Downloaded 13 times
More Related Content
![06atourofthecell-130311053323-phpapp01 [Autoguardado].ppt](https://cdn.slidesharecdn.com/ss_thumbnails/06atourofthecell-130311053323-phpapp01autoguardado-250807125330-0210e941-thumbnail.jpg?width=640&height=640&fit=bounds)
Ultrastructure
- 2. Cell UltrastructureCell Ultrastructure Whatare ultrastructures? Cellular structures that can be seen clearly under the electron microscope that can’t be seen under the light microscope?
- 3. Electron microscopeElectron microscope •Uses beams of electrons to illuminate specimen, rather than light. • Has much better resolution: define • So it is worth using a much higher magnification. • Disadvantages – images are B&W and specimens must be dead.
- 4. Resolution resolved unresolved Which is worthmagnifying? When light passes through apertures e.g. lenses it spreads out, diffracts.
- 7. A light andelectron microscope view Light x 265 e.m. x 6000 (false colour)
- 8. The generalised animalcellThe generalised animal cell Some of these features may not be present in a particular cell. It depends on the type.
- 9. DonDon’’t forget thecell is 3 D!t forget the cell is 3 D! Pictures taken though microscopes tend to give the impression that a cell is 2D.
- 10. and here isa 3D plant celland here is a 3D plant cell
- 11. You need tobe able toYou need to be able to recogniserecognise and know theand know the functionsfunctions of:of: •Cell membrane •Nucleus •Rough endoplasmic reticulum •Ribosomes •Golgi body (apparatus) •Mitochondria •Smooth endoplasmic reticulum •Lysosomes •Centrioles •Microtubules AND in plant cells •Cell wall •chloroplast
- 12. There are twotypes of cell inThere are two types of cell in the the living world…the the living world… EukaryoticEukaryotic Animal cells Plant cells ProkaryoticProkaryotic Bacteria (and archaes)
- 13. UltrastructuresUltrastructures Of eukaryotic cellsOfeukaryotic cells (more complex than prokaryotes)(more complex than prokaryotes)
- 14. Nucleus Nuclear envelope Nucleoplasm DNA Only seenas chromosomes during cell division Nucleolus A very active group of genes involved in the production of materials for the production of ribosomes Ribosomes Outside of nuclear envelope is connected to the rer mRNA
- 15. And using theelectron microscope becomes
- 16. Rough endoplasmic reticulum Functions: •Proteinssynthesised by ribosomes on surface. •Proteins then transported through cisternae •Proteins packaged in shuttle vesicles for transport to Golgi
- 17.
- 18.
- 20. Golgi Body/ apparatus Lysosome Shuttle vesicles Secretoryvesicle Glycoprotein for export at the cell membrane Functions Proteins arriving in shuttle vesicles are processed by addition of short carbohydrate chains. This modification into glycoprotein acts as : •a destination tag to tell the cell where to send the glycoprotein next •and also adds functionality to the protein The modified proteins are then packaged up in vesicles of two kinds
- 21.
- 24.
- 25.
- 26. Smooth Endoplasmic reticulum •Similarstructure to rer but with no ribosomes: usually less of it in a cell than rer. •Contains enzymes involved in the production of lipids including lipid based hormones eg. testosterone •Also contains enzymes for the breakdown of lipids and lipid based chemicals including some drugs. Structure Function
- 27.
- 28. Mitochondria Matrix: Contains enzymes involved inrespiration and the synthesis of ATP Function Uses energy from respiration to make ATP Lots of these in active cells
- 29.
- 30. Summary: click onthe organellesSummary: click on the organelles
- 31. Cell Walls Functions •Prevents thecell bursting when turgid •Gives support to the cell
- 32.
- 33. Chloroplasts Chloroplast Functions Contains chlorophyll for thecapture of light energy for use in photosynthesis Has a complex interior membrane system to which the chlorophyll molecules are attached
- 34.
- 37.
- 39.
- 40. MicrotubulesMicrotubules •Are elements ofthe cytoskeleton. •Are involved in cell movements; e.g. beating of cilia Can act as roads or cellular railway tracks to guide movements of vesicles in cytoplasm e.g. neurotransmitters in neurons.
- 42. Centrioles Organise the assemblyof microtubules to form the mitotic spindle in animal cells. (Sometimes called the microtubular organisation centre). The pair of centrioles must replicate prior to cell division.
- 44. Remember: there aretwo types of cell in the the living world… Eukaryotic Animal cells Plant cells Prokaryotic Bacteria (and Archaes) Eukaryotic cells evolved from symbioticEukaryotic cells evolved from symbiotic relationships between prokaryotesrelationships between prokaryotes
- 45.
- 46. ProkaryotesProkaryotes You must know thedifferences between prokaryotic and eukaryotic cells Prokaryotes are much smaller than most eukaryotic cells
- 47. Cell wall madeof murein not cellulose No nucleus or other organelles DNA circular loop May have capsule: for attachment to surfaces or to prevent desiccation Flagellae for movement Does have ribosomes but smaller than in eukaryotes May have secondary smaller chromosome called a plasmid
- 50.
- 51. Electron microscope viewof aElectron microscope view of a mitochondrionmitochondrion What similarities do you notice between this and the prokaryote in the previous slide?
- 52. Differential Centrifugation To obtainpure samples of functional organelles Isotonic, ice cold solution used Organelles separate on the basis of differences in density at faster and faster centrifugation speeds Know the order in which the organelles sediment: densest first
- 53. You also needto know:You also need to know: The structure of an epithelial cell from small intestine and a palisade mesophyll cell as seen under a light microscope Describe the adaptations of these two cell types to their functions including ultrastructural features