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Cellular Level of Organization
CHAPTER 3
Cell Theory by Schledin,
Schwann and Virchow
All organisms are made of
cells
Cells are the basic unit of
life
 All cells come from
existing cells
Figure 3–1
Kinds of cells
 Animal cells are round shaped
 Two types of cells:
 PROKARYOTES: No nucleus.
 EX: Bacteria and algae
 EUKARYOTES: Has a nucleus
 EX: Human
The Cell Membrane
Hydrophilic
head
Hydrophobic tail
Protein within the cell
membrane
• Integral- Proteins that are embedded within
the membrane and cannot be removed
without damaging the membrane itself.
• Peripheral- Those membranes that are
connected to the surface of the membrane
(inside or outside) and can be removed
without hurting the membrane
Important Functional Proteins
•
Anchoring Proteins-stabilize the position of the cell. Inside
they attach to the cytoskeleton. Outside they attach to
neighboring fibers or cells.
•
Recognition Proteins-these are identifiers that let the
immune system know they are normal and presence is
needed.
•
Receptor Proteins-these are sensitive to ligands which are
as small as ions like Ca+ or larger ligands like insulin.
More Important Proteins
•
Carrier Proteins-bind to solutes and carry them in or out of
the cell. Most times this function takes ATP (energy) for the
carrier proteins to do their job.
•
Channel Proteins-Contain a central pore that permits
movement of molecules across the membrane. Very specific
to the molecule that travels through lock-n-key relation.
How do cells eat and drink?????
PASSIVE
Facilitated
Diffusion
TYPES OF TRANSPORT
ION PUMPS
DIFFUSION
OSMOSIS
ACTIVE
EXOCYTOSIS
ENDOCYTOSIS
Phagocytosis
TO EAT
Pinocytosis
TO DRINK
Diffusion
Molecules move from H to L
concentrations
Equilibrium
Osmosis
Water moving through a semi-permeable membrane
because of solute concentrations
Water goes from High concentrations to Low concentrations
TYPES OF SOLUTIONS
• Hypotonic: Low solute on the outside of cell
causing the water to rush into the cells to reach an
equilibrium….cell could lyse (explode)
• Hypertonic: High solute on the outside causing
water to leave cell and cell dehydrates (crenate)
• Isotonic: Cell and solute are at an equilibrium.
Osmotic Conditions
CHANGES IN TRANSPORT
• 3 things can change a cell’s transport
• TEMPERATURE: increased temp causing
transport to increase
• PRESSURE: increased pressure (make area
smaller) increases transport
• CONCENTRATION: increased amounts of
solute will increase the transport
ENDOCYTOSIS AND EXOCYTOSIS
Pinocytosis
Phagocytosis
Facilitated Diffusion
Molecules are moved
Carrier Proteins
with carrier proteins
from high to low
concentrations
Pinocytosis
• Pinocytosis (cell drinking)
• Endosomes “drink” extracellular flui
Endocytosis
Phagocytosis
Cytoplasm
•
Has to parts within it...
•
Cytosol- intracellular fluid that contains dissolved
nutrients, ions, soluble and insoluble proteins and
waste products.
•
Organelles-structures that are suspended within
the cytosol that perform a specific function for the
cell.
Organelle Types
•
Nonmembranous organelles-not contained in a membrane
and directly in contact with the cytosol.
•
Membranous organelles- isolated from the cytosol with a
phospholipid barrier like the cell membrane and performs a
specific task for the survival and function of the cell.
Cytoskeleton
•
Provides strength and stability to
the cytoplasm.
•
Microfilaments
•
Intermediate Filaments
•
Microtubules-largest of the
three
•
spindle fibers for mitosis
•
create centrioles and cilia
Cilia/Microvilli
•
Cilia-beat to move particles
around the membrane or to
move small microscopic
organisms.
•
Microvilli-help increase the
surface area of a cell
membrane for those
membranes that specialize
in absorbing materials.
Example: Small intestine
Ribosomes
•
Site for protein synthesis
•
mRNA created by DNA binds
to the organelle.
•
tRNA will have a
complementary code to
transfer amino acids.
•
Amino acids will form
polypeptide chains that create
proteins.
•
Codons (mRNA)- Anticodons
(tRNA)
Endoplasmic Reticulum
Smooth ER1.) Synthesize certain
carbohydrates, lipids
and proteins.
2.) Store molecules
from the cytosol.
3.) Materials travel from
place to place through it
4.) Drugs and toxins are
absorbed and
neutralized
Rough ER1.) Covered with ribosomes
2.) Modify newly formed
proteins from ribosomes and
packaged for export to Golgi
Apparatus.
Golgi Apparatus
•
3 Major Functions-
•
packages enzymes for
release through exocytosis
•
renews or modifies the cell
membrane
•
packages special enzymes
within a vesicle for use
within the cytosol
Lysosome
•
Provide an isolated
environment for cells
to break down old
organelles and
organic compounds
with power enzymes
that would damage
or kill the cell.
•
Extracted materials
through exocytosis.
Mitochondria
•
Unique organelle that
contains a double
membrane.
•
Outer layer protects
from the cytosol
•
Inner layer contains
Cristae which
surrounds the matrix
of inner fluid that
contains material that
will produce energy
for cellular activity
Cellular Respiration
C6H12O6 + 6O2 -- 6CO2 + 6H2O + ENERGY
RELEASED
(ATP)
Make sure you are able to label each part of the equation
and can identify each molecule!!!
Nucleus
•
Only organelle to be
visible under a light
microscope
•
Contain DNA and the
genetic codes for genes
that code for the traits of
each individual cell
•
All genes are composed
within structures called
Chromosomes
•
Each gene contains a
genetic code for a
particular trait
DNA is contained within Chromosomes
•
2 Chromatids connected by
a centromere
•
23 pairs in each human cell
•
genes encode for specific
traits within specific genetic
codes
•
traits are expressed when
the gene code produces a
specific protein.
Cell Differentiation
• Cells specialize or
differentiate:
• to form tissues
(liver cells, fat
cells, and
neurons)
• by turning off all
genes not needed
by that cell
Cell Specialization
• Cells differentiate
and become cells
that specialize in
a specific task.
• Cells that
specialize
together to
perform tasks are
called tissues.
• Genes
Gene Expression
must produce specific proteins in
order for cells to take form and specialize
in specific tasks.
• Proteins
made allow genes to be
expressed and make us who we are.
• Genes
need to send information to the
ribosomes to make the proteins
necessary for differentiation and
specialization to take place.
Transcription
Translation
CELL CYCLE
Interphase
Mitosis
How long do cells live?
•Muscle cells, neurons rarely
divide and stay with you for your
entire life
•Exposed cells (skin and
digestive tract) live only days or
hours
Cancer
Metastasis
Figure 3–26
TUMORS
Benign tumor:
• contained
• not life
threatening
Malignant tumor:
-spread into
surrounding tissues
(invasion)
-start new tumors
(metastasis)
7 signs of CANCER
• Change in bowel or bladder habits
• A sore that does not heal
• Unusual bleeding or discharge
• Thickening of lumps
• Indigestion or difficulty swallowing
• Obvious change in wart or mole
• Nagging cough or hoarseness