Chapter 6- Cell Structure

Chapter 6- Cell Structure - 1/14/2010 CellStructure 2010:...

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1/14/2010 1 Cell Structure © 2010: D. Julian Cells: the fundamental units of life All organisms are made of cells. The cell is the simplest collection of matter that can live. Cell structure is correlated to cellular function. All cells are related by their descent from earlier cells. © 2010: D. Julian Comparing prokaryotic and eukaryotic cells Basic features of all cells: Plasma membrane Semifluid substance called cytosol Chromosomes (carry genes) Ribosomes (make proteins). © 2010: D. Julian
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1/14/2010 2 Fimbriae Nli d Basic structure of prokaryotic cells Prokaryotic cells are characterized by having No nucleus DNA in an unbound region called the nucleoid No membrane bound organelles Cytoplasm bound by the plasma membrane Nucleoid Ribosomes Plasma membrane Cell wall Capsule Flagella Bacterial chromosome (a) A typical rod-shaped bacterium (b) A thin section through the bacterium Bacillus coagulans (TEM) 0.5 μm © 2010: D. Julian Eukaryotic cells A eukaryotic cell has internal membranes that partition the cell into organelles. Plant and animal cells have most of the same organelles. Eukaryotic cells are characterized by having DNA in a nucleus that is bounded by a membranous nuclear envelope Membrane bound organelles Cytoplasm in the region between the plasma membrane and nucleus Eukaryotic cells are generally much larger than prokaryotic cells. © 2010: D. Julian The plasma membrane The plasma membrane is a selective barrier that allows sufficient passage of oxygen, nutrients, and waste to service the volume of every cell. TEM of a plasma membrane (a) Outside of cell The general structure of a biological membrane is a © 2010: D. Julian (b) Structure of the plasma membrane Inside of cell 0.1 μm Hydrophilic region Hydrophobic region Hydrophilic region Phospholipid Proteins Carbohydrate side chain double layer of phospholipids.
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1/14/2010 3 Surface area increases while total volume remains constant 5 1 1 Surface area and volume The logistics of carrying out cellular metabolism sets limits on the size of cells. As the surface area increases by a factor of n 2 , the volume increases 6 150 750 125 125 1 6 6 1.2 Total surface area [Sum of the surface areas (height × width) of all boxes sides × number of boxes] Total volume [height × width × length × number of boxes] Surface-to-volume (S-to-V) ratio [surface area ÷ volume] © 2010: D. Julian by a factor of n 3 . Small cells have a greater surface area relative to volume. ENDOPLASMIC RETICULUM (ER) Smooth ER Rough ER Flagellum Centrosome CYTOSKELETON: Plasma membrane Nuclear envelope Nucleolus Chromatin NUCLEUS Overview of an animal cell Microfilaments Intermediate filaments Microtubules Microvilli Peroxisome Mitochondrion Lysosome Golgi apparatus Ribosomes © 2010: D. Julian NUCLEUS Nuclear envelope Nucleolus Chromatin Rough endoplasmic reticulum Smooth endoplasmic reticulum Ribosomes Central vacuole Golgi apparatus Overview of a plant cell Microfilaments Intermediate filaments Microtubules
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This note was uploaded on 01/31/2011 for the course BSC 2010 taught by Professor Bowes during the Spring '08 term at University of Florida.

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Chapter 6- Cell Structure - 1/14/2010 CellStructure 2010:...

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