Lab 2 - Microscopy and the Cell
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Transcript of Lab 2 - Microscopy and the Cell
Microscopy and the Cell
Laboratory Session 2
Viewing Cells
The Microscope
"Micro“ – very small “Scope" – to view Microscopes:
instruments used to magnify images of small objects/ specimens
Microscope from: http://biology.unm.edu/ccouncil/Biology_203/Images/Microscopes/microscope6.jpeg
The Microscope
There are four main types of microscopes: Dissection Compound Scanning electron microscope Transmission electron microscope
The Microscope Unlike a hand held lens
(10x), the compound microscope has two
lens for greater magnification (1000x).
Microscope from: http://biology.unm.edu/ccouncil/Biology_203/Images/Microscopes/microscope6.jpeg
The Microscope
Eyepiece – the part you look through. It contains the ocular lens which is usually 10x power.
Tube – connects ocular lens to the objective lens.
Objective lens – the lens closer to the object. Usually there will be 3 or 4 objective lenses on a microscope consisting of 4x, 10x, 40x and 100x powers.
Microscope from: http://biology.unm.edu/ccouncil/Biology_203/Images/Microscopes/microscope6.jpeg
Calculating Magnification
MicroscopeMagnification power of the microscope is the
product of the magnifications of all the lenses in the system
E.g. 10x ocular lens and 40x objective lens would give a magnification of 10 x 40 =
400x.
The Microscope
Coarse focus: A knob that moves the tube up and down to focus the microscope on the specimen.
Fine focus: Another knob that moves the tube small distances for the final focus of the lens.
Microscope from: http://biology.unm.edu/ccouncil/Biology_203/Images/Microscopes/microscope6.jpeg
The Microscope
Stage: The flat platform where sides are placed for observation. Clips hold the slides in place and if mechanical, you will be able to move the slide.
Illuminator – the light source .
Microscope from: http://biology.unm.edu/ccouncil/Biology_203/Images/Microscopes/microscope6.jpeg
The Microscope
Arm - Supports the tube and connects it to the base. It is also used for carrying the microscope.
Base: The bottom of the microscope, on which the instrument stands
Microscope from: http://biology.unm.edu/ccouncil/Biology_203/Images/Microscopes/microscope6.jpeg
The Cell
The Cell
You can only view three parts of a cell under the light microscope: the
Nucleus Cytoplasm Cell membrane
nucleus
cytoplasm
cell membrane
Cheek cells from: http://www.marianopolis.edu/sites/library/sites/Bio-NYA%20pics/Cheek%20cells.JPG
The Cell However, you can
view the organelles with a high resolution microscope called the transmission electron microscope.
Plasma cell from: http://missinglink.ucsf.edu/lm/IDS_101_histo_resource/images/cell_structure_lab_micrograph_B-labelled.jpg
Cell Organelles
A Typical Animal Cell
Animated cell from: http://kconline.kaskaskia.edu/bcambron/Biology%20117/Cells_files/image014.jpg
The Cell Factory
The functions of a cell are usually compared to the workings of a factory
The cell membrane
The CELL MEMBRANE – the gate of the factory.
The cell membrane is selectively permeable allowing only certain substances to enter or leave.
Cell membrane from: http://library.thinkquest.org/C004535/media/cell_membrane.gif
The Cell Factory The NUCLEUS – the Chief
Executive Officer (CEO) The nucleus controls all
cell activity and determines what proteins are to be made. It also stores plans for proteins that the cell currently makes or has made in the past.
Cell nucleus from: http://missbakersbiologyclasswiki.wikispaces.com/file/view/nucleusfigure1.jpg/50510511/nucleusfigure1.jpg
The Cell Factory
The CYTOPLASM – the factory floor.
The cytoplasm is the place where most of the cells activity takes place. It is the jelly like substance situated between the cell membrane and the nucleus and contains the organelles.
Cell ctyoplasm from: http://sciencecity.oupchina.com.hk/biology/student/glossary/img/cytoplasm.jpg
The Cell Factory
The ENDOPLASMIC RETICULUM – the assembly line.
It is a network of communication channels passing between the nucleus and the cytoplasm
Endoplasmic reticulum from: http://www.ccs.k12.in.us/chsBS/kons/kons/eukaryotic%20cell/cytoplasm_and_its_associated_str.htm
The Cell Factory
The Endoplasmic Reticulum provides a platform on which the workers assemble different kinds of proteins as designed by the “CEO”
Endoplasmic reticulum from: http://www.ccs.k12.in.us/chsBS/kons/kons/eukaryotic%20cell/cytoplasm_and_its_associated_str.htm
The Cell Factory
The GOLGI APPARATUS – the finishing and packing department.
