photosynthesis/transpiration/plant reproduction Flashcards
how to measure transpiration rates from oil layer experiment?
measure water loss per minute
factors affecting transpiration?
higher temp, light, high wind speed, higher humidity
how does a higher temp affect transpiration
more kinetic energy so molecules move faster
how does light affect transpiration
stomata close when dark so less transpiration can occur
how does increased wind affect transpiration
increases concentration gradient so more diffusion can occur
how does a higher humidity affect transpiration
decreases concentration gradient so diffusion is less likely to occur
why is transpiration important to plants
used as cooling method, prevents wilting by keeping cells turgid, supplies water for photosynthesis
how to use iodine solution to test for photosynthesis
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
what is a safety precaution of this experiment
turn off bunsen as ethanol is flammable, wear goggles to protect eyes
what steps could be taken to show light is needed for photosynthesis
place one leaf in light and one leaf in dark and test for starch production
what steps could be taken to show chlorophyll is needed
use a variegated leaf and draw pattern of chlorophyll to compare results
what steps could be taken to show carbon dioxide is needed
use NaOH to absorb carbon dioxide, test for starch production
3 characteristics of insect pollinated flowers
enclosed stigma
large, brightly coloured petals
shorter filament/enclosed anther
3 characteristics of wind pollinated flowers
feathery stigma
small, dull petals
no nectary
seed formation
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
what is germination
when seed coat splits
explain 3 conditions needed for germination
oxygen- respiration
water- activate enzymes
light- activate plant growth
where are stomata mainly found
the underside of a leaf
role of stomata in transport
creates transpiration stream, water absorbed by roots
role of stomata in gas exchange
oxygen out and carbon dioxide in, allows photosynthesis
how is the upper epidermis adapted for photosynthesis
transparent so lets light through
how is the palisade mesophyll adapted for photosynthesis
they trap light, lots of chloroplasts containing chlorophyll
how is the spongy mesophyll adapted for photosynthesis
air spaces allow for diffusion, xylem transports water
how is the guard cell adapted for photosynthesis
open and closes to let in carbon dioxide
wall of xylem
lignin, thick, dead cells containing no cytoplasm, hollow
what does the xylem transport
water and minerals
why do plants need nitrates
make amino acids and proteins
why do plants need magnesium
make chlorophyll
phloem walls
consists of living cells, made of cellulose
what does the phloem transport
sucrose and amino acids
does the transport of sucrose and amino acids require require energy
yes - translocation
define transpiration
the evaporation of water from the surface of a plant
functions of the transpiration stream
- 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
how to set up a potometer
- set up under water
- cut the stem of a shoot
- put shoot stem into the bung, grease the joint with plenty petroleum jelly
- put the bung into potometer
- make sure tap is closed and lift it out of the water
- leave the end of the capillary tube out of the water until an air bubble forms then put in a beaker of water
what is the point of step 1
prevents any air bubbles from entering the system and blocking xylem
what is the point of step 3
prevents water loss and air entry
how to measure the rate of transpiration from potometer
distance the bubble travels in 5 minutes - take a number of readings and calculate mean rate
