Plant nutrition

Question 1

Photosynthesis

Answer 1

The process by which plants manufacture carbohydrates from raw materials using energy from light

Question 2

Equations for photosynthesis

Answer 2

carbon dioxide + water = oxygen and glucose in presence pf light and chlorophyll
6CO2 + 6H20= 602 + C6H1206

Question 3

What does chlorophyll do

Answer 3

converts light energy to chemical energy needed for the synthesis of carbohydrates

Question 4

Subsequent use and storage of carbohydrate

Answer 4

Glucose used for respiration and after photosynthesis glucose immediately change to sucrose where it is transported and stored as starch

Question 5

Chlorophyll is necessary

Answer 5

 Take a potted plant with variegated (green and white)
leaves.
 Destarch the plant by keeping it in complete darkness for about 48 hours.
 Expose the plant to the sunlight for a few days.
 Leaf boiled in water for 2 minutes to break down cell
walls, denature enzymes and allow for easier
penetration by ethanol. Warmed in ethanol until leaf is colourless to extract chlorophyll, which would mask observation
 Dipped in water briefly: to soften leaf
 Leaf is placed on a white tile and iodine is added. If
starch is present, colour will be blue-black and if absent,
it will remain orange

Question 6

Light is necessary

Answer 6

 Destarch the plant by keeping it in darkness for 48hrs
 Place a stencil over part of a leaf
 Place the leaf in sunlight for 4-6 hours
 Remove the stencil and test for starch
 +ve result = parts which received light turn black
 -ve result = parts which didn’t receive light remain yellow/brown

Question 7

Carbon dioxide is necessary

Answer 7

 Take two destarched potted plants.
 Cover both the plants with bell jars and label them as A and B.
 Inside A, keep NaHCO3 (sodium bicarbonate).It produces CO2.
 Inside B, keep NaOH (Sodium hydroxide). It absorbs CO2.
 Keep both the set-ups in the sunlight for at least 6 hours.
 Perform the starch test on both plants.
 The leaves of Plant A will turn black after the starch test
 The leaves of Plant B will remain orange/brown after
starch test