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The Nucleus

The Nucleus. Robin Bauman Advanced Bio Mr. Daly. The Nucleus. Highly specialized organelle that serves as the information processing and administrative center of the cell. Two major functions Stores the cell’s hereditary material (DNA) Coordinates cell’s activities

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The Nucleus

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  1. The Nucleus Robin Bauman Advanced Bio Mr. Daly

  2. The Nucleus • Highly specialized organelle that serves as the information processing and administrative center of the cell. • Two major functions • Stores the cell’s hereditary material (DNA) • Coordinates cell’s activities • Include growth, intermediary metabolism, protein synthesis, and reproduction (cell division). • Only Eukaryotes have nucleus.

  3. Electron Micrograph of the Nucleus

  4. The Nucleolus • Membrane-less organelle within the nucleus that manufactures ribosome's. • Large dark spot within the nucleus. • During cell division, the nucleolus disappears. • After cell divides, a nucleolus is formed when chromosomes are brought together

  5. The Nuclear Membrane (Envelope) • A double-layered membrane that encloses the contents of the nucleus • Envelope is perforated with tiny holes called nuclear pores • . • During cell division (mitosis), the nuclear envelope disintegrates, but reforms as the two cells complete their formation.

  6. Nuclear Pores • Nuclear pores regulate the passage of molecules between the nucleus and the cytoplasm.

  7. Works Cited • Molecular Expressions. http://micro.magnet.fsu.edu/cells/nucleus/nuclearenvelope.html • Google Images. http://images.google.com/imghp?hl=en&client=firefox-a&rls=org.mozilla:en-US:official&hs=qtJ&tab=wi

  8. Ribosomes Ribosome is a particle composed of protein and RNA that serves as the site of protein synthesis Found in cytoplasm of prokaryotic and eukaryotic cells Has a large and small subunit that act as one to read the genetic sequence from the mRNA to make proteins “Using the mRNA as a template, the ribosome traverses each codon, pairing it with the appropriate amino acid. This is done through interacting with transfer RNA (tRNA) containing a complementary anticodon on one end and the appropriate amino acid on the other.” • Ribosomes in translation

  9. Large Subunit- mostly RNA, “Proteins are distributed mainly on the surface. Some proteins have long tails that extend into the interior of the complex. These tails, which are highly basic, interact with the negatively charged RNA. The active site domain for peptide bond formation is essentially devoid of protein. The peptidyl transferase function is attributed to the 23S rRNA, making this RNA a ‘ribozyme’.“ Small Subunit- a cleft in the small subunit is the binding site for tRNA. Small subunit is also really flexible and can assume different conformations. In eukaryotes, ribosomes are made up of 4 strands of RNA & are often attached to the membranes of endoplasmic reticulum to form Rough ER In prokaryotes, ribosomes are made of 3 strands of RNA & occur free in cytoplasm Ribosomes in translation 40% protein and 60% ribosomal RNA (rRNA)

  10. Evolution • In the last 50 years, ribosome research has made two significant discoveries: the discovery of mRNA as a molecule in the transmission of genetic information and the “optimization of an in vitro protein synthesis system” • Recent studies have also shown that the secondary structure of the RNA molecules has been “strongly conserved throughout evolution”.

  11. Bibliography • http://www.rpi.edu/dept/bcbp/molbiochem/MBWeb/mb2/part1/trna.htm • http://www.ncbi.nlm.nih.gov/pubmed/6129626 • http://www.springerlink.com/content/q4530g00605138u8/

  12. Ribosomes Marissa Martinez

  13. What are Ribosomes? • Complexes(small brown dots) that make up proteins • There are ribosomes that are in bacteria and eukaryotes. These have different structures but the same functions. • There are free and bound ribosomes - Free: are found in cytosol - Bound: are bound to rough ER or in the nuclear envelope.

  14. Electron Micrograph of Ribosomes

  15. History of Ribosomes First observed in mid-1950’s by Romanian cell biologist George Palade using an electron microscope. George Palade won the Nobel Prize for his discovery. Scientist Richard B. Roberts in 1958 proposed the name “ribosome”.

  16. Structure of Ribosomes Made up of two subunits, called large and small subunits. These subunits consist of proteins and RNA molecules named ribosomal RNA’s (rRNA’s). About two-thirds of the mass of a ribosome consist of rRNA, either three molecules in prokaryotes or four in eukaryote.

