Transcript CELL Structure REVIEW

CELL Structure REVIEW
• Cell Theory/Cell size
• Types of cells:
Prokaryotes VS
Eukaryotes
• Cell Membrane and
how substances move
across the membrane
• Cell Organelles
CELLS AND THEIR
ENVIRONMENT REVIEW
• PASSIVE TRANSPORT
: Diffusion, Osmosis
• Crossing the membrane
• ACTIVE TRANSPORT:
Moving against a
concentration gradient
• Moving in Vessicles
• Membrane Receptor
Proteins
Cell Theory
• 1) All Living things
are made of one or
more cells
• Cells are the basic
units of life
• All cells come from
existing cells
Cell Size
• Small cells can
exchange substances
more readily than
large cells because
small objects have a
higher surface area to
volume ratio than
larger objects
• SMALL CELLS
FUNCTION MORE
EFFICIENTLY THAN
LARGE CELLS.
• 100 TRILLION
CELLS IN HUMAN
BODY
Common features of cells
• Cell Membrane:
Encloses the cell and
separates the cell
interior, the
cytoplasm, from its
surroundings.Regulate
s what enters and
leaves the cellsincluding gases,
nutrients and wastes.
• Cytoskeleton: Small
fibers in cell providing
structural support.
• Ribosomes:Cell
structures where
proteins are made.
• DNA:Provides
instruction for making
proteins and allows
cell to reproduce.
PROKARYOTES
•
• Smallest, simplest
cells.
• Single celled organism
that lacks a nucleus
and other internal
compartments.
(Therefore, not able to
carry our specialized
functions)
• 3.5 billion yrs old
Prokaryotes continued
•
• For two billion yrs,
they were the only
organisms on earth.
• Bacteria=most
common prokaryote.
Can cause infections
and cause food to
spoil.
Characteristics of a Prokaryote
• They can live in a broad
range of environmental
conditions.
• Many grow and divide
rapidly.
• Some do not need
oxygen to survive.
• Some make their own
food.
• Circular molecule of
DNA.
• Have Cell Wall
• Some have
polysaccharide capsule
• Flagella
Eukaryotic Cell
• Evolved 2.5 billion yrs
ago.
• NUCLEUS!
• Has internal
compartments called
organelles!
• Cilia and/or flagella
• Cytoskeleton (Actin
fibers, Microtubules,
Intermediate fibers)
Eukaryote continued
• Cell membrane: Fluid
like soap bubbles!
• Double layer of polar
heads and non polar tails
• Allows lipids and
substances that dissolve
in lipids to pass through.
• Contains different kinds
of proteins.
Membrane proteins of cell
membrane
• Proteins are made of
amino acids. Some amino
acids are polar and some
are non polar. This
attraction holds the
proteins in the bilayer.
• MARKER PROTEINS:
attach to carbohydrate on
the surface and advertise
the cell type.
• Receptor PROTEINS:
bind specific
substances , such as
signal molecules,
outside the cell.
• TRANSPORT
PROTEINS: Help in
movement of
substances in/out of
cell.
CELL ORGANELLES to Know
• The nucleus
• Ribosomes
• Endoplasmic
Reticulum (smooth
and rough)
• Vesicle
• Golgi apparatus
• Lysosomes
• Mitochondria
(Mitochondrial DNA)
Plant cell
•
• Features unique to
plant cells (Eukaryotes
too!): Cell Wall
• Chloroplasts
• Central Vacuole
Cells and their Environment
• This section describes
how substances move
through other
substances according
to their concentrations
in solutions. It also
describes how
substances move
across cell membranes
through channels.
•
Passive Transport
•
• Passive Transport:
Movement across the
cell membrane that
does not require
energy from the cell.
• Concentration
Gradient: Difference
in the concentration of
a substance across a
space.
Diffusion and Osmosis: Types of
Passive Transport
• Diffusion: Movement
of a substance from an
area of high to low
concentration, Until
equilibrium is reached.
This is a movement
DOWN the
concentration gradient
• Osmosis: The
diffusion of water
through a selectively
permeable membrane
down a concentration
gradient.
Possibilities for the direction of
water movement:Hypertonic
• If the Fluid outside of
the cell has low
concentration of water
molecules than inside,
then the outside fluid
is hypertonic. The
water will diffuse out
of the cell and the cell
will shrink
•
Hypotonic
• If the fluid outside has
a higher concentration
of water than inside
the cell, Then the
outside solution is
hypotonic and water
will diffuse into the
cell and the cell will
swell!
•
Isotonic Solution
• If the fluid outside the
cell has the same amount
of water concentration
as the fluid inside the
cell, then the fluid
outside is ISOTONIC
and water will diffuse
into and out of the cell at
equal rates. Cell stays
same size.
•
How do polar molecules pass
over the membrane?
• Remember, most ions
and polar molecules
cannot pass across the
cell membranes because
they cannot pass through
the non polar interior of
the lipid bilayer. They
can cross if they have
help from a transport
protein. These proteins
have channels in them.
• Diffusion through ion
channels is still a type
of passive transport!
Facilitated Diffusion
• CARRIER PROTEINS are used to carry
substances across the membrane and release
them on the other side. (Example:
Transporting sugars and amino acids
DOWN the concentration gradient.)
• This transport is called Facilitated
diffusion.
Carrier proteins used to transport
substances
•
Active Transport: Transporting
substances UP the concentration
gradient
• Movement against a concentration gradient.
• Active transport requires the cell to use
energy.
• Most of this energy is supplied by ATP!
Example of Active Transport:
Sodium potassium pump
What about stuff that is too big to
be transported by carrier
proteins?
• Vesicles move large substances across the
membrane.
• Movement of substances into the cell by a
vesicle is called ENDOCYTOSIS
• Movement of a substance out of the cell by
a vesicle is called EXOCYTOSIS.
Cell Cycle
•
Binary Fission
•
Mitosis (PMAT)
•
Meiosis
•