paper 2 specification 2

Question 1

how are root hair cells adapted to their function

Answer 1

-hair-like cells on the plant roots. Each root will have millions of root hair cells which add to a large surface area for absorbing mineral ions and water.mineral ions are absorbed by active transport and water is absorbed by osmosis

Question 2

Explain how the structures of the xylem adapted to their function

Answer 2

-tubes made of dead cells strengthened with lignin
-carry water and mineral ions from the roots up to the stem and leaves
-movement of water from roots through the xylem out of the leaves is called the transpiration stream

Question 3

Explain how the structures of the phloem adapted to their function

Answer 3

-made of columns of elongated living cells with small pores to allow stuff to flow through it
-transport food substances to the rest of the plant for immediate use
-this process is called translocation and goes in both directions

Question 4

what is and explain how transpiration is used in the plant

Answer 4

-loss of water from the plant
-caused by evaporation and diffusion
-creates water shortage so more water is brought by the xylem
-more water is drawn up from the roots so there’s a constant transpiration stream
-stream carries mineral ions

Question 5

what is the function of the stomata?

Answer 5

-needed for gas exchange (allowing CO2 and O to diffuse in and out of the leaf)
-allow water vapour to escape in transpiration due to more water being inside the plant through diffusion
-tiny pores

Question 6

what are guard cells

Answer 6

-change shape to control the size of the pore on the stomata.
-when they are turgid (swollen with water)the stomata are open and when the cells are flaccid (low on water and limp) it is closed

Question 7

how does the environment such as light intensity affect the transpiration rate?

Answer 7

-the brighter the light, the greater the transpiration rate. Stomata close once it gets dark-photosynthesis cant to happen in the dark
-when the stomata are closed very little water can escape

Question 8

how does the environment such as temperature affect the transpiration rate?

Answer 8

-the warmer it is the faster the rate of transpiration
-when it’s warm the water particles have more energy to evaporate and diffuse out

Question 9

how does the environment such as airflow affect the transpiration rate?

Answer 9

-stronger wind means better transpiration. If the airflow is poor, the water vapour just surrounds the leaf and doesn’t move away. There is a high concentration of water particles outside the leaf as well as inside so diffusion doesn’t happen as quickly
-if there is good airflow the water vapour is swept away painting a low concentration of water diffusion happens quickly

Question 10

what piece of equipment can be used to measure the rate of transpiration

Answer 10

potometer