The final touches are put on by the golgi. Workers inspect the products for flaws, rid them of any extra material added during their manufacture and wrap them for packing.
Golgi apparatus from: http://missbakersbiologyclasswiki.wikispaces.com/file/view/nucleusfigure1.jpg/50510511/nucleusfigure1.jpg
The Cell Factory
The LYSOSOMES – maintenance crew.
Every factory needs a good maintenance crew to keep clean up the trash and to dismantle and dispose of outdated machinery. These are the lysosomes.
The lysosomes also act as a second line of defense, destroying trespassers as they enter.
Lysosome from: http://www.daviddarling.info/images/lysosome.gif
The Cell Factory
The MITOCHONDRION – the power plant.
The main function of the cell is to build proteins but this requires energy. The mitochondria of the cell is responsible for producing that energy.
Mitochondrion from: http://www.cartage.org.lb/en/themes/sciences/zoology/animalphysiology/anatomy/animalcellstructure/Mitochondria/mitochondria.jpg
Cell Specialization
The discussion so far has been about typical cells, but most cells are anything but typical. The design and shape of a cell is very much dictated by its function and the conditions under which it works.
Cell Specialization
Red blood cells
Cuboidal cells
Neuron
What system do these cells belong to?
Cell Specialization
Sperm and egg
Liver cells
Smooth muscle cellsWhat system do these cells belong to?
Cells Division
Mitosis
Mitosis
Mitosis: is a process whereby a cell divides into
two identical daughter cells has four main phases - P,MAT -
prophase, metaphase, anaphase and telophase
Mitosis
Note: Interphase is not part of mitosis but normal cell activity and preparation that occurs before mitosis
Mitosis diagram from: http://healthinfoispower.files.wordpress.com/2008/09/cell-division.jpg
Mitosis
Onion root tip from: http://www.lima.ohio-state.edu/biology/images/apical_meristem.jpg
Transport of Materials across the Cell Membrane
Passive vs. Active Transport
Transport methods are grouped according to their energy requirements.Passive transport – does not require energy
from the cellActive transport – requires energy from the
cell, usually in the form of ATP
Passive Transport
Diffusion – the movement of particles from an area of high concentration to an area of low concentration
Diffusion from: http://commons.wikimedia.org/wiki/File:Diffusion.gif
Passive Transport
Osmosis – the movement of water molecules from an area of high concentration to an area of low concentration
Osmosis from: http://library.stratfordhall.bc.ca/osmosis_files/osmosisdiffusion.gif
Passive Transport
The effect of osmosis on red blood cells
Osmosis from: http://library.stratfordhall.bc.ca/osmosis_files/osmosisdiffusion.gif
Passive Transport
Facilitated Diffusion – the movement of particles through a carrier protein
Facilitated diffusion from: http://www.bio.miami.edu/~cmallery/150/memb/c8.7x15.facilitated.diffusion.jpg
Passive Transport
Filtration – the use of hyrdostatic force to move water or a dissolved substance across a membrane.
Filtration from: http://www.actions-traitements.org/local/cache-vignettes/L402xH277/kidney_filtrate-e9a33.gif
Active Transport
Active Transport – the use of ATP to move substances against their concentration gradient
Active transport from: http://kenpitts.net/bio/images/active_transport.gif
Active Transport
Exocytosis – the transfer of substances out of the cell
Osmosis from: http://kenpitts.net/bio/images/exocytosis.gif
Active Transport Endocytosis – the transfer of substances into
the cell Phagocytosis – bacteria and other large subsatnces Pinocytosis – water and dissolved stubstances
Endocytosis from: http://www.yellowtang.org/images/endocytosis_1_c_la_784.jpg
THE END
Complete the Worksheet
Microscopy and the Cell
References
The Microscope: Parts and Specifications http://www.microscope-microscope.org/basic/microscope-parts.htm Accessed 21/02/2010
Apex Learning Inc. A Busy Factory. Beyond Books, 2007. http://www.beyondbooks.com/lif71/4a.asp Accessed 21/02/2010
Comparing the cell to a factory http://www.sciencenetlinks.com/pdfs/cellsystem_anskey.pdf Accessed 21/02/2010