Plant Nutrition Flashcards
Describe photosynthesis
The process by which plants synthesise carbohydrates from raw materials using energy from light
State the word equation for photosynthesis
carbon dioxide + water → glucose + oxygen
in the presence of light and chlorophyll
What is chlorophyll
A green pigment that is found in chloroplasts
What is the function of chlorophyll
chlorophyll transfers energy from light
into energy in chemicals, for the synthesis of carbohydrates
Outline the subsequent use and storage of the carbohydrates made in photosynthesis
starch as an energy store
cellulose to build cell walls
glucose used in respiration to provide energy
sucrose for transport in the phloem
nectar to attract insects for pollination
Explain the importance of nitrate ions
Making amino acids
Deficiency: small plant due to slow/stunted growth
Explain the importance of magnesium ions
Making chlorophyll
Deficiency: plant lacks chlorophyll, leaves turn yellow
Investigate the need for chlorophyll using
appropriate controls
Take a potted plant with variegated (green and white) leaves.
De-starch the plant by keeping it in complete darkness for about 48 hours.
Expose the plant to 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 the leaf is colourless to extract chlorophyll, which would mask the observation
Dipped into the water briefly: to help soften the leaf
The leaf is placed on a white tile, and iodine is added. If starch is present, the colour will be blue-black; if absent, it will remain brown
Investigate the need for light using
appropriate controls
De-starch the plant by keeping it in darkness for 48 hours
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 blue-black
-ve result = parts which didn’t receive light remains brown
Investigate the need for carbon dioxide using appropriate controls
Take two de-starched potted plants.
Cover both the plants with bell jars and label them A and B.
Inside A, keep (Sodium Bicarbonate). It
produces CO2.
Inside B, keep (Sodium Hydroxide). It absorbs CO2
Keep both 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 brown after the starch test
Define limiting factors
Something present in the environment in
such short supply that it restricts life processes.
What are limiting factors of plants
Light intensity
Water
Carbon dioxide
State the balanced chemical equation for
photosynthesis
6CO2 + 6H2O → C6H12O6 + 6O2
What is the leaf structure of a plant from top to bottom
Waxy cuticle
Upper epidermis
Pallisade mesophyll
Spongy mesophyll
Lower epidermis
Stomata and guard cells
Function of the cuticle
the waxy layer that prevents water loss from the top of the leaf
