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