UNIT 6: PLANT NUTRITION
Photosynthesis: plants manufacture carbohydrates from raw materials using
energy from light
Chlorophyll: a green, light-absorbing pigment found inside chloroplasts in plant
cells
6CO2 + 6H2O -> C6H12O6 + 6O2 + energy light energy -> chemical
energy
Convert to starch and used as an energy store in their chloroplasts
o Glucose is a monosaccharide, soluble in water, reactive -> involve in
unwanted reactions. When it dissolve or lost from the cell, it will increase
concentration and cause damage
o Starch is a polysaccharide, not very soluble and reactive
Conversion into cellulose to make cells walls
Convert to sucrose for transport because it is small, soluble and less reactive
than glucose
Used to make proteins and other organic substances
Necessit Investigation
y
Light Destarch the plant
Place a stencil over part of a leaf and leave in sunlight for few
hours
Remove the stencil and test for starch
CO2 Cover 2 destarched plants with bell jars and leave in sunlight for 6
hours
Inside A, keep NaHCO3 (sodium bicarbonate) to produce CO2
Inside B, keep NaOH (sodium hydroxide) to absorb CO 2
Perform the starch test on both plant
Chlorop Destarch plant (with green, white leaves) and expose to sunlight
hyll for a few days
Boil leaf to break down cell walls, denature enzymes -> ethanol
can get in
Warmed in ethanol until leaf is colourless -> extract chlorophyll
Dipped in water briefly to soften leaf and place on a white tile to
test for starch
Destarching plants
Leave plant in dark room to use up starch
When test for starch, result can be sure that starch is not present at the
beginning of experiment
Cuticle: layer of wax on the epidermis, produced by epidermal cell to stops water
from evaporating
Epidermis: no chloroplasts, protect inner layer of the leaf
Palisade layer: cells arranged like a fence, main region for photosynthesis
Spongy layer: round cells, arranged loosely with large air space, contain less
chloroplast
Photosynthesis: plants manufacture carbohydrates from raw materials using
energy from light
Chlorophyll: a green, light-absorbing pigment found inside chloroplasts in plant
cells
6CO2 + 6H2O -> C6H12O6 + 6O2 + energy light energy -> chemical
energy
Convert to starch and used as an energy store in their chloroplasts
o Glucose is a monosaccharide, soluble in water, reactive -> involve in
unwanted reactions. When it dissolve or lost from the cell, it will increase
concentration and cause damage
o Starch is a polysaccharide, not very soluble and reactive
Conversion into cellulose to make cells walls
Convert to sucrose for transport because it is small, soluble and less reactive
than glucose
Used to make proteins and other organic substances
Necessit Investigation
y
Light Destarch the plant
Place a stencil over part of a leaf and leave in sunlight for few
hours
Remove the stencil and test for starch
CO2 Cover 2 destarched plants with bell jars and leave in sunlight for 6
hours
Inside A, keep NaHCO3 (sodium bicarbonate) to produce CO2
Inside B, keep NaOH (sodium hydroxide) to absorb CO 2
Perform the starch test on both plant
Chlorop Destarch plant (with green, white leaves) and expose to sunlight
hyll for a few days
Boil leaf to break down cell walls, denature enzymes -> ethanol
can get in
Warmed in ethanol until leaf is colourless -> extract chlorophyll
Dipped in water briefly to soften leaf and place on a white tile to
test for starch
Destarching plants
Leave plant in dark room to use up starch
When test for starch, result can be sure that starch is not present at the
beginning of experiment
Cuticle: layer of wax on the epidermis, produced by epidermal cell to stops water
from evaporating
Epidermis: no chloroplasts, protect inner layer of the leaf
Palisade layer: cells arranged like a fence, main region for photosynthesis
Spongy layer: round cells, arranged loosely with large air space, contain less
chloroplast
