plant structures Flashcards
what is the word equation for photosynthesis
carbon dioxide+water=glucose+oxygen
what is the balanced chemical equation for photosynthesis
6CO2+6H2O→C6H12O6+6O2.
how does light affect rate of photosynthesis
as the light level increases, rate of photosynthesis also increases. after a certain point , rate of photosynthesis doesnt increase as CO2 or the temperature is a limiting factor
how does CO2 have an affect on the rate of photosynthesis
as CO2 increases, rate of photosynthesis also increses. after a certian point, rate of photosynthesis doesnt increase as light level or the temperature is a limiting factor
how does temperature have an affect on the rate of photosynthesis
increasing temp will increase rate of photosynthesis upto a certain point. after that, enzymes will become denatured
what are some adaptations of root hairs
they have root hair cell which will increase the surface area so it can absorb more water and mineral ions
what are phloem tubes
-tubes made of living cells
-does translocation
-it has end walls
what do phloem tubes mainly transport
sucrose
what are xylem tubes
-made of dead cells
-does transpiration
-it has no end walls
what doe xylem tubes mainly transport
water and mineral ions
what is the process of transpiration
-this is the loss of water from the plant
-the plant loses a small amount of water so more water will then be absorbed
-this water will be absorbed in the roots and will be transported throughout the plant via xylem tubes
what is stomata and why is it used
these are tiny pores on the surface of a plant. they allow CO2 to diffuse in and oxygen to diffuse out of the plant
how does the stomata open
guard cells become swollen with water (turgid) which will open the stomata
how does the stomata close
water in the guard cells will evaporate which means that the guard cells become flaccid.
what is the palisade layer in leaves
this layer has lots of chloroplasts. they are near the top of the leaf so they can get the most light
what is the upper epidermis in the leaves
this is a transparent layer above the palisade layer so the light can pass through it and get absorbed in the palisade layer
what is a waxy cuticle in the leaves
it is a layer at the surface of the leaf and it helps to reduce water loss
what is the spongy mesophyll in the leaves
this contains lots of airspaces which will increase the rate of diffusion of gases
what is the lower epidermis in the leaves
this is found at the bottom of the leaf and it contains lots of stomata
how are plants in the desert adapted
-thick waxy cuticles: to reduce water loss by evaporation
-small leaves or spines: reduces surface area for water loss
-fewer stomatas: reduces water loss
what are auxins
they are plant growth hormones and they control growth at the shoots and roots
how are shoots positively phototrophic
auxins build up in the side which is shade from the son. this makes the cells on the shaded side grow faster so the shoot will then grow towards the light
how are shoots negatively gravitrophic
auxins build up on the lower side of shoot due to gravity. this makes the lower side grow faster, making it grow upwards
how are roots positively gravitrophic
auxins build up in the lower side of the root. but in the roots, more auxins means less growth. so, the top side of the roots grow faster making it grow downwards
how are roots negatively phototrophic
auxins build up on the shaded side of the root. in the roots, more auxins mean less growth. this means the upper half will grow faster making it grow downwards
how do you use plant hormones to produce seedless fruit?
applying gibberellins to unpollinated flowers means that the fruits will grow without seeds
how can plant hormones be used to control seed germination
seeds dont germinate unless they have been through certain conditions. but if they are treated with gibberellins, they can germinate in conditions they normally dont
how can plant hormones be used to control the ripening of fruit
if you add ethene to the fruit, it will ripen on the way to the market
how are plant hormones used to grow plants from cuttings?
if you add rooting powder, which contains auxins, it will grow rapidly.
how are plant hormones used as selective weedkillers
weeds are broadleaved. selective weedkillers have auxins which only affect broad leaved plants
how are plant hormones used to control flower and fruit formation
gibberellins stimulate seed germination. they can be used to make plants flower earlier or in conditions they dont usually flower
