6. Plants as organisms

Question 1

How do you show that light is needed for photosynthesis?

Answer 1

Put 1 plant in light and 1 in dark (at least 24 hours)
Boil leaves in ethanol (removes cuticle and colour)
Rinse leaves in soft water to soften
Add Iodine solution
Leaf in light should turn blue/black

Question 2

How do you show plants photosynthesise by oxygen given off?

Answer 2

Use water planets, collect and count bubbles of gas
Gas relight glowing splint
Change light intensity and see change in bubbles produced

Question 3

Sexual reproduction in plants

Answer 3

Anther produces male gametes in pollen grain
Pollen grain attaches to the stigma
Pollen tube grown down the style into the ovule
The nuclei from the pollen rain migrates in the egg cell fertilising it and the endosperm
The resulting zygote develops into an embryo
Endosperm and female tissues of ovule make the seed
Ovary grows to make the fruit

Question 4

Where is most water lost?

Answer 4

Through the stomata

Question 5

What is transpiration?

Answer 5

The movement of water from the roots through the Xylem to the leaves

Question 6

What is translocation?

Answer 6

When the phloem tissue carries dissolved sugars from the leaves to the rest of the plant

Question 7

What happens if water is being lost too quickly?

Answer 7

Guard cells close the stomata to prevent wilting

Question 8

What is done with the glucose produced from photosynthesis?

Answer 8

Used for respiration
COnverted to starch for storage
Used to produce cellulose (strengthens the cell wall)
Used to produce proteins