Download The cell notes - Elmwood Park Memorial High School

DISCOVERY
• The invention of the microscope
changed the world view of science
forever.
• In the mid 1600’s Robert Hooke put a
microscope together and viewed the
cells of a cork.
• Leeuwenhooke inspired by Hooke
improved his microscope and viewed
living organisms.
First microscope
microscopes
• Light microscope - light passes through one
or more lenses to produce an enlarged
image of a specimen. Can magnify up to
2,000X. Can view living organisms.
• Stains and fluorescent dyes can be added
to show specific structures in the cell.
• Optical techniques can show image in 3D
and computer processing can follow
movements of cell parts and materials in
and out of the cell.
• Image is sharp when 0.2 µm
Compound light microscope
Your compound Light microscope
• Ocular lens 10X
• Low Power 4X multiply 10X ocular
Total magnification is 40X
• Medium is 10X multiply 10 X
Total magnification is 100X
• High Power 40X multiply 10X
Total magnification is 400X
Microscope
• Magnification increases the size of an
object.
• As the magnification increases your
field of view decreases.
• Resolution increases the ability to see
details of the speci.men
• Electron microscope- Forms an image of a
specimen using a beam of electrons rather
than light. Can magnify up to 200,000X.
Must be done in a vacuum. Living organisms
can not survive in a vacuum.
• TEM-Transmission electron microscope
shines a beam of electrons through a thin
specimen.
• SEM-Scanning tunneling microscope runs a
pencil like beam of electrons back and forth
across the surface of the specimen which
produce dramatic three dimensional images.
TEM
TEM Golgi Apparatus
SEM Image
SEM Image
SEM
Sickle Cell
Virus
SEM Images
Dust Mite
Pollen
Cell Theory
• Hooke and Leeuwenhooke
recorded all that they saw.
• Schleiden, Swann, & Virchow
further studied cells and
proposed The Cell Theory.
Page 55.
Cell Theory
1. All living organisms are
composed of one or more cells.
2. Cells are the basic structure and
organization of all living
organisms.
3. Cells come from previously
existing cells, with cells passing
copies of their genetic material
on to their daughter cells.
Cell Size
• A cells size is limited by the ratio of their
outer surface and their inner volume.
• As cells increase their volume (the stuff
inside) Their out membrane stretches (like
blowing up a balloon).
• Too much volume
– Can burst the cell.
– Reduce transport across the outer membrane.
Cell Size
Cell Shape
• Cells can vary in shape depending
on their function
• All cells contain organelles which
are similar in function to human
internal organs.
–The cell membrane surrounds
and protects the cell.
Cell Shape
Two Types of Cells
• Eukaryotic
– Membrane bound nucleus that houses all of the
cells genetic material
– Many membrane bound organelles (p.58).
• Prokaryotic
– No Membrane bound nucleus - the cells
genetic material floats randomly in the cell
– Many organelles NOT bound by a membrane
– Have a cell wall surrounding the cell membrane
Internal Organization
Cell membrane
Cytoplasm
Prokaryotic Cell
Cell membrane
Cytoplasm
Eukaryotic
Cell
Nucleus
Organelles
Compare and Contrast
Prokaryotes
Cell
membrane
Contain DNA
Ribosome
Cytoplasm
Eukaryotes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Prokaryotic Examples
ONLY Bacteria
Prokaryotes
• Cell wall in a bacterial cell is typical made from a
carbohydrate-protein complex called peptoglycan
or similar substance.
• Cytoplasm and cytoskeleton
• Do not contain a nucleus DNA is circular and
DNA area is called nucleoid
• Some bacteria contain plasmids DNA that are
independent of the main DNA. Bacteria can
exchange these. Ex. Plasmid may express allow
a bacteria to express an ability like make a sugar
outer coating.
• Have ribosomes
• Cilia and flagella for movement.
