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Chapter 4 Blog: General Features of Cells (Maria)

Page history last edited by Maria Chiaffarano 13 years, 8 months ago

In the first section of this page, you will write a daily summary of that day's class.  For example in  your chapter 2 blog, your first entry should be titled 9/3/10.  You should then write a one or two paragraph summary of that day's lecture, outlining the major points.  In the second section, you are required to add two items (link to a website, video, animation, student-created slide show, student-created PowerPoint presentation) and one journal article pertaining to a topic in this chapter.  A one-paragraph summary must accompany each item describing the main idea and how it applies to the lecture topic.  Please see the PBWorks help guide for assistance embedding video and other items directly in the page.  I will also produce a how-to video on using tables to wrap text around items and other useful tips.  Please see the syllabus for organization and grading details.


A.  Daily Blog

Blog for 9/22/10 Lecture


Biology Lecture today made me feel like I have to really sit down and study.  I have been reviewing and most of the things we talk about are review, but I feel like I need to make sure I know them completely, especially for the test.  After years of just memorizing...here comes the critical thinking!


Today we talked about the differences between Prokaryotic and Eukarytoic cells.  We described prokaryotic cells as being a "single room", meaning that there aren't any different or separated compartments such as organelles.  They do not contain a nucleus but they do have a cell wall.  The categories of prokaryotic cells are bacteria and archea. Both are small and abundant, however bacteria is more common.  Archea is mostly found in extreme environments (really hot, freezing, etc.).  Only 1-3% of bacteria have been identified.  (This was a really interesting fact to learn!).    

     However, all cells contain:

          - Ribosomes - responsible for amino acid assembly (protein synthesis)

          - Cytoplasm - fluid in the cell, chemical reactions take place in the cytoplasm  (water - hydrolysis, maintains concentration gradients)

          - Plasma Membrane  (the plasma membrane is very important to the cell!!!!)


Eukaryotic cells are compartmentalized.  This means that they have organelles that are specified and perform unique functions.  For example, the Mitochondria is the power house of the cell and its job is to create and store ATP (energy for the cell).  The shape, size, and organization of cells vary. 


We also learned about Proteome and how it determines cell characteristics.  The proteome is what is expressed within a cell.  The same DNA is found in all cells, however gene expression controls structure and function of cells (proteins).  Translation is polypeptide synthesis; information in a gene is stranslated in an amino acid sequence.  The primary structure of the protein is the most important structure because it determines the other structures and therefore the protein's function as well. 


Finally, we learned about the Endomembrane System.  It is a network of membranes enclosing the nucleus, endoplasmic reticulum, golgi apparatus, lysosomes, and vacuoles.  It includes the plasma membrane.  It passes materials throughout the cell as well as out/into the cell via vesicles.  In other ways, it "shuttles cargo" throughout the cell. 



Blog for 9/26/10 Lecture


During Friday's class, we reviewed Cotranslational modification.  I am really glad that we went over that topic because I was slightly confused when I had read about it beforehand.  Class really helped me understand what it meant and the importance of it. 


 Rough ER -> costranslational modification

  1. DNA in the nucleus
  2. mRNA is produced (copying)
  3. Protein synthesis happens in the CYTOPLASM
  4. Transcription into mRNA
  5. mRNA translation – protein (synthesis)
  6. ribosomes bind to mRNA and amino acid chain is long (N’ terminus is always at the end)
  7. These amino acids have the ER signal sequence (HAVE A SIGNAL)  temporary tag – allows the cell to locate and traffic to its correct compartment
  8. Targeted by SRP
  9. What types of amino acids are most prevalent in the N-terminus of the ER signal sequence :  MOSTLY HYDROPHOBIC.  – character of the amino acid sequence, can interact in hydrophobic or vander walls reactions  

                                                             x.      ******* there are more, mostly nonpolar and polar (uncharged)

  1. SRP – signal recognition particle; it’s a protein.  It binds to the ribosome and brings the amino acid sequence and they all get “shuttled” to the rough ER

                                                               i.      Has a binding cleft  (lock and key)

                                                             ii.      What kind of amino acids line the binding cleft?

  1. Hydrophobic  cleft binds to the hydrophobic part of the amino acid ER signal sequence  (hydrophobic binds to hydrophobic to protect against water, further bury themselves)
  2. Synthesized as being inserted into the lumen (empty space) of the ER
  3. SRP contributes to the ER being “rough”
  4. Secretory protein – insulin (pancreatic)
  5. Membrane protein – receptor for insulin
  6. Disease

          i.      If the first 40 amino acids got deleted (the first 20 are the ER signal sequence), the protein would never be found by SRP and taken to the ER

         ii.      A cell missing the Chlorine channel ^^^^^^  is hypertonic – sucks in water, cannot regulate water

         iii.      ^^^ cystic fibrosis

2)      Cytoplasmic (free ribosomes)

3)      Semi-autonomous – post-translational



B.  Useful Materials


Golgi Apparatus Song! (submitted 9/22/10)


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This video relates to what we are learning in class because it is a song about the Golgi apparatus, an organelle in eukaryotic cells.  The video makes learning about the Golgi both amusing and interesting.  I learned that the Golgi makes and sends out lysosomes.  I also learned that the Golgi receives, modifies, and sends cellular material.  I thought this video was good for a laugh and educational in its own way. 




Journal Article: Inhibitors and Proteins (submitted 9/22/10) 


I could not find an article about protein trafficking specifically, but I did find this article about proteins.  It was an experiment that was using the different functions and structures of proteins to its advantage.  It emphasized the importance of different proteins; their structures and functions.  A step in the procedure of the experiment was to synthesize a series of peptide bonds.  Peptides are strong bonds that are formed between proteins. 




Structure and Function of Cell Organelles  


This web page allows you to click on different parts of the cell in order to learn about the different structures and functions of the organlles.  I liked the web page because it was very organized, showed graphics, and good descriptions.  It relates to lecture because in Chapter 4 we are learning about the cell organelles and their importance to the cell functioning as a whole. 



Comments (1)

Maria Chiaffarano said

at 9:11 am on Sep 23, 2010

Dr. Weber,
I could not find an article about protein trafficking. Please let me know if the article I used will be acceptable. Thank you!

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