Describe the structural compartmentation of mammalian cells
DESCRIBE THE STRUCTURAL COMPARTMENTATION OF MAMMALIAN CELLS
AND THE DIFFERING FUNCTIONS OF THESE COMPARTMENTS
All mammalian cells are eukaryotic, and whilst the eukaryotic type of cell is not exclusive to mammals, mammalian cells differ from other eukaryotic cells because of the organelles that are or are not present. For instance some plant cells have chloroplasts which are not present in mammalian cells, but both plant cells and mammalian cells are eukaryotic in nature. The term eukaryotic refers to the cell having specific membrane bound organelles, which are not present in prokaryotic cells. The defining feature of a eukaryotic cell is usually its membrane bound nucleus (the exception being the red blood cell) [1].
Because of the sheer number of organelles in eukaryotic cells I will not be describing each independently and fully in this essay. Instead I will first provide an overview of the organelles involved in protein synthesis so as to give a logical order and clearer picture of each independent organelles specific function, and then move on to some of the most important organelles with a more independent function. The membrane that bounds the organelles into specific space is called a phospholipid bilayer. As shown in Fig 1, the bilayer is permeated with different types of protein, glycolipid etc. These allow the transmembrane movement of molecules that would otherwise be unable to permeate the phospholipid bilayer. This is necessary for the correct flow of molecules from one side of the membrane to the other, so the organelle is not starved of vital nutrients or unwanted electrochemical gradient is made, for example.
The nucleus usually the largest organelle in a mammalian cell, and like almost all other organelles is encased within a phospholipid bilayer. The phospholipid bilayer, as can be seen in Fig. 1 has different channels and routes which different molecules can diffuse or be transported through. Unlike most other organelles, which have
AND THE DIFFERING FUNCTIONS OF THESE COMPARTMENTS
All mammalian cells are eukaryotic, and whilst the eukaryotic type of cell is not exclusive to mammals, mammalian cells differ from other eukaryotic cells because of the organelles that are or are not present. For instance some plant cells have chloroplasts which are not present in mammalian cells, but both plant cells and mammalian cells are eukaryotic in nature. The term eukaryotic refers to the cell having specific membrane bound organelles, which are not present in prokaryotic cells. The defining feature of a eukaryotic cell is usually its membrane bound nucleus (the exception being the red blood cell) [1].
Because of the sheer number of organelles in eukaryotic cells I will not be describing each independently and fully in this essay. Instead I will first provide an overview of the organelles involved in protein synthesis so as to give a logical order and clearer picture of each independent organelles specific function, and then move on to some of the most important organelles with a more independent function. The membrane that bounds the organelles into specific space is called a phospholipid bilayer. As shown in Fig 1, the bilayer is permeated with different types of protein, glycolipid etc. These allow the transmembrane movement of molecules that would otherwise be unable to permeate the phospholipid bilayer. This is necessary for the correct flow of molecules from one side of the membrane to the other, so the organelle is not starved of vital nutrients or unwanted electrochemical gradient is made, for example.
The nucleus usually the largest organelle in a mammalian cell, and like almost all other organelles is encased within a phospholipid bilayer. The phospholipid bilayer, as can be seen in Fig. 1 has different channels and routes which different molecules can diffuse or be transported through. Unlike most other organelles, which have
Bibliography: [1] – Molecular Cell Biology, 7th edition 2012, Harvey Lodish, Chris A. Kaiser, Anthony Bretscher, et al. Macmillian Higher Education. [2] – The structure of the nuclear pore complex, The Annual Review of Biochemistry 2011, Hoelz A, Debler EW, Blobel G [3] - http://www.ibiblio.org/virtualcell/textbook/chapter3/nucs2.htm [4] – Frank Schluenzen et al, Structure of Functionally Active Small Ribosomal Subunit at 3.3A Resolution [5] - http://www.unitus.it/scienze/corsonew/lezione11.html [6] – Cell Biology, second edition. Thomas D. Pollard and William C. Earnshaw. Saunders Elsevier. [7] - http://biology.about.com/od/cellanatomy/ss/endoplasmic-reticulum.htm [8] -http://www.bscb.org/?url=softcell/er [9] – Structure and Function of the Nucleolus, Current opinions in cell biology June 11th 1999, Scheer U, Hock R, [10] - http://www.ncbi.nlm.nih.gov/books/NBK21624/figure/A4351/?report=objectonly