Eukaryotic Example
Venn Diagrams
Compare and Contrast
Animal Cells
Centrioles
Plant Cells
Cell membrane
Ribosomes
Nucleus
Endoplasmic reticulum
Golgi apparatus
Lysosomes
Vacuoles
Mitochondria
Cytoskeleton
Cell Wall
Chloroplasts
•
•
•
•
•
Organelles
Cell membrane
Nucleus
Mitochondrion
Ribosome
Endoplasmic
reticulum
• Golgi apparatus
• Lysosome/perox
isomes
• Microfilament &
microtubules
• Cilia and
flagella
• Cell wall –
Plant cell
• Vacuole – plant
cells
• Chloroplast –
plant cells
Check Point
1.What is the importance of a surface
area to volume ratio?
2. Compare the structure of a eukaryotic
cell with a prokaryotic cell?
3.When Hooke first used the word cell,
did the intend to have it apply to living
material? Explain.
4. Name two structures that all cells
have.
Animal Cell
Cell membrane Fluid Mosaic Model
Proposed in 1972 by Singer
• Selectively permeable & pliable
membrane
• Membrane lipids
– Phospholipids – polar head and nonpolar tails. The polar head are
hydrophilic and the non-polar tails
are hydrophobic
– Steroid (cholesterol) is located
between the tails of the
phospholipids
Cell Membrane
• Proteins embedded in cell
membrane
–Peripheral – external
peripheral proteins have a
carbohydrate attached
–Integral – in between the
phospholipids; can form
channels to allow transport in
and out of the cell
Cell Membrane
• Boundary of the cell
• Made of a phospholipid bilayer
Cell Membrane
Cell Membrane
Nucleus
• Is surrounded by the nuclear
matrix which is a stiff membrane
• There is an inner membrane
called a nuclear envelope
• Chromatin (a combination of DNA
and protein) is inside the nucleus.
The chromatin coils and becomes
chromosomes when the cell is
ready to divide.
Nucleus
• Nucleus stores genetic information
• Is where RNA is copied from DNA
• Nuclear pores allow RNA to travel
out of the nucleus.
• Contains the nucleolus where
ribosome's are made.
Nucleus
• Control center of the
cell
• Contains DNA
• Surrounded by a
double membrane
• Usually the easiest
organelle to see
under a microscope
• Usually one per cell
Ribosome
•
•
•
•
•
Most abundant in the cell
No outer membrane
Is made up of a protein and RNA
Are made in the nucleus
Can be free floating (remain in cell)or
attached to endoplasmic reticulum (for
export).
• Make proteins
• Found in all cells
Ribosome
• Site of protein
synthesis
• Found attached to
rough ER or floating
free in cytosol
• Produced in a part of
the nucleus called the
nucleolus
That looks familiar…what is a
polypeptide?
Endoplasmic reticulum (ER)
• Highway of tubes and sacs by which
molecules move around the cell
• Has a membrane
• Two types
– Rough – is covered in ribosomes is
found in cells that make many proteins
– Smooth – helps make steroids,
regulates calcium in muscles, and
breaks down toxins in the liver
Endoplasmic
Reticulum
• A.k.a. “ER”
• Connected to nuclear
membrane
• Highway of the cell
• Rough ER: studded
with ribosomes; it
makes proteins
• Smooth ER: no
ribosomes; it makes
lipids
Golgi Apparatus
• Processing, packaging and secretion
center
• Is a system of tubes and sacs
• Enzymes that are in the Golgi attach
carbohydrates and lipids to the
proteins.
• Make cell membrane components or
the cell.
• Packages for distribution lysosomes.
Golgi Apparatus
• Looks like a stack of
plates
• Stores, modifies and
packages proteins
• Molecules transported
to and from the Golgi
by means of vesicles
Lysosomes
• Spherical organelles that contain
hydrolytic enzymes which digest
proteins, nucleic acids, lipids and
carbohydrates.
• This allows lysosomes to recycle
cell parts.
• Lysosmoes remain in the cell.
Lysosomes
• Garbage disposal
of the cell
• Contain digestive
enzymes that
break down
wastes
Which organelles
do lysosomes
work with?
lysosomes
• Pump enough H
ion to maintain a
pH of 5.
• Contain about
40 different
enzymes that
breakdown
macromolecules.
