photosynthesis/transpiration/plant reproduction

Question 1

how to measure transpiration rates from oil layer experiment?

Answer 1

measure water loss per minute

Question 2

factors affecting transpiration?

Answer 2

higher temp, light, high wind speed, higher humidity

Question 3

how does a higher temp affect transpiration

Answer 3

more kinetic energy so molecules move faster

Question 4

how does light affect transpiration

Answer 4

stomata close when dark so less transpiration can occur

Question 5

how does increased wind affect transpiration

Answer 5

increases concentration gradient so more diffusion can occur

Question 6

how does a higher humidity affect transpiration

Answer 6

decreases concentration gradient so diffusion is less likely to occur

Question 7

why is transpiration important to plants

Answer 7

used as cooling method, prevents wilting by keeping cells turgid, supplies water for photosynthesis

Question 8

how to use iodine solution to test for photosynthesis

Answer 8

1) half fill a 250cm cubed beaker with water and boil with bunsen burner
2) using forceps, hold leaf under boiling water for 20 seconds
3) turn bunsen burner off
4) using forceps, push leaf to the bottom of a boiling tube
5) cover leaf in ethanol
6) place boiling tube in the hot water. ethanol will boil
7) once leaf is colourless, remove and wash in cold water for 3 seconds
8) place flat on a white tile
9) cover leaf in dilute iodine solution using a pipette
10) any starch will react with iodine solution

Question 9

what is a safety precaution of this experiment

Answer 9

turn off bunsen as ethanol is flammable, wear goggles to protect eyes

Question 10

what steps could be taken to show light is needed for photosynthesis

Answer 10

place one leaf in light and one leaf in dark and test for starch production

Question 11

what steps could be taken to show chlorophyll is needed

Answer 11

use a variegated leaf and draw pattern of chlorophyll to compare results

Question 12

what steps could be taken to show carbon dioxide is needed

Answer 12

use NaOH to absorb carbon dioxide, test for starch production

Question 13

3 characteristics of insect pollinated flowers

Answer 13

enclosed stigma
large, brightly coloured petals
shorter filament/enclosed anther

Question 14

3 characteristics of wind pollinated flowers

Answer 14

feathery stigma
small, dull petals
no nectary

Question 15

seed formation

Answer 15

1) pollen lands on stigma
2) pollen tube grows down style into the ovary
3) pollen enter via micropyle
4) pollen grain (male gamete) fertilises egg (female gamete)
5) ovule becomes seed, ovule walls become seed walls
6) ovary becomes fruit

Question 16

what is germination

Answer 16

when seed coat splits

Question 17

explain 3 conditions needed for germination

Answer 17

oxygen- respiration
water- activate enzymes
light- activate plant growth

Question 18

where are stomata mainly found

Answer 18

the underside of a leaf

Question 19

role of stomata in transport

Answer 19

creates transpiration stream, water absorbed by roots

Question 20

role of stomata in gas exchange

Answer 20

oxygen out and carbon dioxide in, allows photosynthesis

Question 21

how is the upper epidermis adapted for photosynthesis

Answer 21

transparent so lets light through

Question 22

how is the palisade mesophyll adapted for photosynthesis

Answer 22

they trap light, lots of chloroplasts containing chlorophyll

Question 23

how is the spongy mesophyll adapted for photosynthesis

Answer 23

air spaces allow for diffusion, xylem transports water

Question 24

how is the guard cell adapted for photosynthesis

Answer 24

open and closes to let in carbon dioxide

Question 25

wall of xylem

Answer 25

lignin, thick, dead cells containing no cytoplasm, hollow

Question 26

what does the xylem transport

Answer 26

water and minerals

Question 27

why do plants need nitrates

Answer 27

make amino acids and proteins

Question 28

why do plants need magnesium

Answer 28

make chlorophyll

Question 29

phloem walls

Answer 29

consists of living cells, made of cellulose

Question 30

what does the phloem transport

Answer 30

sucrose and amino acids

Question 31

does the transport of sucrose and amino acids require require energy

Answer 31

yes - translocation

Question 32

define transpiration

Answer 32

the evaporation of water from the surface of a plant

Question 33

functions of the transpiration stream

Answer 33

• to carry mineral ions to the leaves for the synthesis of amino acids and chlorophyll
• to keep turgor pressure high
• evaporation cools leaf
• supplies water for photosynthesis

Question 34

how to set up a potometer

Answer 34

1. set up under water
2. cut the stem of a shoot
3. put shoot stem into the bung, grease the joint with plenty petroleum jelly
4. put the bung into potometer
5. make sure tap is closed and lift it out of the water
6. leave the end of the capillary tube out of the water until an air bubble forms then put in a beaker of water

Question 35

what is the point of step 1

Answer 35

prevents any air bubbles from entering the system and blocking xylem

Question 36

what is the point of step 3

Answer 36

prevents water loss and air entry

Question 37

how to measure the rate of transpiration from potometer

Answer 37

distance the bubble travels in 5 minutes - take a number of readings and calculate mean rate