B6- Plant Structures and Their Functions Flashcards
Translocation
The movement of food substances (mainly sucrose)
Which tissue does translocation take place in a plant?
Phloem tissue
Which strengthening tissue is present in the walls of xylem tubes?
Lignin
What type of transport vessel is made up of dead cells?
Xylem
How are root hair cells adapted for the uptake of water and mineral ions?
Large surface area
What is the role of xylem tubes in a plant?
Carry water and mineral ions from the roots to the stem and the leaves
How does the structure of phloem allow food substances to move between phloem cells?
Pores in the end walls of phloem cells for the food substances to move through
Describe the movement of food substances, via phloem cells, in plants
- food substances move through phloem tubes in both directions
- food substances move from the leaves (where they are made) to the rest of the plant
Explain the constant transpiration stream of water through a plant
- evaporation and diffusion of water from the leaves creates a shortage in the plant
- more water is drawn up from the rest of the plant through the xylem vessels to replace it
- more water to be drawn up from the roots
Suggest how you could vary the light intensity when investigating the rate of photosynthesis
By varying the distance of the lamp from the algae
Explain why you would use a gas syringe when investigating the rate of photosynthesis
To measure the volume of oxygen produced by the algae over a period of time (he can use this to calculate the rate of oxygen production, which corresponds to the rate of photosynthesis
How can you control the CO2 concentration when investigating the rate of photosynthesis
By adding a set amount of sodium hydrogencarbonate to a set volume of water in the flask
Give one factor that you should control when investigating the rate of photosynthesis
Temperature (as it effects the rate of photosynthesis, so it could effect the results)
Give the three environmental factors that can effect the rate of photosynthesis
- light intensity
- temperature
- co2 concentration
What type of reaction is photosynthesis?
Endothermic- energy is transferred from the environment to the plant
What is biomass?
The mass of living material
Word equation for photosynthesis
(light)
carbon dioxide + water —> glucose + oxygen
How does the glucose produced in photosynthesis contribute to a plants biomass?
Glucose is used to make larger, complex molecules that are needed for the plants growth. These molecules make up the biomass of the plant
Explain why photosynthesis organisms are described as the main producers of food for nearly all life
-energy stored in the biomass of photosynthetic organisms is passed along the food chain as animals eat the photosynthetic organisms. These animals are food for other animals. So most of the life on Earth is supported by photosynthetic organisms
Inverse square law:
light intensity ∝ 1/ distance (d)²
What controls the opening and closing of the stomata?
Guard cells (they open stomata when turgid and close stomata when flaccid)
Factors that can affect the rate of transpiration
- light intensity
- temperature
- air flow
Why is the rate of transpiration very low at night time
Photosynthesis can’t happen in the dark, so stomata don’t need to be open to let carbon dioxide inside the leaf. This means stomata begin to close as it gets darker, which reduces the amount of water able to escape from leaves.
How might increasing the temperature in the rooms affect the rate of water uptake in the two plants?
-increasing the temperature would increase the rate of transpiration because the water particles would have more energy to evaporate and diffuse out of the stomata