Plant nutrition/Transport In Plants

desc the function of chlorophyll

absorbs/traps light;

converts light energy into chemical energy;

for synthesis of glucose/carbohydrates

Outline the subsequent use and storage of the carbohydrates made in photosynthesis

glucose used in respiration to release energy/as energy store;

converted to/stored as starch;

converted to sucrose for translocation/transport in phloem;

used in nectar to attract pollinators;

in fruits to attract animals;

converted to cellulose for cell walls;

lignin for cell walls;

used to make amino acids/fatty acids

explain how a leaves features are adaptations for photosynthesis

large surface area to absorb more light;

thin to allow fast diffusion/gas exchange throughout leaf;

air spaces connect to outside via stomata for carbon dioxide storage and gas exchange

Explain how leaf structures adapt leaves for photosynthesis

upper epidermis transparent/thin to let light through;

palisade cells with many chloroplasts/chlorophyll to absorb light;

palisade cells arranged lengthways so fewer cell walls scatter light;

palisade cells packed close together;

spongy mesophyll air spaces allow CO2 diffusion;

guard cells/stomata allow CO2 into leaf;

xylem provides water;

phloem removes products

How temperature has an effect on rate of photosynthesis

involves enzymes;

higher temperature increases rate by increasing kinetic energy;

increases effective collisions;

reaction has an optimum temperature;

high temperature denatures enzymes;

increases diffusion rate of CO2

role of Carbon Dioxide in photosynthesis

diffuses down concentration gradient through stomata into intercellular air spaces;

enters palisade mesophyll cell/chloroplast;

reacts with water to form glucose

def Limiting factors

something present in the environment in such short supply that it restricts life processes

Adaptations of xylem

no cell content/hollow for free passage of water; thick lignified cell wall supports plant; no crosswalls creates continuous tube

Desc. transpirational pull

water evaporates from mesophyll into air spaces and diffuses out through stomata;

decreases water potential of mesophyll cells;

water moves from xylem into mesophyll by osmosis down gradient;

pulls water up xylem in continuous column aided by cohesion and adhesion

Relate the structure of xylem vessels to their function

thick strong wall withstands tension/collapse;

lignin in walls is impermeable and waterproof;

wide to transport large volumes;

dead hollow cells offer no resistance to flow;

no cross walls creates continuous column

Explain the effects of temperature on the rate of transpiration

higher temperature increases water loss rate;

evaporation from mesophyll increases with higher kinetic energy;

faster diffusion through stomata

Explain why some parts of a plant may act as a source and a sink at different times

during growing season substances move down to roots or up to growing points/fruits;

when not photosynthesising substances transport upward from storage organs/roots for respiration