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Unformatted text preview: 1 02/06/07 BILD1 - Lecture 8 1 BILD1 The Cell Prof. Lisa M. Boulanger 02/06/07 BILD1 - Lecture 8 2 Feedback! 02/06/07 BILD1 - Lecture 8 3 • Problem Set 3 posted, discussed this week •Midterm 1 KEY posted today • Regrades on exams in non-erasable pen only –Regrade requests must be submitted in writing, on paper by Feb. 15 th –Whole exam will be regraded! 02/06/07 BILD1 - Lecture 8 4 – All cells have plasma membrane, cytosol, chromosomes, ribosomes – prokaryotes ( no nucleus, few / no organelles, smaller) – eukaryotes (nucleus, mitochondria and/or chloroplasts, cytoskeleton, endomembrane system, larger) – Nucleus: DNA, nuclear envelope (double phospholipid bilayer) – Ribosomes: make proteins--free, bound – Mitochondria, chloroplasts: have DNA, produce energy, double phospholipid bilayer – Peroxisomes: add hydroxyl to toxins, make peroxide, convert to water Highlights from previous lecture: 02/06/07 BILD1 - Lecture 8 5 • The endomembrane system includes : – nuclear envelope – endoplasmic reticulum (smooth vs rough) – Golgi apparatus (protein sorting, shipping) – plasma membrane – Lysosome (phagocytosis, autophagy) – vacuoles (food, contractile, central) • The cytoskeleton affects support, motility, function – Microtubules (tubulin): cilia and flagella – Microfilaments (actin): microvilli, amoeboid movement, cytoplasmic streaming – Intermediate filaments (keratin) 02/06/07 BILD1 - Lecture 8 6 THIS LECTURE: The plasma membrane: • What’s in it, • What can cross it, and • How! 2 02/06/07 BILD1 - Lecture 8 7 Cell Walls of Plants Extracellular components and connections between cells help coordinate cellular activities • The cell wall – Is an extracellular structure of plant cells that distinguishes them from animal cells 02/06/07 BILD1 - Lecture 8 8 • Plant cell walls – Are made of cellulose fibers embedded in other polysaccharides and protein – May have multiple layers Central vacuole of cel Plasma membrane Secondary cel wal Primary cel wal Middle lamel a 1 μm Central vacuole of cel Central vacuole Cytosol Plasma membrane Plant cell walls Plasmodesmata 02/06/07 BILD1 - Lecture 8 9 The Extracellular Matrix (ECM) of Animal Cells • Animal cells – Lack cell walls – Are covered by an elaborate matrix, the ECM • Functions of the ECM include – Support – Adhesion – Movement – Regulation 02/06/07 BILD1 - Lecture 8 10 • The ECM – Is made up of glycoproteins and other macromolecules Col agen Fibronectin Plasma membrane EXTRACELLULAR FLUID Micro- filaments CYTOPLASM Integrins Polysaccharide molecule Carbo- hydrates Proteoglycan molecule Core protein Integrin A proteoglycan complex 02/06/07 BILD1 - Lecture 8 11 Plants: Plasmodesmata • Plasmodesmata – Are channels that perforate plant cell walls Interior of cell Interior of cell 0.5 μm Plasmodesmata Plasma membranes Cell walls Intercellular Junctions 02/06/07 BILD1 - Lecture 8 12 Tight junctions prevent fluid from moving across a layer of cel s...
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- Spring '08
- gap junctions