B6 - Plant nutrition Flashcards
Photosynthesis
Process by which plants synthesise carbohydrates from raw materials using energy from light
chlorophyll
green pigment that is found in chloroplasts
word equation for photosynthesis
carbon dioxide + water –> glucose + oxygen
balanced symbol equation for photosynthesis?
6CO2 + 6H2O –> C6H12O6 + 6O2
what does chlorophyll do?
transfers energy from light into energy in chemicals for the synthesis of carbohydrates
What 5 carbohydrates are made in photosynthesis? what are their uses?
starch - energy store
cellulose - build cell walls
glucose - respiration to provide energy
sucrose - transport in the phloem
nectar - attract insects for pollination
why is nitrate ions important?
it makes amino acids & proteins
why is magnesium ions important
it makes chlorophyll (for photosynthesis)
what are the 3 factors needed for photosynthesis?
chlorophyll, light, carbon dioxide
what 3 factors effect the rate of photosynthesis?
-light intensity
-carbon dioxide concentration
-temperature
what 2 features are adaptations for photosynthesis? how do they help?
large surface area - absorb lots of sunlight
thin - gases don’t have to travel far (diffusion distance small)
function of waxy cuticle?
-waterproofs the leaf –> prevents water loss
function of upper epidermis?
-protective layer & barrier to disease organisms
-allows sunlight to penetrate
function of Palisade Mesophyll Layer?
-absorption of light for photosynthesis
function of spongey mesophyll layer (air spaces)?
-allows gas exchange during photosynthesis (carbon dioxide to cells, oxygen from cells)
function of vascular bundle
-delivers water
-carries organic products of photosynthesis (glucose) away
-contains xylem vessels (bring water and minerals to the leaf / support the leaf and stem)
-contains phloem vessels (transports sucrose sugar & amino acids away from the leaf)
function of lower epidermis
-protective layer
-contains stomata / guard cells
function of stomata (guard cells)
-regulate whether the stomata is open or closed
-allows carbon dioxide in
-regulates the loss of water vapour during transpiration
how are chloroplasts adapted for photosynthesis?
contains many chloroplasts
how are cuticles adapted for photosynthesis?
-thicker on upper surface –> more exposed to sunlight
-reduces water loss
how are guard cells and stomatas adapted for photosynthesis?
-less exposed to sunlight –> water doesn’t evaporate much
how are the upper and lower epidermis’ adapted for photosynthesis?
-one cell thick –> less diffusion distance
-transparent –> allows free passage of light
-prevents entry of disease causing organisms (bacteria & fungi)
how is the palisade mesophyll layer adapted for photosynthesis?
-thin
-narrow air spaces
-contains many chloroplasts
-dense packaging
-near leaf surface
——> maximum absorbtion of light energy
-next to airspaces –> chloroplasts can receive carbon dioxide / release oxygen (gas exchange)
-next to vascular bundle –> receive water / send sucrose
how is the spongey mesophyll layer adapted for photosynthesis?
-loosely packed
-covered in a thin layer of water
-air spaces present –> allows gas exchange (water diffuses out)
how are air spaces adapted for photosynthesis?
-aid diffusion of gases
-saturated with water vapour –> water diffuses out of leaf
-allows gas exchange
how are vascular bundles adapted for photosynthesis?
-contains xylem and phloem vessels
producers
make their own food
why doesnt photosythensis happen in the roots?
no light –> no photosynthesis
how does the carbon dioxide get into the leaf?
diffuses into the bottom, into little holes/pores called stomata
is photosynthesis endothermic or exothermic?
endothermic - needs energy to keep it going
what does the plant use glucose for?
respiration and growth
how and where is extra glucose stored?
stored as starch in the leaf
increase biomass using glucose?
growth increases biomass
how does water enter the plant?
roots (root hairs), by osmosis,
where does water come from?
soil
how does water travel to the vessels?
xylem vessel
how are roots adapted to increase water uptake?
root hair cells increase surface area
what does chlorophyll do?
transfers light energy into chemical energy
why do plants make nectar?
to attract insects
why is it important that glucose is stores as staarch in some plants
no sunlight –> can’t photosynthesize –> glucose for respiration at night
deficient in magnesium?
poor growth and yellowish leaves
deficient in nitrates
very ittle growth
how are minerals gotten?
-absorbed from the soil –> using active transport
how are plants adapted to get minerals?
-large surface area –> easier
-root hair cells have many mitochondria –> release energy
what does it mean to destarch a plant?
leave plant in dark for at least 24 hours to get rid of all stored starch
test for need of chlorophyll during photosynthesis
use a variegated leaf and test for starch
test for need of carbon dioxide during photosynthesis
leaf is destarched then air tight bag is put on the leaf and soda lime is added in the bag
test for need of light during photosynthesis
leaf is destarched then a material that light can’t go through is placed on some parts of the leaf (uncovered parts = control) . the leaf is put in light for at least 24 hours.
test a leaf for starch
1) boil in water for 2 mins - stop enzyme action, easier penetration by ethanol, break cell wall
2) leaf is warmed in ethanol until colourless - extract chlorophyll so results are easier to see
3) leaf dipped in warm water briefly - soften the brittle leaf, allow penetration by iodine solution
4) leaf placed on white tile and iodine solution is added - iodine shows presence of starch, white tile has greater contrast in colour=easier to see
why do plants use up their stored starch when placed in the dark?
-no light so plant can’t photosynthesize
-needs glucose for respiration so it uses the stored starch (glucose) for energy
improvement: bubble volume varies
use gas syringe / upturned measuring cylinder
improvement: number of bubbles could be miscounted
film it / have multiple people counting
improvement: lamp could have increased the water temperature
heat sync (tank of water between lamp and plant case to absorb heat)
conclusion structure
as independant variable increases/decreases, dependent variable increases/decreases. This means that as a factor of photosynthesis increases/decreases, the rate of photosynthesis increases/decreases. This is because factor is needed for photosynthesis.
is carbon dioxide acidic or alkaline
acidic
compensation point
when rate of photosynthesis is exactly equal to the rate of respiration - no net uptake or loss of carbon dioxide or oxygen - glucose consumed by respiration is exactly equal to glucose produced during photosynthesis
