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1.2. Ultrastructure of cells
Miltiadis-Spyridon Kitsos Platon IB Diploma
http://www.pathologyoutlines.com/images/salivary/01_21.jpg
The official IB Diploma Biology guide
The resolution of the electron microscopeElectron microscopes have a much higher resolution than light microscopes.
Resolution is defined as the shortest distance between two points on a specimen that can still be distinguished by the observer or camera system as separate entities.
Thus, as the resolution of an imaging system increases the quality and the detail of the image increases as well.
http://www.lab.anhb.uwa.edu.au/hb313/main_pages/timetable/lectures/Image6.gif
https://youtu.be/VWxYsZPtTsIhttp://www.nanoscience.com/files/cache/1cb19595ba7acd226ff2c9d5acea6c10_f280.jpg
The resolution of the electron microscopeElectron microscopes have a much higher resolution than light microscopesFacts• Light wavelengths are in the range of 400-700 nm which limit the
resolution of the the light microscope. • The maximum magnification of an optical microscope is X1000. • A beam of electrons has a wavelength of 2.5 to 12.2 pm, which
permits a higher resolution in the SEM in relation to the light microscope
• The maximum resolution of an electron microscope is 1 nmResolution
mm μm nm
Human eye 0.1 100 100,000
Light microscope 2 X 10-4 0.2 200
Electron microscope
1 Χ 10-6 0.001
1
The ancestors: ProkaryotesProkaryotes have a simple cell structure without compartmentalization
Haemophilus influenzae bacteria attaching to a surface as seen by a scanning electron microscope. Image: Paul Webster, PhD http://www.hearingreview.com/2014/07/scientist-finds-link-antibiotics-bacterial-biofilm-formation-cause-chronic-ear-sinus-lung-infections/
The ancestors: ProkaryotesProkaryotes have a simple cell structure without compartmentalizationProkaryotes= pro + karyon (Greek, nucleus); those without nucleus
https://youtu.be/U-Gyae41L5s
https://youtu.be/KrTwHXbsFcM
The ancestors: ProkaryotesDrawing of the ultrastructure of prokaryotic cells based on electron micrographs
Cell wall
Plasma membraneNucleoid
70s ribosomes
cytoplasm
70s ribosomes
cytoplasm
Cell wall
Plasma membrane
Nucleoid
Pilli
You don’t draw things that you don’t see in the micrographs.
The purpose of this practical is to identify structures by drawing them
http://image.slidesharecdn.com/ibbiology1-150428204627-conversion-gate02/95/ib-biology-12-slides-ultrastructure-of-cells-7-638.jpg?cb=1430655519
Cell division in prokaryotesApplication: Prokaryotes divide by binary fission.
https://d2jmvrsizmvf4x.cloudfront.net/WLR0dWIhSZeBuAJSHwYs_11-02_BinaryFission_0_L.jpg
http://cronodon.com/images/Bacteria_dividing_3b.jpg
http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::500::500::/sites/dl/free/0073375225/594358/BinaryFission.swf::BinaryFission
ProkaryotesMedia
http://www.sheppardsoftware.com/health/anatomy/cell/bacteria_cell_tutorial.htm http://www.wiley.com/college/boyer
/0470003790/animations/cell_structure/cell_structure.htm
http://www.cellsalive.com/cells/bactcell_js.htm https://www.blackwellpublishing.com/trun/artwork/Animations/Overview/overview.html
Cell division in prokaryotesApplication: Prokaryotes divide by binary fission.
https://d2jmvrsizmvf4x.cloudfront.net/WLR0dWIhSZeBuAJSHwYs_11-02_BinaryFission_0_L.jpg
http://cronodon.com/images/Bacteria_dividing_3b.jpg
http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=swf::500::500::/sites/dl/free/0073375225/594358/BinaryFission.swf::BinaryFission
The eukaryotesEukaryotes appeared circa 2.5 billion years ago. Their appearance coincides with the enrichment of the atmosphere with oxygenThe increased availability of oxygen allowed the evolution of more metabolic pathways which yielded more energy to be invested in size and more complex structures
http://www.nature.com/nature/journal/v455/n7216/full/nature07381.html
Read more
http://evolution.berkeley.edu/evolibrary/images/news/grypaniagraph.gif
The Eukaryotes: being compartmentalizedEukaryotes have a compartmentalized cell structure
Compartmentalized: divided into compartments (sur-rounded by a single or double membrane)
Advantages of compartmentalization
• Enzymes and substrates for a particular process are more concentrated.
