Resources From Plants Flashcards
What are the organelles in a plant cell?
Cell wall
Middle lamella
Plasmodesmata
Pits
Chloroplast
Amylosplast
Vacuole and tonoplast
What’s the structure and function of cell wall?
Rigid structure surrounding plant cell and made of cellulose
Supports plant cells
What’s the structure and function of middle lamella?
Outermost layer of the cell
Layer acts as an adhesive sticking adjacent plant cells together
Give plant stability
What’s the structure and function of plasmodesmata?
Channels in the cell walls that link adjacent cells together
Allow transport of substances and communication between cells
What’s the structure and function of pits?
Regions of cell wall where it’s very thin and they’re arranged in pairs
Allow transport of substances between cells
What’s the structure and function of chloroplasts?
Small flattened structure surrounded by double membrane and they’re stacked in some parts of chloroplasts to form grana
Site where photosynthesis takes place (some takes part in stroma others takes place in grana)
What’s the structure and function of amyloplast?
Small organelle enclosed by membrane (act as starch granules) and may contain starch granules
Storage of starch grains also convert starch back to glucose for release when plant needs it
What’s the structure and function of the vacuole and tonoplast?
Vacuole is compartment surrounded by membrane called tonoplast
Vacuole contains sap made of water enzymes minerals and water products
Vacuole keeps cell turgid stops plant wilting
Also involved in breaking down unwanted chemicals and tonoplast controls what enters and leaves the vacuole
Key things about the xylem vessel?
Transport water and mineral ions up plant
Provide support
Long tube like structures formed from dead cells joined end to end
Cells longer than they are wide and have hollow lumen and no end walls
Walls are thickened by lignin
Water and minerals move out of vessel through
What’s the function of schlerenchyma fibres?
Provide support and they’re not involved in transport
Key features of the schlerenchyma fibres?
Made of dead cells running vertically up the stem
Cells are longer than they are wide and have hollow lumen but they do have end walls
End walls also thickened with lignin
Have more cellulose
Key features of phloem tissues?
Transport organic solutes (mainly sugars) from where they’re made to where they’re needed - translocation
Formed from cells and arranged in tubes
Contains sieve tube elements and companion cells
Sieve tube elements are joined end to end by sieve tubes
Sieves part of end walls have lots of holes to allow solutes to pass through
Sieve tube element have no nucleus and thin layer of cytoplasm and few organelles
Companion cells are needed so sieve tube elements can survive
How are both phloem and xylem found?
In vascular bundles
How do you disect plant stems?
Use scalpel to cut cross section do it is thinly as possible
Use tweezers to gently place sections in water until you use them (stops them from drying out)
Transfer each section into fish containing stain and leave for 1 minute to allow you to see the position of fibres and vessels
Rinse of sections and place each one on slide
Place slide under microscope and adjust until get a clear image
Structure and function of starch?
Main energy storage in plants
Made of 2 polysaccharides - amylose and amylopectin
Amylose = unbranched chain of ã glucose, angles of glycosidic bonds give jt a coiled structure, makes it compact and so is good for storage
Amylopectin = long branched chain of ã glucose , has side branches allowing enzymes to break down molecule at glycosidic bonds easily (glucose can be released quickly)
What happens to starch when in water?
It’s insoluble so it doesn’t cause water to enter cells by osmosis
Structure and function of cellulose?
Long unbranched chains of ß glucose joined by 1-4 glycosidic bonds
Glycosidic bonds are straight so celluose chains are straight
Cellulose chains are linked together by a number of hydrogen bonds to form strong threads called microfibrils
Strong threads provide structural support
What are plant fibres made from and what are they useful for?
Xylem vessels and schlerenchyma fibres and they’re strong so good as ropes and fabrics
Why are plant fibres strong?
Arrangement if microfibrils in cell wall - net like
Secondary thickening of walls - when some have finished growing they produce another cell wall between wall and membrane, it’s thicker
How do you measure the tensile strength of plant fibres?
Attach fibre to clamp and hang weight from middle
Keep adding weights one by one until it snaps
Record mass needed to break fibre - higher mads is higher tensile strength
Repeat experiment with different samples of same fibre and calculate mean
Fibres should always be same length
Keep temp and humidity constant
Do sustainable practised deplete resources?
No
What is sustainability?
Using resources that meets needs of present generation without messing it up for future generations
What are renewable resources?
Ones that can be used indefinitely without running out e.g. plants
What’s an unsustainable practice?
Ones where the resource will eventually run out e.g. use of fossil fuels to make oil based plastics like polyethene
