Transcript Are All Cells Alike?

1. List the four
biomolecules we
studied.
2. State the function
(job) of each biomolecule.
3. Draw and label an
enzyme, substrate, &
active site
Are All Cells Alike?
All living things are made up of cells.
Some organisms are composed of only one
cell. Other organisms are made up of
many cells.
1. What are the advantages of a onecelled organism?
2. What are the advantages of an
organism that is made up of many cells?
Cell Theory
• 1. All living things are made of cells.
• 2. New cells are produced from existing
cells
• 3. Cells are the basic unit of structure
and function in living things.
Prokaryotes vs.
Eukaryotes
• Prokaryotes
(bacteria)
have no nucleus
and very few
organelles. DNA is
not contained
• Eukaryotes
(protists, fungi,
plants and animals)
larger,more
complex,DNA is
inside the nucleus
Prokaryotes
DNA is free
floating
No membrane
bound
organelles
Cell membrane
Contain DNA
Eukaryotes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Pro no Eu do Quiz
Compare/contrast prokaryotic cells and
eukaryotic cells. Include what they have in
common as well as the big differences.
Pro no Eu do Quiz
1. What does Pro no mean?
2. What does Eu do mean?
3. What do both eukaryotes and
prokaryotes have?
Plant Cells Vs. Animal
Cells
• Some structures are
specific to either plant cells
or animal cells only:
– Only plant cells contain:
• Cell wall
• Chloroplasts
• Large central vacuoles
– Only animal cells contain:
• Centrioles
Plant Cells
Vacuole
Chloroplast
Cell
Membrane
Cell wall
Golgi
apparatus
Mitochondrion
Smooth endoplasmic
reticulum
Ribosome
(free)
Ribosome
(attached)
Nuclear
envelope
Nucleolus
Nucleus
Rough endoplasmic reticulum
Animal Cells
Nucleolus
Nucleus
Nuclear
envelope
Ribosome
(attached) Ribosome
(free)
Cell
Membrane
Mitochondrion
Rough
endoplasmic
reticulum
Golgi
apparatus
http://www.youtube.com/watch?v=yKW4F0Nu-UY&feature=related
Smooth
endoplasmic
reticulum
Centrioles
A. NUCLEAR ENVELOPE-REGULATES WHAT ENTERS
AND LEAVES NUCLEUS
B. NUCLEOLUS – PRODUCES RIBOSOMES
C. CHROMOSOMES - CONTAIN GENETIC MATERIAL
(DNA)
Organelle Quiz I
1. Which organelle separates the inside
of the cell from the surrounding
environment?
2. Which organelle is the energy bank
for the cell?
Mitochondria
vs.
Chloroplasts
• Mitochondria make
energy from chemicals
(food molecules)
• Chloroplasts use
energy from light
through photosynthesis
ATP - Life’s
Energy
Currency
Energy is released
when ATP is
hydrolyzed
(broken down) to
ADP.
ATP is restored
from ADP and an
input of energy.
ATP’s energy is
used to drive
endergonic
(energyrequiring)
…RemembeR “ATP”?
• ATP stores energy for cell activities like
active transport & movement within the
cell
Cell Membrane
• Regulates what enters and leaves
the cell and provides support and
protection
• Structure – lipid bilayer with
embedded proteins
Cell Wall
• Provides support and
protection for plant
cell walls
• Made of porous cellulose
so it does not regulate
what enters and leaves
Smooth ER vs. Rough ER
• Rough ER - ribosomes on the ER
make proteins, the ER modifies the
proteins
• Smooth ER - makes lipids
• Ribosomes assemble proteins
Cytoskeleton
• Network of
protein
filaments
• Maintains
shape
• Involved in
cell
movement
Animal Cells
Centrioles
Plant Cells
Cell membrane
Ribosomes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Cell Wall
Chloroplasts
Phospholipids Form Biological Membranes
Fluid-Mosaic Plasma Membrane
•Cholesterol is wedged between
phospholipid molecules in the
plasma membrane of animals
cells.
•At warm temperatures, it
restricts the movement of
phospholipids and reduces
fluidity.
•At cool temperatures, it
maintains fluidity by preventing
tight packing.
Diffusion through Cell Boundaries
• Particles move from an area
of high concentration to an
area of lower concentration
• No energy is required
•For example, if we start with a permeable
membrane separating a solution with dye
molecules from pure water, dye molecules will
cross the barrier randomly.
•The dye will cross the membrane until both
solutions have equal concentrations of the dye.
•At this dynamic equilibrium as many molecules
pass one way as cross the other direction.
Osmosis
• Diffusion of water through a selectively
permeable membrane
Osmosis is the passive transport of water
•Differences in the relative concentration of
dissolved materials in two solutions can lead to
the movement of ions from one to the other.
–The solution with the higher concentration of
solutes is hypertonic.
–The solution with the lower concentration of
solutes is hypotonic.
–Solutions with equal solute concentrations are
isotonic
•In the absence of other forces, a substance will
diffuse from where it is more concentrated to
where it is less concentrated, down its
concentration gradient.
Each substance diffuses down its own
concentration gradient, independent of the
concentration gradients of other substances.
The
solute is more concentrated on the right
side. Which side is hypertonic? How will
dynamic equilibrium be reached?
Isotonic
"ISO" means the same
• Concentration of
solutes (salts) is
the same inside
and outside of
cell.
• Water flows in
and out in equal
amounts
• No effect on cell
Hypotonic
"HYPO" means less
• Concentration of
solutes is less
outside the cell
than in.
• Water flows in
• The cell swell
with water and
becomes “turgid”
Hypertonic
“Hyper” means more
• Concentration of solutes
is greater outside the
cell than inside
• Water flows out of cell
• The cell shrivels and
may die.
• This is why it is
dangerous to drink sea
water
• This is also why "salting
fields" was a common
tactic during war, it
would kill the crops in
the field, thus causing
food shortages.
•For example, Paramecium, a protist, is
hypertonic when compared to the pond
water in which it lives.
–In spite of a cell membrane that is
less permeable to water than other
cells, water still continually enters the
Paramecium cell.
–To solve this problem,
Paramecium have a
specialized organelle,
the contractile vacuole,
that functions as a bilge
pump to force water out
of the cell.
As a plant cell looses water, its volume
shrinks.
•Eventually, the plasma membrane pulls away
from the wall.
•This plasmolysis is usually lethal.
Facilitated Diffusion
•Many polar molecules and ions
that are normally impeded by the
lipid bilayer of the membrane
diffuse passively with the help of
transport proteins that span the
membrane.
•The passive movement of
molecules down its concentration
gradient via a transport protein is
called facilitated diffusion.
Transport proteins allow facilitated diffusion
Active transport is the pumping of
solutes against their gradients
•Some proteins can move solutes against
their concentration gradient, from the side
where they are less concentrated to the
side where they are more concentrated.
•This active transport requires the cell to
expend its own metabolic energy.
Endocytosis
• Cell takes material into cell by infolding of the cell
membrane
• Phagocytosis – eating – cell engulfs large particles
• Pinocytosis – drinking – cell takes in liquid
• www.endocyte.com/ animation/animation.htm
Cell Differentiation – THE PROCESS BY WHICH CELLS
CHANGE
Cell Specialization – TO BECOME WELL SUITED TO
PERFORM DIFFERENT FUNCTIONS.
Levels of
Biological
Organization
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Organism
Organ system
Organ
Tissue
Cell
Organelle
DNA
Atoms