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What is the middle lamella?
- Area btwn cells
- Non-living, filled w/ Ca & Mg pectates
- Cement adjacent cells together
- Breakdown of pectin = ripening
What are plasmodesmata?
- Allow continuum of cytoplasm/ mem from one cell to another
What are the 3 main components of the plasmolemma?
- Lipids (40%) -phospholipids, glycoplipids, sterols
- Proteins (40%) - enzs in mem
- Carbs (20%) - linked to proteins/lipids
Why is the plasmolemma structure important?
- Resistance to chilling injury
What phase change happens at critical temperature?
Liquid crystalline state to solid gel phase
What effect does chilling have on plants?
- Changes the physical states of the membrane
- Increases permeability
- Halts mem activities
- Enzs lose ability to catalyze rxns
What determines critical temp?
- Saturation of mem
- Unsat can handle cooler temps
What are some practical implications of chilling resistance?
- Cultural practices (when & where to plant)
- Hardening off
What do the nucleoi do?
Create ribosomal RNA which synth ribosomes
What is the rol of the rough ER?
- Studded with ribosomes
- Protein synth
What is the role of the smooth ER?
- Process/sort proteins
- Synth lipids
- Regulate cytosolic [Ca]
What is the role of dictyosomes (golgi app.)?
- Assemble complex carbs for cell walls
- Synth carb side chains for glycoproteins
- Give rise to vescicles
What are the roles of the vacuoles?
- Digestion - breakdown/recycle almost all cell components
- pH/ionic homeostasis - proton & ion reservoirs
- Defense against paths & herbivores