• Lytic enzymes can be isolated inside a membranous organelle
• Create optimum conditions for a particular process.
• Organelles with their contents can move around in the cell.
Comp1 Comp2
Comp3 Comp4
http://blog.canacad.ac.jp/bio/BiologyIBHL1/files/1197811.jpg
Comp1
Comp2
http://www.cellsalive.com/cells/cell_model_js.htm
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs.
This is a typical annotated sketch of a liver cell. o The sketch is missing a scale baro Can you spot any other
problems?
Now compare this sketch with an actual TEM photo of a liver cell.
Deduce whether the sketch represents accurately the photo
http://www.tokresource.org/tok_classes/biobiobio/biomenu/eukaryotic_cells/liver_cell_500.jpg
http://images.fineartamerica.com/images-medium-large/tem-of-liver-cell-science-source.jpg
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs.
Lysosomes
Nuclear membrane/Nuclear pores
Rough endoplasmic reticulum
Golgi apparatus
Smooth endoplasmic reticulum
80s ribosomes Mitochondria
Nucleolus
http://images.fineartamerica.com/images-medium-large/tem-of-liver-cell-science-source.jpg
Do the same with this sketch
Plasma membrane
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
http://images.fineartamerica.com/images-medium-large-5/nucleus-tem-david-m-phillips.jpg
https://scbiologi.files.wordpress.com/2014/08/nucleus2.jpg?w=444
Nucleus
• Double membrane with pores• Contains the DNA associated with proteins (chromatin)• During interphase, uncoiled chromatin is found
throughout the nucleus• Densely stained areas of chromatin around the edge of
the nucleus • DNA replication• RNA transcription – RNA exits through the pores
http://highered.mheducation.com/sites/0073031216/student_view0/exercise3/anatomy_of_the_nucleus.html
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
http://www1.udel.edu/biology/Wags/histopage/empage/ecu/ecu16.gif
Rough/ Smooth Endoplasmic reticulum
• Consist of flattened membrane sacs - cisternae• Rough endoplasmic has 80s ribosomes attached• Synthesis of proteins for secretion• Following translation, proteins enter the cisternae and
are carried by vesicles towards the Golgi apparatus. • Smooth associated with the metabolism of fats and
steroid hormones• no ribosomes attached
http://highered.mheducation.com/sites/0073031216/student_view0/exercise3/animal_cell.html
http://3219a2.medialib.glogster.com/media/ba/ba809f577d71c8037c41fc1b18ebd07bbb3f4198dbf287dd59c4fb98b38316d8/smooth-and-rough-er.jpg
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
The Golgi Apparatus
• Like ER, consists of flattened membrane sacs - cisternae
• Presence of a large number of vesicles • Processes proteins arriving from the rER. • Most of the proteins will be carried to the membrane
for secretion https://upload.wikimedia.org/wikipedia/commons/a/a9/Human_leukocyte,_showing_golgi_-_TEM.jpg
https://micro.magnet.fsu.edu/cells/golgi/images/golgifigure1.jpg
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Lysosomes
• Spherical organelles, single membrane• Formed from Golgi vesicles• High concentrations of proteins (digestive) enzymes -
densely stained in electron micrographs. • Enzymes are used in breaking down food particles in
vesicles. http://jennarever.weebly.com/uploads/1/3/6/0/13609849/183821_orig.jpg?225
https://micro.magnet.fsu.edu/cells/lysosomes/images/lysosomesfigure1.jpghttp://highered.mheducation.com
/sites/0072495855/student_view0/chapter2/animation__lysosomes.html
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Vacuoles and vesicles
• Organelles with a simple membrane and fluid inside.• Large vacuoles are characteristic features of plant cells.• Food particles in vacuoles (food vacuoles) are digested
with the aid of enzymes found in lysosomes • Unicellular organisms use vacuoles (contractile
vacuoles) to expel excess of water.• Vesicles are very small vacuoles to transport materials
inside the cell.
