Topic F: Plant Transport Flashcards
Define Osmosis?
-Movement of water from an area of high water potential to a low water potential down a water potential gradient through a semi-permeable membrane, this requires no energy.
Why is a root hair cell good at doing what it does?
- Increase surface area so a faster rate of diffusion and osmosis.
- Also it can help with stability.
Define Diffusion?
-Movement of particles from a high concentration gradient to low one until equilibrium is reached. This also requires no energy.
Rain helps water enter the roots because?
- Raising the water concentration.
- Raising water potential.
- Water passes through permeable membrane from the soils high water potential to the cells lower water potential .
What is water used for in plants?
- Photosynthesis.
- Keeping the leaves Turgid.
What are present in large numbers to aid active transport, in root hair cell?
-Root hair cell, mitochondria (power).
What carrys water up the stem of the plant?
-Xylem via Osmosis.
Define Active Transport
-The movement of particles against the concentrating gradient (low-high) THIS REQUIRES ENERGY.
What carrys water into the leaf?
-The mid rib.
What is the role of the Xylem?
-The Xylem is used to suck water and mineral salts from the roots to the other parts of the plant. This is done by the transpirational pull, caused by water lost in the leaves.
How does water move through the plant?
- Is absorbed from the soil through root hair cells.
- Is transported through the xylem vessels up the stem to the leaves.
- Evaporates from the leaves (transpiration).
What is the use of the Phloem vessel?
-Phloem Vessels are involved in translocation. This is the movement of food substances from the stems to growing tissues and storage tissues.
Describe the structure of the Xylem and the Phloem?
-Xylem vessels consist of dead cells. They have a thick, strengthened cellulose cell wall with a hollow lumen. On the other hand, phloem consists of columns of living cells.
How is water absorbed by root hair cells?
-Water passes into the root hair cell by osmosis, form the higher water concentration in the soil, to the lower water concentration in the vacuole, through a selectively permeable membrane (cell membrane).
Define Transpiration?
-This is the evaporation of water from the leaves of plants. the evaporation actually takes place in the leaf, from the spongy mesophyll cells.
In bright light, what happens to the rate of transpiration?
- In bright light transpiration increases.
- The stomata (openings in the leaf) open wider to allow more carbon dioxide into the leaf for photosynthesis.
Where does transpiration take place?
-Spongy mesophyll cells.
When it is windy, (the air is moving around) what happens to the rate of transpiration?
- Transpiration is faster in windy conditions.
- Water vapour is removed quickly by air movement, speeding up diffusion of more water vapour out of the leaf.
At high temperature, what happens to the rate of transpiration?
- Transpiration is faster in higher temperatures.
- Evaporation and diffusion are faster at higher temperatures.
When there is high humidity, what happens to the rate of transpiration?
- Transpiration is slower in humid conditions.
- Diffusion of water vapour out of the leaf slows down if the leaf is already surrounded by moist air.
Experiments to investigate the role on environmental factors in determining the rate of transpiration from a leafy shoot?
- Cut a leafy shoot from a plant and plunge its base into water (try not to get any water on the leaves). This prevents the xylem from taking up any air.
- Put the stem into a large sink full of water and carefully trim the shoot again, by cutting off the bottom under water with a sharp razor blade. Keep the leaves out of the water.
- Immerse the whole of the potometer into the sink. Move it about until all the air bubbles come out.
- Put the shoot stem into the bung, grease the joint with plenty of petroleum jelly, then put the bung into the potometer.
- Make sure the tap is closed, then lift the whole ensemble out of the water.
- Leave the end of the capillary tube out of the water until an air bubble forms then put the end into a beaker of water.
Transpiration provides plants with water for?
- Cooling.
- Photosynthesis.
- Support.
- Movement of minerals.
To measure transpiration we use a?
-Potomenter.
Potometer experement?
-We measure the movement of a bubble/ unit time so mm/sec We will change environmental conditions and compare. Must only change one!
What is the Xylem wall made of?
lignin
What is the Phloem wall made of?
Cellulose
Direction of flow for Xylem and Phloem?
- Xylem, up the stem, and Phloem, two way flow from source to where it is needed in the leaf.
Word Equation for photosynthesis?
carbon dioxide+water->sunlight-> glucose+oxygen
Explain need for plant transport in large organisms?
- humans larger organisms have smaller SA to Vol ratio
- Diffusion
- Less efficient
- need to move oxygen
- circulatory system.
Female gametes are made in the
ovule
fertilization takes place in the
ovule
embryos develop in the..
seed
What is Phosphorus used for in plants?
DNA, cell membranes, respiration and growth, poor root growth
Will go purple
What are potassium ions used for?
Needed to help respiration and photosynthesis
If insufficient, nitrates and magnesium will turn leaves….
Yellow
What does ADH stand for?
Anti Diuretic hormone
