topic 6: plant structures and their functions Flashcards
what are the 4 limiting factors of photosynthesis
carbon dioxide levels
light intensity
temperature
amount of plant chlorophyll
equipment needed for core practical topic 6
.ruler
.light source
.sodium hydrogen carbonate solution (carbon dioxide for photosynthesis)
.pondweed (cut end at the top)
.funnel and measuring cylinder with water to measure oxygen volume
relationship between the mean number of bubbles per minute and the distance from the light source
inverse-square law
.doubling the distance cause light to fall by four times
what increase the rate of transpiration
.higher temperatures
.dryer conditions
.windier conditions
.light intensity (increases rate of photosynthesis)
How do green houses help to increase crop yield
Farmers light heat and add extra carbon dioxide into green houses to improve crop yield Cependant
some gardeners use oil burners as these increase heat and carbon dioxide simultaneously
how do the stomata function
.surrounded by two guard cells
.when light intensity is high/ daytime, the guard cells swell and change shape
.this causes stomata to be opened and allow co2 in for photosynthesis by diffusion
.in hot conditions the stomata is closed to reduce loss of water through transpiration
.plant then cannot photosynthesise
explain phototropism with auxins
.auxin if produced at the tip of the plant shoot
.in shoots auxins trigger cells growth/division
.light causes auxins to concentrate on the darker side of the plant shoot
.auxins spread down the shoot so cells grow faster on the darker side
.causes the shoot to grow towards the side with the light
auxins in gravitropism/geotropism
.auxin is produced in the roots
.auxins inhibit cell growth in the plant roots
.gravity causes auxins to concentrate on the lower side of the root
.auxins cause the lower side to grow slower than the upper side
.this causes the roots to grow towards the force of gravity
role of gibberellins in plants (simple)
important in starting the germination of seeds#
role of ethene in plants (easy)
controls cell division and ripening of fruits
uses of auxins
.rooting powder to clone plants
.weedkillers
uses of gibberellins in agriculture
.early germination of plants
.encourage plants to flower
.be used to make fruit grow larger
uses of ethene in agriculture
.trigger fruits to ripen to reduce damaged product during transportation
how to calculate light intensity
light intensity = light/distance squared
features of the xylem
.made of dead cells (so water isn’t used)
.cell walls break down
.lignin to provide extra support
describe the transpiration stream
.water enters into the roots through osmosis
.water moves up the plant through the xylem to leaves
.once the water is used for photosynthesis it exits through pores in the leaf
.this constant need to replenish water leads to the constant stream
why will transpiration happen more when its lighter
more photosynthesis will occur causing more need to replenish water used in reaction
why will transpiration happen more when it is dry
evaporation of water out the leaf cause more water to be delivered to the leaf through the transpiration stream
why will transpiration happen more when windy
wind pushes more water from out the leaves so more water is needed
what do phloem transport
sugars and mineral ions
how is the phloem designed for function
.substances can travel in both directions as all parts of the plant require sugars
.phloem cells are living
.has companion cells with lots of mitochondria to keep the phloem cells alive
.sieve cells allow the sugars to pass through
what process is the phloem involved in
translocation
role of waxy cuticle
physical barrier for plants protection
upper epidermis trait
see through to allow light
role of palisade cells
contains mans chloroplasts for photosynthesis
role of spongy mesophyll
where gases diffuse
role of stomata and guard cells
allow for diffusion of gases into and out of the cell
transpiration of water out of the leaf
explain why potato chips lost mass in salt solution
there is a high concentration of sodium chloride concentration outside the cell than inside
water moves out the potato through osmosis
into the solution
what can plants make out of glucose
cellulose-what the cell wall is made of strengthens the cell structure
what are the 5 uses for glucose in plants
Cellular respiration - break down the glucose to release energy
Make cellulose - which is used to make strong cell walls
Make starch - which is used to store glucose for a later time
Make amino acids - which are used to make proteins
Make lipids - these store the energy as fats or oils for later use
term when the graph levels off when mapping some limiting factors
plateaud
describe changes in rate of photosynthesis due to temperature
Rate initially increases with temperature as particles have more energy and move faster, so react more frequently
Highest rate is at optimum temperature for enzyme
At higher temperatures the rate decreases as bonds holding the enzyme together begin to break, and so the enzyme changes shape
Rate falls to zero as enzymes denature
what do farmers use in greenhouses to climatize and why
paraffin heaters increase temperature and carbon dioxide volume
how do auxins act as weedkillers
Stimulates too much growth
Disrupts growth process and so kills the plant
