Plant nutrition

Question 1

what is the word equation for photosynthesis?

Answer 1

carbon dioxide + water = glucose + oxygen

Question 2

what does the plant convert glucose into?

Answer 2

starch

Question 3

list the ways in which the leaf of a plant is adapted to its function

Answer 3

• broad, flat surface (traps light)
• palisade cells (contain chlorophyll in chloroplasts)
• air spaces allow passage of CO2/O2 via stomata
• veins carry water to cells/glucose to other parts of plant

Question 4

list two features of the lead which are involved in the control of the loss of water

Answer 4

• guard cells

- waxy cuticle

Question 5

list three limiting factors that affect the rate of photosynthesis

Answer 5

• light intensity (higher light = more pho.)
• concentration of CO2
• temperature

Question 6

what is the glucose produced in photosynthesis used for?

Answer 6

• respiration

- transport

Question 7

what does the energy in starch build?

Answer 7

larger molecules such as:

• carbohydrates
• proteins
• lipids

Question 8

what transport systems moved glucose from leaves to the rest of the plant?

Answer 8

• xylem

- phloem

Question 9

what is phloem made from and what does it transport?

Answer 9

living cells

transports sugars

Question 10

how do plants store glucose?

Answer 10

as starch
starch is insoluble so as not to affect how water moves in and out of cells
some plants store starch in tubers and bulbs for winter

Question 11

what are other nutrients plants require?

Answer 11

• minerals
• nitrates
• magnesium

Question 12

why do plants need nitrates and where does they get them?

Answer 12

plants need nitrates for making amino acids which make up proteins
nitrates come from the soil and are taken up by the roots

Question 13

how can you tell if a plant doesn’t have enough nitrates?

Answer 13

it will be short and stunted

Question 14

what do plants need magnesium for and where does it come from?

Answer 14

plants need magnesium for making chlorophyll for photosynthesis
magnesium comes from the soil

Question 15

how can you tell if a plant doesn’t have enough magnesium?

Answer 15

it will look yellow and pale and will not be able to photosynthesise properly

Question 16

what are hydroponics?

Answer 16

an alternative method of growing crops, where plants are grown in water containing nutrients
means plants can be grown quickly and out of season, so fetches better prices

Question 17

how would you test leaves for starch?

Answer 17

• place a leaf in boiling water for 30 seconds to kill it
• heat it in boiling ethanol for a few minutes to remove its colour
• wash with water and spread on a white tile
• drop with iodine solution from a dropping pipette
• the parts of the leaf containing starch will turn blue-black

Question 18

what does an epidermis do?

Answer 18

allows light into the leaf

Question 19

what does spongy mesophyll do?

Answer 19

allows air to move through the leaf

Question 20

what do guard cells do?

Answer 20

open and close to regulate the volume of water within a leaf

Question 21

why do water lilies (which float on water) have guard cells on their upper surfaces rather than lower surfaces?

Answer 21

so water doesn’t flood the leaf and cause it to sink/become flaccid

Question 22

what is the balanced symbol equation for photosynthesis?

Answer 22

6CO2 + 6H2O -> C6H12O6 + 6O2

Question 23

what would you use in an experiment to determine whether or not a plant needs CO2 to photosynthesis?

Answer 23

soda lime, which absorbs CO2