http://www.doctorc.net/Labs/Lab3/IMAGES/ORG16.JPG
http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/vacuole.jpg
http://learn.genetics.utah.edu/content/cells/vesicles/
• See fluorescent-stained vacuoles travelling in the cytoplasm of a eukaryotic cell.
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Mitochondrion• Spherical or ovoid shape• Double (Inner and outer) membrane• Inner invaginated membranes - cristae. • Inner semi-viscous fluid - matrix • Sites of ATP production during aerobic cell respiration.• Structure and function revisited in Topic 8 (AHL)
http://atropos.as.arizona.edu/aiz/teaching/a204/images/mitochondria.gif
https://upload.wikimedia.org/wikipedia/commons/0/0c/Mitochondria,_mammalian_lung_-_TEM.jpg
Think: Why these mitochondria differ in shape?
https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Animal_mitochondrion_diagram_en_(edit).svg/2000px-Animal_mitochondrion_diagram_en_(edit).svg.png
https://youtu.be/RrS2uROUjK4
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Free (80s) ribosomes • Non membranous structures • Same as ribosomes attached to the rER• 20 nm in diameter• Inner semi-viscous fluid - matrix • Constructed in nucleolus from rRNA and proteins• Structure and function revisited in Topics 3 and 7 (AHL)
http://iws.collin.edu/biopage/faculty/mcculloch/1406/notes/cell/images/ribosome.jpg
https://upload.wikimedia.org/wikipedia/commons/f/f9/The_Biological_bulletin_%2819755382264%29.jpg
https://ka-perseus-images.s3.amazonaws.com/d3027730681b4cda353ea0e3895b6670ce9024ea.png
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Chloroplasts (plant cells only)• Spherical or ovoid shape• Double (Inner and outer) membrane• Stacks of flattened sacs - thylakoids• Inner semi-viscous fluid - stroma• Site of photosynthesis – production of glucose which is
then packed in starch granules. • Structure and function revisited in Topic 8 (AHL)
http://66.media.tumblr.com/tumblr_lurw6vSOYR1r4zla1o1_400.jpg
http://4206e9.medialib.glogster.com/media/be854f6410ca1e5a792c30c0c1782c67b4f5626ff2a1a52d2905627fd760e27a/chloroplast-grana-en.jpg
https://adapaproject.org/images/biobook_images/A000169_chloroplast_struc.jpg
https://youtu.be/cFVsvgiQdx8
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Centriole (animal cells only)• 9 x triplets of cylindrical protein fibres• Organization of the mitotic spindle – anchor point for
microtubules• Microtubules also support cilia and flagella.
http://cache1.asset-cache.net/gc/128558784-transmission-electron-micrograph-of-a-gettyimages.jpg?v=1&c=IWSAsset&k=2&d=6U2k5nAuQXuSn8AU2xzaoMCXF2acj3GMmlsrmYgJJwxKerKK3tW3%2FGeOiTg0hp6K
https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Centriole-en.svg/320px-Centriole-en.svg.png
https://vimeo.com/58347006http://www.discovery.org/multimedia/video/2010/02/centriole-animation/
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Flagellum (animal cells only)• Central bundle of microtubules - axoneme• 9 outer doublet microtubules -one singlet centre• Locomotion
Cillia (animal cells only)• Also used in locomotion• Numerous projections from the plasma membrane• Microtubules
https://upload.wikimedia.org/wikipedia/commons/6/68/Chlamydomanas_reinhardtii_Flagella_5_-_TEM.jpg
Watch: Euglena locomotion-flagellumWatch: Ciliated protozoa
http://remf.dartmouth.edu/images/ciliaTEM/image/lung_cilia_80299-100.jpg
https://youtu.be/jl0TzaWUQWk https://youtu.be/TTbS7_vZLNg
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Cell wall (plant cells only)
• Cell wall is not an organelle but an extracellular component.
