Download Ch 3 The Cell

Cell Structure
A. There are three basic structures of all
types of cells:
1. Cell membrane
a. Contains a bilayer of lipids
b. Is selectively permeable (allows
only certain molecules through protein
carriers)
2. Nucleus
3. Cytoplasm
Plasma Membrane
Separates intracellular fluids from
extracellular fluids
Allows certain substances in and out
Glycocalyx is a glycoprotein are
biological markers by which cells
recognize one another
Cell walls and membranes
video
Fluid Mosaic Model
Double bilayer of lipids with
imbedded, dispersed proteins
Bilayer consists of phospholipids,
cholesterol, and glycolipids
Glycolipids are lipids with bound
carbohydrate
Phospholipids have hydrophobic and
hydrophilic bipoles
Functions of Membrane Proteins
Functions of
Membrane
Proteins
Transport
Enzymatic activity
Receptors for
signal transduction
Functions of Membrane Proteins
Intercellular
adhesion
Cell-cell
recognition
Attachment to
cytoskeleton and
extracellular matrix
Membrane Junctions
Tight junction – impermeable junction
that encircles the cell
Desmosome – anchoring junction
scattered along the sides of cells
Gap junction – a nexus that allows
chemical substances to pass between
cells
Membrane Junctions: Tight
Junction
Membrane Junctions: Desmosome
Membrane Junctions: Gap Junction
Diffusion
Facilitated Diffusion
Osmosis
Isotonic – solutions with the same
solute concentration as that of the
cytosol
Hypertonic – solutions having greater
solute concentration than that of the
cytosol
Hypotonic – solutions having lesser
solute concentration than that of the
cytosol
Sodium Potassium Pump
Active Transport
Transport of large particles and
macromolecules across plasma
membranes
Exocytosis – moves substance from the
cell interior to the extracellular space
Endocytosis – enables large particles
and macromolecules to enter the cell
Phagocytosis – pseudopods engulf
solids and bring them into the cell’s
interior
Ex. Of Endocytosis
Generation and Maintenance of
Membrane Potential
B. Differences between animal and plant
cells, plant cells have:
1. Chloroplasts
a. Contain pigments that
absorb sunlight.
2. Vacuoles
a. Large containers that store
water.
3. Cell walls
a. Rigid structure(contain
cellulose) surrounding the cell.
1. Nucleus
a. “Boss” of the cell.
b. Contains the genetic material of
an organism=chromosomes.
c. Surrounded by a nuclear
envelope with pores (openings).
d. Contains the nucleolus which
makes ribosomes.
e. Cells or organisms with a
nucleus (area that contains the DNA
with a surrounding nuclear envelope)
are called eukaryotic.
f. Cells or organisms without a
nucleus (DNA not contained within a
nuclear envelope) are called
prokaryotic.
1. Ex. bacteria
Nuclear Envelope
Selectively permeable double
membrane barrier containing pores
Outer membrane is continuous with
the rough ER and is studded with
ribosomes
Pores regulate transport of large
molecules into and out of the nucleus
The Nucleus Video
Nucleoli
Dark-staining spherical bodies within
the nucleus
Site of ribosome production
Acts like the “assistant to the boss”
Chromatin
Threadlike strands of
DNA and histones
Arranged in
fundamental units called
nucleosomes
Form condensed,
barlike bodies of
chromosomes when the
nucleus starts to divide
Cell Cycle
Interphase
Growth (G1), synthesis (S), growth (G2)
Mitotic phase
Mitosis and cytokinesis
Interphase
G1 (gap 1) – metabolic activity and
vigorous growth
G0 – cells that permanently cease
dividing
S (synthetic) – DNA replication
G2 (gap 2) – preparation for division
2. Cytoplasm
a. The area between the nucleus and
the cell membrane.
b. Holds all the organelles in
place.
c. Gives shape to the cell.
3. Centrioles
a. Structures that aid in cell
division.
b. Found in the nucleus.
Centrioles Video
4. Mitochondria
a. Known as the “power
house” of the cell.
b. Converts food into ATP to
be used as energy.
c. ATP= Adenosine
Triphosphate
(Adenine plus three phosphate
molecules.)
5. Ribosomes
a. Sites of protein synthesis
(making).
6. Endoplasmic Reticulum=E.R.
a. Passageway that transports
materials throughout the cell.
b. Rough E.R. is studded
with ribosomes.
c. Smooth E.R. is not
studded with ribosomes.
7. Golgi apparatus
a. Passageway that modifies and
packages proteins as they pass
through.
b. Stacked and flattened
membranous sacs (stack of
pancakes)
c. Functions in modification,
concentration, and packaging of
proteins
8. Lysosome
a. Round organelle that rids the cell
of unwanted waste.
b. Digest ingested bacteria, viruses,
and toxins
c. Degrade nonfunctional organelles
Lysosomes video
9. Peroxisomes
a. Detoxify harmful or toxic
substances
b. Neutralize dangerous free radicals
10. Vacuole
a. Containers that hold water and
food for the cell.
Vacuole video
11. Cytoskeleton
a. Contain microtubules and
filaments to add structure to the cell.
Cytoskeleton
Microtubules
Dynamic, hollow tubes made of the
spherical protein tubulin
Determine the overall shape of the
cell and distribution of organelles
Microfilaments
Dynamic strands of the protein actin
Attached to the cytoplasmic side of
the plasma membrane
Braces and strengthens the cell
surface
Attach to CAMs and function in
endocytosis and exocytosis
Intermediate Filaments
Tough, insoluble protein fibers with
high tensile strength
Resist pulling forces on the cell and
help form desmosomes
Motor Molecules
Protein complexes that function in
motility
Powered by ATP
Attach to receptors on organelles
Motor Molecules
12. Cilia and flagella
a. Hair-like projections that help
move some types of cells.
Cilia act like oars
Flagella act like a whip to move the
cell:
Ciliary Action