Plant cells Flashcards
List all features of plant cells
-chloroplasts
-tonoplast
-cell wall
-middle lamella
-amyloplast
-pits
-plasmodesmata
-vacuole
everything about chloroplasts
-site of photosynthesis
-contains stacks of thylakoid membranes which contain chlorophyll
-this is called grana/granum
-Each coin is a thylakoid
-Each thylakoid has an outer membrane called thylakoid membrane
-lamellae-grana connected by thylakoid membranes
-Grana are surrounded by a colourless fluid called stroma(contains all enzymes required for photosynthesis)
-chloroplasts are bound by a double membrane called envelope
vacuole
-contains cell sap
-is surrounded by a single membrane called tonoplast
-role is for strength and support
middle lamella
-in between cells
-acts as a cementing layer between the primary walls of adjacent cells
amyloplasts
contains amylopectin(starch)
has a double membrane
pits
where there is a break in the cell wall but membrane is still intact(used for communication between adjacent cells)
plasmodesmata
cytoplasm between the cell walls of adjacent cells involved in transport of substances
cell wall
made of cellulose
structure of cellulose(in cell wall)
-straight cellulose chains- due to 1,4-glycosidic bonds
-is a polysaccharide- made up of glucose units
-H bonds between beta glucose molecules cause microfibrils to form
-microfibrils are bundles of cellulose chains/helical structure w/ polysaccharide glue
polysaccharide glue in cellulose
-pectin(acts as cement) and hemicelluloses
-short branched polysaccharides
-binds to surface of cellulose and each other, holding microfibrils together
what are primary cell walls
-formed as cells are growing
-fibrils are parallel(in one direction)
-makes cell wall flexible
what are secondary cell walls
-forms when cells are grown
-microfibrils are laid in all directions
-makes cell wall more rigid
what are the 3 types of saccharides
mono,di,poly
monosaccharides join together to form disaccharides and polysaccharides by glycosidic bonds which are formed in condensation reactions
what are xylem vessels
-transports water and minerals from the root of plants to leaves
-structural support
-made of dead tissue with open ends
-thickened with a tough substance called lignin
what are phloem vessels
-the movement of food substances and nutrients from leaves to all parts of the plant
-made of living cells
-translocation
what are the 3 types of ground tissue
collenchyma cells, parenchyma cells, sclerenchyma cells
what are collenchyma cells
thick cell walls w/ extra cellulose
strong
found just below the epidermis
hexagonal shape
what are parenchyma cells
acts as packing between other cells and tissues for protection
also stores food
what are sclerenchyma cells
hat/semi circle shape
found around the vascular bundles of older stems
what are sclerenchyma fibres
-provides structural support
-cell walls are thickened with lignin
-made of dead cells with a hollow lumen and end walls
how are plant fibres(like sclerenchyma fibres)useful for humans?
-sustainable and renewable resource(plants can be regrown)
-biodegradable(can be broken down by microbes)
-plant fibres are very strong(can make ropes)