• Made of cellulose (polysaccharide) Gives the cell a definite shape and structure. Provides structural support to the cell. helps in osmotic-regulation. Prevents water loss. It prevents the cell from rupturing due to tugor
pressure.
Watch: Plant cell plasmolysis
http://www.doctortee.com/dsu/tiftickjian/cse-img/botany/plant-anat/cell/plant-cell-tem.jpg
https://amit1b.files.wordpress.com/2009/12/cell-wall-diagram.jpg
https://youtu.be/gWkcFU-hHUk
The Eukaryotes: being compartmentalizedDrawing of the ultrastructure of eukaryotic cells based on electron micrographs
Eukaryotes have a compartmentalized cell structure
Microvilli (singular microvillus)
• Finger-shaped plasma membrane protrusions• Increase the cell surface area.• Facing lumen where exchange occurs (e.g., intestinal
mucosa)
Watch: short video on microvilli
https://youtu.be/gWkcFU-hHUk
http://i3.cpcache.com/product/1119289765/intestinal_microvilli_tem_tile_coaster.jpg?height=460&width=460&qv=90
http://study.com/cimages/multimages/16/microvilli.PNG
TasksIdentify as many organelles as you can. Deduce the function of the cell
The Eukaryotes: being compartmentalizedSkill: Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.
Slide concept by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html
Nu. = nucleusMit. = abundant mitochondria – cell with a high energy demandrER = very well developed rough endoplasmic reticulumVes. = many secretory vesiclesAnimal cell (no cell wall) specialized in secretingPancreatic secretory cell
The Eukaryotes: being compartmentalizedSkill: Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.
Slide concept by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html
NU.
rER
Ves.
Mit.
TasksIdentify as many organelles as you can. Deduce the function of the cell
The Eukaryotes: being compartmentalizedSkill: Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.
The Eukaryotes: being compartmentalizedSkill: Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.
NU.
Chl.Va.
CW
Nu. = nucleus, on the side of the cell Va. = Vacuole, large vacuole in the centerChl.= chloroplasts, with thylakoids and lamellasCW=Cell wallPlant cell from palisade mesophyll
1.2.S3 Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.
What organelles can you identify? Think about the role of the organelles that occur most common and deduce the function of the cell.
http://www.vcbio.science.ru.nl/images/tem-plant-cell.jpgSlides by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html
1.2.S3 Interpretation of electron micrographs to identify organelles and deduce the function of specialized cells.
What organelles can you identify? Think about the role of the organelles that occur most common and deduce the function of the cell.
http://www.vcbio.science.ru.nl/images/tem-plant-cell.jpg
Evidence & conclusions:• Cell wall present – must be a plant cell• No chloroplasts – must be found inside the stem or in the roots• Vacuoles relatively small – the cell does not have a storage,
transport or support function• Nucleus relatively large / cell size small – likely to be a new cell
recently undergone mitosis• Possibly recently divided cell tissue from a plant root
Is in fact: a plant cell found at the root-tip
Slides by Chris Painehttp://www.bioknowledgy.info/12-ultrastructure-of-cells.html
EukaryotesMedia
http://www.wiley.com/college/boyer/0470003790/animations/cell_structure/cell_structure.htm
http://www.tvdsb.ca/webpages/brownt12/files/index1.htm
http://learn.genetics.utah.edu/content/cells/insideacell/ http://www.sumanasinc.com/webcontent/animations/content/eukaryoticcells.html