  17. Structure of Eukaryote and Prokaryote Ribosomes These subunits are made in the nucleolus The main difference between these two ribosomes is that Eukaryote ribosomes are slightly bigger and slightly differ in their molecular structure. Ribosomes found in chloroplasts and mitochondria of eukaryotes also consist of large and small subunits bound together with proteins. Descendents of bacteria and this is why their ribosomes are similar to bacteria.

  18. Function They are the “workhorses” of protein biosynthesis which is the process of translating mRNA into proteins. Build proteins from the genetic instructions held with the messenger RNA. Translate messenger RNA to build polypeptide chains using amino acids delivered by transfer RNA.

  19. Building sites • Ribosomes have three building sites for tRNA. 1. P-site (peptidyl-tRNA): hold the tRNA carring the growing polypeptide chain 2. A-site (aminoacyl-tRNA): holds the tRNA carrying the next amino acid to be added to the chain. 3. E-site: the exit site where the tRNA leaves the ribosome.

  20. Work Cited • http://i.ehow.com/images/GlobalPhoto/Articles/4752555/114996_Full.jpg • http://en.wikipedia.org/wiki/Ribosome • http://msnbcmedia4.msn.com/j/ap/fa4b24a6-0596-4fec-965a-565ba421981b.widec.jpg • http://micro.magnet.fsu.edu/cells/ribosomes/images/ribosomesfigure1.jpg • Biology Book: by Reece Campbell

  21. The Rough Endoplasmic Reticulum By: Aaron Gjullin

  22. Facts about rough ER • Endoplasmic means “within the cytoplasm” and reticulum is Latin for “little net” • It is a eukaryotic organelle • The rough ER is attached to the nuclear envelope which also has ribosomes.

  23. More Facts about Rough ER • Rough ER is part of the endomembrane system • Its membrane allows for water soluble proteins to pass through into the lumens • The rough ER has ribosomes on the outside of it which read mRNA and make proteins .

  24. Function of the Rough ER • Many cells emit proteins made by ribosomes. (also called secretory proteins) • It folds proteins into their “native” shape • Adds proteins to cell membrane making them integral proteins.

  25. Smooth ER Maja Whitaker September 24, 2009

  26. Organelle • Smooth ER found in the Endoplasmic Reticulum • Membranous network in eukaryotic cells • Differs from rough ER • Tubular structure, rather than disc-like • Surface lacks ribosomes

  27. Form and Function • Metabolic processes • Synthesis of lipids • Fatty acids, phospholipids, lipid-based hormones • Cholesterol/Calcium metabolism • Calcium storage • Detoxification of drugs/poisons • Transport of materials in/out of cell • Controls movement of newly synthesized proteins to proper location in cell or membrane before being sent out of cell • Provides surface area and space for the action of enzymes

  28. Form Fitting Function • Sarcoplasmic Reticulum of muscle cells • Smooth ER stores calcium • Calcium is released during muscle contraction • Movement of a muscle is triggered

  29. Evolutionary Origin of Smooth ER • Endomembrane Hypothesis • Eukaryotic Cell • Endoplasmic Reticulum: one of the organelles that composes the endomembrane system • Continuous with the nuclear envelope • Directly connected to nucleus • Indirectly connected to other organelles through transport vesicles

  30. http://liquidbio.pbworks.com/f/1194817600/endoplasmic%20reticulum.jpghttp://liquidbio.pbworks.com/f/1194817600/endoplasmic%20reticulum.jpg http://academic.brooklyn.cuny.edu/biology/bio4fv/page/rougher.htm

  31. Works Cited • The Endoplasmic Reticulum.http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/ER.html • Rough and Smooth Endoplasmic Reticulum. http://academic.brooklyn.cuny.edu/biology/bio4fv/page/rougher.htm • The Endoplasmic Reticulum Organelle: Function and Appearance of Rough and Smooth ER http://biology.suite101.com/article.cfm/the_endoplasmic_reticulum_organelle

  32. Smooth ER

  33. Structure of the Smooth ER • Connected to the nuclear envelope • The SER consists of a network of tubules and vesicles • The folded network of tubules and vesicles allow for a greater surface to volume ratio • Found in a variety of both plant and animal cells

  34. The SER has functions in several metabolic processes Synthesizes lipids and steroids Synthesizes the metabolism of carbohydrates Regulates calcium concentration Functions of the Smooth ER

  35. Sarcoplasmic Reticulum • A special type of SER found in smooth and striated muscle • The main difference between the SER and the SR is that the SER synthesizes molecules while the SR stores and pumps calcium ions

