Topic 4 - Specific organelles of the plant cell Flashcards
Plant specifications
- Cell wall
- Non-living cells are part of the body
- Tiny connections between cells (plasmodesmata) - all cells interconnected
- Plastids
- Vacuoles
- Inclusions
Cell size
Micrometer (bacteria) ↓ Millimeter (nettle hair) ↓ centimeter (hemp fibers)
Cellular compartments
Surrounded with a double phospholipid membrane, differences in function, interaction
Cell membranes
Function: separation and transport
Double phospholipid layer
Unit membrane hypothesis → fluid mosaic membrane
Plasma membrane (plasmalemma), tonoplast (vacuoles)
Function of membrane proteins
Receptor proteins Channel proteins Carrier protein Transport proteins Filaments of cytoskeleton pH regulation (vacuoles) Excretion (dictyosome)
The cytoplasm
Cytosol and cytoskeleton
Cytosol
o Soluble proteins o RNA o Water o Ions o Caarbohydrates o Fatty acids
Cytoskeleton
Spiral protein filaments
Mechanical resistance, migration of cell organelles
Play role in cell
Plant specific organelles
The vacuole system Plastids The cell wall Incrustations Adcrustations Plasmodesmata
The vacuole system
A Chamber bounded with tonoplast membrane storing solid or fluid compounds and gases
Minor importance in animal cells
Provacuole
Vesicles or ER and dictyosomes
Central vacuole
Three provacuoles fused into a larger one
Major functions of the vacuole system
Storage (isolating materials) Cell lysis Maintaining hydrostatic pressure (tugor) and pH Dispersal Protection
Types of vacuoles
Lysosomes
Vegetative (storage) vacuoles
Inclusions
Crystals
Lysosomes (vacuole)
Thick membrane
Hyrdolytic enzymes in the middle - autophage
Vegetative (storage) vacuoles
Diluted water solution, mildly acidic pH 5-6
Ions (e.g. high salt habitats)
By-products (important products for plant life: essenctial oils, paints, flavours)
Waste products (e.g.: glycosides, alkaloids)
Nutrient storage (protein, carbohydrates)
Inclusions
o Non constant, but not essential substances
o No metabolic activity, no membranes
o Protein inclusions: in pulse grains or aleurone layer, globoid or chrystalloid forms homogeneous/heterogeneous
o Carbohydrate inclusions: mainly starch
o Oil inclusions: small droplets of oil in the cytoplasm