Lecture 7-1201

Lecture 7-1201 - Lecture 7 15:11 Cytoskeleton Provides...

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Unformatted text preview: Lecture 7 15:11 Cytoskeleton Provides structure to the cytoplasm Initially cytoplasm (ground substance) was thought to be without structure Fig 6.20 Flagella and Cilia Organelles involved in movement Bacteria have flagella but are constructed differently than in eukaryotes Fig 6.23 Same structural design in flagella and cilia 9+2 structure-only in eukaryotes (absent in higher plants) o Different than the flagella of bacteria Flagella larger and fewer in number than cilia Other elements involved in movement Sliding filaments 9+2 structure Molecular motors Sliding filaments Proteins involved in movement o E.g., actin and myosin Fig 6.27 9+2 Structure The basic design Fig 6.24 Fig 6.25 Molecular Motors Proteins Use ATP Fig 6.21 Centriole In animals (not in higher plants) Similar to the base of a flagellum or cilium Involved in mitosis and meiosis (organizes microtubules) Fig 6.22 UNIT 2 The Problem The interior of a cell is different than its environment How to defend the internal environment but still communicate with the external environment o Transport materials across the barrier Fig 7.2 Fig 7.3 An optimal intermediate fluidity Not too solid Not too fluid Preserves membrane function Do not take fluidity too literally Henrique and Hansen 1900 Raised pigs in hot rooms and dressed them in underwear and then looked at the composition of fat right under their skin Membrane fluidity can acclimate Membrane fluidity adjusted by changing the ratio of unsaturated to saturated fatty acids Fig 5.12 To make a membrane more fluid. What would you add?-Unsaturated fats Saturated fats are solids at room temp Unsaturated fats are oils at room temp Fig 5.13 Fig 7.5 Increase Unsaturated Fats Increases the fluidity of the membrane Functional evidence for the fluidity of membranes Fig 7.6 Fig 7.7 Fig 7.8 Fig 7.9 Fig 7.10 Transport Processes Active o Supplied energy required (ATP) o Moving from low to high o Against concentration gradient o Carrier molecule Fig 7.16 Passive o Down concentration gradient o Moving from high to low o Does not require supplied energy o Diffusion (simple or facilitated) Diffusion Movement of molecules down concentration gradient From regions of high concentration to low concentration regions...
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This note was uploaded on 08/22/2010 for the course BIOL 1201 taught by Professor Wishtichusen during the Spring '07 term at LSU.

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Lecture 7-1201 - Lecture 7 15:11 Cytoskeleton Provides...

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