  36. Works Cited • http://images.protopage.com/view/721389/97hve8xpzxt2j5bgwdbv2adie.jpg • http://en.wikipedia.org/wiki/Endoplasmic_reticulum • http://www.britannica.com/EBchecked/topic/550111/smooth-endoplasmic-reticulum • http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/E/ER.html • http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.2208

  37. The Golgi Apparatus By: Nikki Chase

  38. General Information • The Golgi Apparatus is a membrane-bound organelle that has a single membrane and is made up of a stack of membrane-bound vesicles that take part in the packaging of macromolecules that are to be sent out to other parts of the cell. • It has a cis-face that is able to receive transport vesicles from the Endoplasmic Reticulum • In this cis-face, protein products and lipid bilayers are made into vesicles and distributed to parts of the cell. • The Golgi Apparatus also has a trans-face which is the part of the organelle that sends the vesicles out to the other parts of the cell. http://www.cartage.org.lb/en/themes/Sciences/Zoology/AnimalPhysiology/ Anatomy/AnimalCellStructure/GolgiApparatus/golgi.jpg

  39. Fotografías de Golgi Apparatus http://saturn.med.nyu.edu/facilities/imagecore/gallery/golgi_apparatus.gif http://media-2.web.britannica.com/eb-media/52/116252-004-9615DB80.jpg

  40. The Golgi Apparatus By: Nikki Chase

  41. Transport Vesicles Transport Vesicles are tiny membranous sac in a cell, that are involved in shuttling cargo from the interior of the cell, to the cell surface, and from the surface of the cell to the interior the cell. They also provide movement of materials in and around the cell. Most common example of a Transport vesicle movement, is the transfer of proteins from the rough (ER) to the Golgi Apparatus.

  42. Transport Vesicles Transport vesicle Transport vesicle Transport Vesicles are protected from the cytosol by a least one phospholipid bilayer. Transport vesicles can fuse their phospholipid bilayer with the cell membrane to release waste or other materials outside of the cell. Or can also fuse with other organelles within the cell. Transport Vesicles are from through the Endomembrane Hypothesis. The vesicles are made though the folding of membranes.

  43. Transportation Vesicles Vesicle trafficking- vesicles that travel over a large distance to get to their target. Vesicle tethering- is the liking of a vesicle to its target form a further distance. Vesicle fusion may not always occur. Vesicle docking- docking refers to the holding of two membranes together, and needs to occur for bilayer fusion. Vesicle fusion- the transportation vesicle phospholipidbilayer, attaches to cell membrane or surface of other organelles. The substance inside the vesicles is then released out of the cell or into other organelles of the cell. This fusion process also adds phospholipids to the cell membrane due to the fact that vesicle is completely absorbed to the entire cell membrane.

  44. Transport Vesicles~ Sam Sheppard

  45. Form and Function~ Transport Vesicles, http://academic.brooklyn.cuny.edu/biology/bio4fv/page/tranves.htm

  46. Form and Function~ • Transport vesicles transport molecules between different membrane-enclosed compartments inside the cell. • For example, they transport proteins from the rough endoplasmic reticulum to the Golgi apparatus. • This vesicular transportation therefore maintains the functional organization of the cell. • The membrane-bound and secreted proteins which are made on ribosomes, found in the rough endoplasmic reticulum, exist inside of the cell, which in turn exists inside of the transport vesicles. Vesicle, http://en.wikipedia.org/wiki/Vesicle_(biology) The Mechanism of Vesicular Transport, http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cooper&part=A1511

  47. Form and Function~ • Budding from membrane  Formation of vesicle  cytoplasm surfaces of transport vesicles coated with proteins  vesicle budding/transport based off of assembly of protein coats  • -clathrin-coated vesicles~ take up extra cellular molecules from plasma membrane by endocytosis and transport molecules from trans Golgi to lysosomes (in this vesicle coating process the cell is very selective) • -nonclathrin-coated vesicles~ one class buds from ER and carries cargo along secretory pathway, to Golgi apparatus, the other buds from ER-Golgi intermediate compartment or the Golgi apparatus and in the retrieval pathways they retain proteins in the Golgi and ER. The Mechanism of Vesicular Transport, http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cooper&part=A1511

  48. Evolution~ • The transport vesicle evolution is based off of the endomembrane hypothesis • The endomembrane system of Eukaryotic cells consists of the cell membrane, nuclear envelope, ER system, Golgi apparatus, lysosomes, vacuoles, and vesicles • Within the cytoplasm of the cell inside the endomembrane system exist transport vesicles Endomembrane System, http://academic.brooklyn.cuny.edu/biology/bio4fv/page/endomem.htm

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