Plants Flashcards
What is phototropism?what is the negative and positive response?
Response to light , positive shoot response , negative root response
What is geotropism and what is the response of the plant ?
Tropism to gravity , positive root response , negative shoot response
What is hydrotropism ? What is positive and negative ?
Response to water , positive root response , no shoot response
What is a tropism?
A directional growth movement made by a part of a stationary plant in response to unilateral stimulus
Why is geotropism important?
The roots find water and mineral salts in the earth , they also stabilise the plant
Experiment for geotropism ?
Grow seeds in different directions and put the seed dish vertical. All of the roots will grow down and shoots will grow up no matter where they are
Clinostat
Importance of phototropism?
Maximises photosynthesis , negative root response orientates plant
Importance of hydrotropism
Locate water for photosynthesis
Which part of the plant is responsible for growth hormones ?how do you know this ?
The tip_coleoptiles
If you remove the coleoptile and put it on another plant , that plant will grow
What happens if the coleoptile is covered ?
The plant wont bend but will grow
What is the hormone released by the coleoptile called ?
Auxin
What does auxin stimulate ?
Growth
Can auxin diffuse through an agar block and still work ?
Yes auxin is water soluble
Learn the mother fucking cross section of a leaf
Okay
If a leaf is growing in a dry environment what adaptations would you expect ?
- waxy surface prevent excess transpiration
- fewer stomata
- smaller leaves
- deep roots
In plants what is nitrate used for ?
Making amino acids and protein
What is magnesium used for in plants?
Chlorophyll production
What are sulphates used for ?
Dna production
structure and adaptation of the waxy cuticle
Thin and waxy layer on too of the leaf , reduces water loss via transpiration
Upper and lower epidermis : structure and adaptation
Relatively transparent and few chloroplasts . Allows light to pass through into the palisade cells
Palisade mesophyll : structure and adaption
Elongated shape contains hundreds of chloroplasts
Spongy mesophyll : structure and adaptations
Loosely packed cells leave air spaces . Allows gasses to diffuse in and out of the mesophyll
Stomata : stricture and adaptations
A gap between guard cells , only on lower epidermis.allows co2 in and o2 and h2o out and can alter shape to open or close
What are the molecules required for photosynthesis ?
Carbon dioxide and water
Do the products of photosynthesis contain more or less energy than the reactants ?
More
Why is glucose stored as starch ?
- takes up less space
- stored more easil
- not water soluble
What do you test for starch with ?
Iodine
what are the factors that affect the rate of photosynthesis ?
- co2 concentration
- light intensity
- temperature
What are the products of photosynthesis ? And where do they go ?
Glucose and oxygen- the glucose is either stored as starch , used to make cellulose , used in respiration
Oxygen is released , used a bit in respiration
What do the graphs of the limiting factors of photosynthesis look like ?
Light intensity - goes up but reaches a plateau
Carbon dioxide - ^^^^^
Temperature- goes up then down
Why is light a limiting factor ?
Even if there is load sof co2 and h2o the plant still will be unable to photosynthesise fast with out light intensity
Why is co2 a limiting factor ?
Carbon dioxide is required compound for photosynthesis … A reactant
Why is temperature a limiting factor ?
To cold and photosynthesis is slow.., to high and enzymes denature
Limiting factors of transpiration ?
Light intensity , humidity , wind , temperature , atmospheric pressure and water supply
How does light affect transpiration ?
Light intensity stimulates the stomatas to open, more photosynthesis and more co2 needed … More transpiration
How does humidity affect transpiration ?
Higher humidity less transpiration … Higher water concentration in air means less diffusion
How does wind affect transpiration rate ?
When there is wind the water vapour is released meaning more transpiration and diffusion takes place going down the concentration gradient
How does temperature affect the rate of transpiration ?
Higher temperature more water evaporates , diffusion faster in higher temps
How does atmospheric pressure affect diffusion ?
Fewer particles around plant more diffuse out
What is the xylem ?
Tissue made up of the cell walls of dead cells . It transports water and dissolved mineral ions up the plant
What is the phloem ?
The phloem tissue is made of living cells . Transports sucrose and amino acids around the plant in
Bother directions
On a cross diagram of a stem .. Where is the xylem
And phloem
Vascular bundles… Xylem inside , phloem outside , pith is the middle , cortex outer
Phloem structure ?
Perforated walls , two way flow , living cell tissue
What is a potometer ?
A device that measure the rate of transpiration
what are the limitations of a potometer ?
Measure water uptake ( some water used in other things )
- cutting the plant shoot may damage the plant
- plant has no roots not realistic
What is a xerophyte ?
Plants that are adapted to live in dry areas
Adaptations of xerophytes ?
- thick waxy cuticle
- hair , traps layer of air , prevent transp
- rolled leaves less surface area available
What is the effect of transpiration?
- it draws water up the stems
- has a cooling effect
A potometer can be used for ?
- measuring water uptake in a plant
- rate of transpiration
- compare rate of transpiration
What is osmosis ?
The movement of water down a concentration gradient through a partially permeable
Membrane
How do you set up a potometer ?
1) cut a leafy shoot underwater
2) insert the leafy shoot
3) fill the potometer with coloured water and fit the stopper
4) seal all of the connections in the aparatus
5) create an air bubble in the tube
6) measure the movement of the water
