration is called
diffusion.
• Will continue, if allowed to,
until equilibrium is reached
Equilibrium
• Equilibrium is a
condition in which the
concentration of a
substance is evenly
distributed throughout
space.
– Notes
Osmosis is the
diffusion of water
across a
membrane.
Water moves
through special
channels in the
membrane known
as “aquaporins”.
Osmotic Pressure
Osmotic Pressure is
the force exerted on
the membrane as
water moves across it
in an attempt to reach
equilibrium. The farther
out of equilibrium, the
greater the osmotic
pressure, and the more
water will move across
the membrane.
Concentration Gradient
• A difference in the
concentration of a
substance across a
membrane is called a
concentration
gradient.
• If the membrane is
permeable to the
substance, the
concentration gradient
will eventually reach
equilibrium.
Passive
Transport:
• Movement across a
cell membrane that
does NOT require
energy from the cell is
called passive
transport.
• In many animal cells,
water and most fat
soluble (non-polar)
compounds are able to
passively cross the cell
membrane.
Selective Permeability
• The cell membrane is
selectively permeable to
extra-cellular substances
• The cell membrane is
“picky” about who it lets
through the membrane!
(NO polar ions!)
Crossing the Cell Membrane
• Ions, because of
their electrical
charge, have to go
to the gate!
• The gate is called
an “ion channel”.
– Sodium (Na+)
– Potassium (K+)
– Calcium (Ca ++)
– Chloride (Cl-)
Ion channels in a cell membrane
The 2 kinds of “gates” on ion
channels
• Chemical gates
– Activated by a certain
chemical
(Acetylcholine for
example)
• Voltage gates
– Activated by a change
in polarity
-Notes
-Notes
Water movement across the cell
membrane
• Speed of water
movement across the
membrane depends on
the concentraion
gradient. The greater
the difference in the
amount of solutes
(particles) in the
solution, the more water
will flow across the
membrane.
Water movement across the cell
membrane
• Three possible
conditions resulting
from the osmotic
pressure and
concentration
gradient.
– Hypertonic
– Hypotonic
– Isotonic
• Notes
Hypotonic (“Hypo” = less than)
Isotonic (“Iso” = same)
Hypertonic (“Hyper” = more than)
Tonicity
• When a cell swells
until it ruptures, we
call it “cytolysis” or
“plasmolysis”.
• When a cell shrivels
up from loss of water,
we call it “crenation.”
Tonicity in plant cells
Answer:
So, tell me why…
Those
“poles”
• Why does
a crenatedare
erythrocyte
(shriveled
the
cytoskeleton
up red blood cell)
framework
have those little
underneath;
ridges and poles they
jutting out out much
protrude
everywhere?
like a collapsed
– Anyone
have a
circus
tent!
guess?
Ion transport
• An ion’s charge
affects its diffusion
rate across the cell
membrane.
• Typically, the inside of a
cell membrane is more
negatively charged than
the outside.
(Remember, like
charges repel, but
opposites attract.)
Ion Transport
• A negatively charged
ion INSIDE the cell will
diffuse out easier. (Cl-)
• A positively charged ion
OUTSIDE the cell will
diffuse into the cell
easier (drawn in
electromagnetically)
– Na+
– K+
– Ca 2+
+
+
+
+
_
_
+
_
+
_
Inside of cell
membrane is
NEGATIVELY
charged!
_
+
_
_
_
+
_
+
_
_
+
+
+
Outside of membrane is
POSITIVELY charged!
Facilitated Diffusion
• Cells have “carrier
proteins” used to
transport specific
substances across
the cell membrane.
• Used for amino
acids and glucose
• Is a PASSIVE type
of transport (weird,
huh?)
Active Transport
• Passive Transport
can only move
substances DOWN
the concentration
gradient
• To transport
substances
AGAINST the
concentration
gradients requires
ACTIVE transport!
Active Transport
• Requires ENERGY
from the cell,
supplied by ATP
• Trans-membrane
carrier proteins are
utilized; often called
“pumps”
Sodium-Potassium “pump”
• Sodium-Potassium
pump is powered by
the cells ATP
• 3 Sodium ions out of
the cell and 2
Potassium ions into
the cell with each
cycle
Importance of Sodium-Potassium
pump
• 1. Keeps excess sodium
ions from accumulating
inside the cell
(remember, sodium ions
are continually diffusing
into the cell through ion
channels embedded in
the cell membrane).
