BIO1140 Study Group #4 Answer Key

BIO1140 Study Group #4 Answer Key - BIO1140 Study Group #4...

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BIO1140 Study Group #4 Answer Key 1. What is the purpose of the plant cell wall and what are the three classes of molecules that are found within it? Purpose: Provides rigidity and protection, regulates permeability Structure involves 3 classes of molecules Structural Fbres – cellulose microFbrils Matrix – polysaccharides (e.g. hemicellulose, pectins) Adhesive molecules – pectins 2. What is the difference between primary and secondary plant cell walls? Primary vs secondary cell wall Middle lamella (pectins) Primary cell wall – loose network of cellulose Fbrils Secondary cell wall – cellulose Fbrils highly organized Multi-layered Lignin 3. There are three main types of methods for cell-to-cell communication in animal cells. What are they called? Adhesive (anchoring) junctions: adherens junction, desmosome Tight junctions Gap junctions 2° wall 1° wall Middle lamella Multilayered 2° wall 1° wall Plasma membrane
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4. Describe the structure of an adhesive junction, and draw a picture. Adhesive (anchoring) junctions Adherens junctions Connect to MFs Small areas or continuous zones of attachment in epithelia Desmosomes Connect to IFs Protein plaque for strong adhesion (skin, cardiac muscle, cervix of uterus) Cadherins Transmembrane glycoprotein Repeats in extracellular domain “zip” together Cell-cell separation ~30 nm Intracellular linking proteins Two types of cell matrix junction Tight junction cadherins Linking proteins MFs
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Focal adhesions : bundles of actin Flaments are anchored to β subunits of integrins
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This note was uploaded on 03/30/2012 for the course SCIENCE BIO1140 taught by Professor Fenwick during the Spring '09 term at University of Ottawa.

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BIO1140 Study Group #4 Answer Key - BIO1140 Study Group #4...

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