Download Cells overviewbio_revised - Appoquinimink High School

Microscopes
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Mid 1600s
1665 Robert Hooke
1st Compound Microscope
After looking at Cork
Saw cambers called Cells
Anton Van Leeuwenhoek
Pond water (animalcules)
Cork Cells / Microscopic Animals
• Cork Cells at 100X Magnification / Plankton have limited powers of
locomotion
Scanning Electron Microscope
• SEM is a type of electron microscope that images the samples
surface by scanning it with a high-energy beam of electrons.
Transmission Electron Microscope
• TEM uses a beam of highly energetic electrons to examine objects
very closely, on a fine scale. A TEM shines a beam of electrons
through an object.
Scanning Probe Microscope
• SPM is a branch of microscopy that forms images of surfaces using
a physical probe that scans the specimen.
Microscope practice:
Drawl the 3 specimens you see.
For your first specimen call over
the teacher so she can check your
image
Name of specimen: ___________________
Name of specimen: ___________________ Name of specimen: ___________________
Cell theory
• All organisms are comprised of one cell or
more.
• Cell is the basic unit of life
• All cells come from preexisting cells
What is an organelle?
Membrane bound structures with particular
functions within eukaryotic cells
Types of Organelles
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Nucleus
Cell membrane
Ribosomes
Endoplasmic reticulum
Golgi Apparatus
Lysosomes
Vacuoles
Mitochondria
Chloroplast – Plants only
Cell wall – plants only
Cytoskeleton
Bacteria
cell
Prokaryotic Cells
Organelles:
Have no nucleus- DNA is free floating
Only have:
cell Membrane
Cell wall
Ribosomes
Cytoplasm
Also have flagella or cilia to assist in
moving
Eukaryotic Cells
Have multiple cells:
Plants have:
Cell wall
Chloroplast
And central Vacuole
Animals:
Have all other organelles
that plants have
Cell Wall
• Plants: cell wall is
rigid and made of
fibrils of cellulose
• Bacteria: cell wall is
made up of
polysaccharides and
protein.
Chloroplast
• Captures light energy in plants and
produces glucose in a process called
photosynthesis.
Click on chloroplast
Ribosomes
• Sites of protein synthesis
• Scattered throughout cytoplasm and on
rough ER
• Comprised of protein and RNA molecules
• Provide structural support for RNA during
protein synthesis
Click on
ribosome
Endoplasmic Reticulum
- Rough ER – folded membrane covered in
ribosomes – one of the sites of protein
synthesis
- Smooth ER – folded membrane with no
ribosomes - lipid synthesis
Golgi Bodies
• Composed of six flattened membranous
sacs
• “Packages” and “delivers” proteins
synthesized by ribosomes
• Proteins arrive travel to the Golgi bodies in
vesicles
Golgi Bodies
• They pass through one end
and continue to pass over
the sac until it forms
glycoprotein which is a
protein that has become
chemically processed
• When the altered
glycoprotein reaches
outermost layer, then
bubble-like structures
(vesicles) form and move
through the cell membrane
to the outside of the cell–
exocytosis
Click on golgi bodies
Vacuole
• Storage for the cell- All eukaryotic cells
have but animal cells are much smaller
than vaculoles in plant cells
Mitochondria
• Elongated fluid filled sacs
• Move slowly through cytoplasm and
reproduce by dividing
• Has inner and outer membrane layers
Mitochondria
• Major site of ATP production – ATP are
units of energy a cell can use to function
(much like gasoline is to a car)
Lysosome
• “garbage men” of the cell
• Membranous sacs
• Powerful enzymes that breakdown nutrient
molecules, foreign particles, or dead cell
parts
Microfilaments
• Made of Tiny rods of actin protein that
form meshwork through out the cells body
• Provide cell mobility by enabling the cell to
contract
Click on picture
Microtubules
• Long slender tubes with diameter two to
three times that of microfilaments.
• Interwoven with Microfilaments
• Composed of globular tubulin proteins
Centrosome
• Structure near Golgi Apparatus and
nucleus
• Consists of two hollow cylinders called
centrioles
• Lie at right angles and distribute
chromosomes evenly to new cells during
mitosis.
Cilia
• Motile extensions from certain cells
• Tiny hairlike structures
• Move to and fro, in succession, so that
there is a wavelike motion
Flagella
• Motile extensions from certain cells
• A cell will only normally have one flagellum
• Swim motion, resembles a tail
Cell Nucleus
• Houses genetic material
• Enclosed in a double layer nuclear
envelope – inner and outer lipid bilayer
membranes
• Protein-lined channels called nuclear
pores that allow for certain molecules to
exit
Nucleolus
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Small dense body in the middle of the nucleus
composed largely of RNA and protein
No surrounding membrane
Forms in specialized regions of certain
chromosomes
• Ribosomes form in the nucleolus and move
through nuclear pores to the cytoplasm
Chromatin
• Loosely coiled fibers of DNA and proteins
= chromosomes
• DNA = information for protein synthesis
• Beginning of cell division – chromatin coil
tightly and individual chromosomes
become visible
Cell Membrane Structure
• A phospholipid consists of a
– polar portion, called the head,
– two longer fatty acids, called the tail.
Cell Membrane Structure
http://www.mhhe.com/biosci/esp/2002_general/Esp/default.htm
When mixed with water, the heads are attracted to the
polar water molecules.
The nonpolar tails move as far from water as possible,
and a double layer of phospholipids with tails to the
interior results.
Phospholipid bi-layer of a cell
membrane
Cell Analogy poster