plants

Question 1

What is the word equation for photosynthesis?

Answer 1

Carbon dioxide +water ➯ glucose + oxygen

Question 2

What is the chemical equation for photosynthesis?

Answer 2

6CO2 + 6H2O ➯ C6H12O6 + 6O2

Question 3

How do you test the requirement for light?

Answer 3

• cover part of the leaf w foil or card
• leave another part uncovered
• after being left in sun, test with iodine
• covered section should remain brown, as no sun, so no PS or starch

Question 4

How do you test for the production of starch?

Answer 4

• boil leaf in boiling water to denature enzymes in leaf to kill it
• then, using a water bath, boil leaf in boiling ethanol to remove colour
• wash the leaf
• test leaf with iodine. If starch present, goes from brown to blue/black

Question 5

Why do plants need nitrogen?

Answer 5

• needed for amino acids, which make proteins needed for growth.
• plant growth stunted, and leaves yellow without

Question 6

Why do plants need magnesium?

Answer 6

• needed to make chlorophyll, which is needed for PS

* chlorophyll green ∴ leaves look yellow without it

Question 7

How do water and minerals reach the xylem?

Answer 7

• water from soil taken in via osmosis in root hair cells
• minerals taken in via active transport in root hair cells, as there are minerals inside the cells, so energy is needed to bring them against the concentration gradient
• water and minerals diffuse to xylem

Question 8

How does water get from the roots to the leaves?

Answer 8

Through the xylem, which uses capillary action.

Question 9

What is transpiration?

Answer 9

Evaporation of water through the stomata

Question 10

How is the leaf adapted for photosynthesis?

Answer 10

• palisade cells have many chloroplasts and are tightly packed, as chlorophyll needed (generally called mesophyll tissue)
• xylem delivers water, as it is needed
• lower epidermis has stomata to allow gas exchange, for CO2 and O2
• phloem transports glucose produced, as sucrose, around plant
leafs are thin so gasses only have to travel a short distance
upper epidermis allow light pass through them
have large surface area