• Hemolysis Notes
Mitochondria
• “Powerhouse” of the
cell
• Contains some DNA
(circ.) and ribosomes
• Produces the cell’s
ATP (& thus energy)
• Cells that have high
energy requirements
usually have many
mitochondria
Lysosome
• Lysosome acts like the
“stomach” of the cell
– Contains enzymes that
break down proteins,
lipids, carbs, & nucleic
acids
• Absence of working
lysosomes (& the
enzymes it contains) can
lead to cellular waste
storage disorders such
as Tay-Sachs disease
Ribosomes
• Are the workbenches
that proteins are
made on.
• Composed of RNA
and proteins
• “Free” ribosomes
make intra-cellular
proteins
• Ribosomes attached
to the E.R. make
proteins for exocytic
purposes
Endoplasmic Reticulum
Rough Endoplasmic Reticulum
• Called “rough” because
it has attached
ribosomes, looks
“rough” through a
microscope
• Makes proteins for
transport out of the cell
(exocytosis)
• Proteins packaged and
transported out in
“vesicles”; often go to
the Golgi for further
modification.
Smooth Endoplasmic Reticulum
(E.R.)
• Smooth E.R. lacks
ribosomes, and thus
makes NO proteins
• Involved in lipid
synthesis (such as
steroid hormones),
detoxification, and
carbohydrate
metabolism
Golgi Apparatus
• Adds sugar “name tags”
to proteins & lipids to form
“glycoproteins” and
“glycolipids”.
• Products are then sent in
vesicles to other parts of
the cell; their destination
is determined by the
“name tag” that the Golgi
has given them.
– (Ex- Mannose-6-phosphate
is given to mark a protein
as a lysosomal enzyme)
Brennon
“processing and
packaging center
of the cell.”
Cilia & Flagella
Projections from the cell:
1. Cilia are designed to
move things over or
around the cell
2. Flagella are designed to
move the cell itself
through the environment
(Ex: bacteria)
Cilia in the
human trachea
and respiratory
system:
(The hairs
undulate to sweep
debris up & out of
the respiratory
passages)
Ciliary Action (clears out the junk)
An example of bacterial flagella’s
Salmonella w/ many flagella
Flagella:
•
•
E.Coli picture
and model
showing three
easily
distinguishable
flagella
Bacterial flagella
move the cell by
corkscrewing through
the fluid medium in
which they live.
Eukaryotic flagella
are more complex
structures composed
of microtubules that
whip back and forth
for locomotion
Centrioles
• Centrioles are
composed of 9
groups of 3
microtubules.
(9 + 3 arrangement)
• Arrange and
organize spindle
fibers during cell
division.
Packaging and Distribution of
proteins
• Vesicles containing
newly made proteins
move through
cytoplasm from
Rough E.R. to Golgi
Apparatus
• Golgi Apparatus
modifies proteins
(checks folding, or
refolds)
• Golgi then repacks
proteins in new
vesicles and sends
them on
• Either out of the cell,
or to the lysosome (if
tagged w/ Manose-6phosphate)
Nucleus
• Center of the cell,
membrane bound
• Has holes called
“nuclear pores” which
serve as transport routes
into and out of nucleus
• Contains the DNA
(hereditary information),
which is coiled around
proteins called
“Histones”
• Normal humans have 46
chromosomes
Nucleus
• Nuclear pores
have holes
around them
called “Nuclear
Pore Complexes”
(NPC)
• To move through
the NPC,
molecules have to
have the right
“name tag” (5methyl
guanosine)
Cytoskeleton
Cytoskeleton
• Gives the cell
structural support
• Present in all cells
(Eukaryotic &
Prokaryotic)
• Is a dynamic (as
opposed to static)
structure that enables
cell motility and cell
shape.
• Study these for the test:
– Cell Theory
• 3 postulates
– Cell Prefixes & Terms
• From 11 term list; cyto, glyco,
trans, pino, phag, etc.
– Cell Organelles
• Nucleus, Nucleolus, Golgi,
Smooth ER, Rough ER,
Chloroplasts, Cell Wall, Vacuole,
Lysosome, Ribosomes,
Centrioles, Cytoskeleton, etc.
– Cell Environment
• Diffusion, Osmosis, Osmotic
Pressure, Active Transport,
Passive Transport, Ion
Transport, Tonicity (Hypotonic,
Hypertonic, & Isotonic) etc.