Peroxisomes
• Globular organelles found in almost all
eukaryotes but many different types
place where oxidation reactions take
place.
• ex. Breaks down Hydrogen peroxide.
• ex. Brake down of ethanol
• ex. Breakdown of fatty acids
Mitochondria
• Change organic compounds to energy
called adenosine triphosphate (ATP)
• Has two membranes
– Inner membrane called cristae which
increases the surface area so more
compounds can be converted to ATP.
– Outer membrane protects and allows
transport.
• Has its own DNA and can reproduce to
make more mitochondria
Mitochondria
• “Powerhouse of the
cell”
• Cellular respiration
occurs here to
release energy for the
cell to use
• Bound by a double
membrane
• Has its own strand of
DNA (circular)
Cilia and Flagella
• Both organelles are on the exterior of
the cell
• Assist with movement
• Cilia – many short hair-like structures
that beat in unison to cause movement
• Flagellum – one long tail-like structure
that whips to cause movement
Cell Wall
• Cell wall found in fungi, algae,
bacteria, archea, and plants.
Animal cells, and protists do
not
• Rigid outer wall of a plant cell
• Cell growth is limited by the
size of the cell wall
Cell Wall
• Plants cell wall is generally
composed of cellulose
• Lignin and cellulose combine to
form the bark what we refer to as
wood.
• Fungi cell wall is mainly chitin
• Bacteria is mainly peptoglycan
Cell Wall
• Found in plant and
bacterial cells
• Rigid, protective
barrier
• Located outside of
the cell membrane
• Made of cellulose
(fiber)
Cell Wall
Plant Cell Wall
Cell Wall
Vacuoles
• Common in plant cells
• Store enzymes and
metabolic waste
• May be extremely large
Vacuoles
• Large central vacuole
usually in plant cells
• Many smaller
vacuoles in animal
cells
• Storage container for
water, food, enzymes,
wastes, pigments,
etc.
What type of microscope may have
been used to take this picture?
Chloroplasts
• Are surrounded by two membranes
• Contain DNA
• May store starches and fats or contain
pigments used to absorb light for
photosynthesis
• A chloroplast is a plastid
– Contains thylakoids which convert
lights energy into usable energy for
the plant
Chloroplast
• Found only in plant
cells
• Contains the green
pigment chlorophyll
• Site of food (glucose)
production
• Bound by a double
membrane
Chloroplast
Endosymbiotic Theory
• Several key organelles of eukaryotes
originated as symbioses between
separate single-celled organisms.
According to this theory, mitochondria
and plastids ( chloroplasts), and
possibly other organelles, represent
formerly free-living bacteria that were
taken inside another cell as an
endosymbiont.
• Molecular and biochemical evidence
suggest that the mitochondrion
developed from proteobacteria (in
particular, Rickettsiales or close
relatives) and the chloroplast from
cyanobacteria.
• This theory is a partial explanation of
the evolution of eukaryotic cells from
prokaryotic cells.
Cytoplasm and Cytoskeleton
• Cytoplasm is a semi fluid
material.
• Organelles do not float freely
but are supported by a
cytoskeleton.
Cytoskeleton
• Is made up of:
• Microtubules that look like tubes. But are long
hollow protein cylinders. Provide a rigid skeleton
and assist in moving substances.
•
Microfilaments look like webs these thin
protein threads give the cell shape and allow for
movement.
• Both microtubules and microfilaments slide past
one another allowing organelles to move.
Cytoskeleton
• Acts as skeleton and
muscle
• Provides shape and
structure
• Helps move
organelles around the
cell
• Made of three types
of filaments
Centriole
• Aids in cell division
• Usually found only in
animal cells
• Made of microtubules
Where else have we
talked about
microtubules?
Quick Review
• Which organelle is the control center of the cell?
Nucleus
• Which organelle holds the cell together?
Cell membrane
• Which organelles are not found in animal cells?
Cell wall, central vacuole, chloroplasts
• Which organelle helps plant cells make food?
Chloroplasts
• What does E.R. stand for?
Endoplasmic reticulum