Plant Structures T6 Flashcards
What happens during photosynthesis?
Photosynthetic organisms such as green plants and algae use energy from the sun to make glucose
What is biomass?
The mass of living material
What is the chemical reaction for photosynthesis?
Carbon dioxide + water =(light)= glucose + oxygen
What kind of reaction is photosynthesis?
Photosynthesis is an endothermic reaction, energy is taken in
What 3 factors affect the rate of photosynthesis?
Light intensity, concentration of CO2, and the temperature
How can you measure the rate of photosynthesis?
Use pondweed and measure the rate of oxygen that comes out, the more oxygen means that there is a higher rate of photosythesis
What happens with photosynthesis when light intensity increases
The rate of photosynthesis will steadily increase until a certain point, beyond that it wont make any difference.
What happens when carbon dioxide levels decrease?
CO2 is one of the raw materials needed for photosynthesis. If there is too little CO2 then the rate of photosynthesis will slow.
What do root hair cells do and how do they complete this job efficiently?
The cells on the surface of plant roots grow into ‘hairs’, which stick out into the soil. Each branch of root will be covered in millions of hairs, which have a larger surface area so they will absorb more minerals and water
What do phloem tubes do?
Phloem tubes transport food. They are made of elongated living cells with small pores in the end walls to allow stuff to flow through it. They transport food substances made in the leaves to the rest of the plant
What do xylem tubes do?
Xylem tubes take water up. They are made of dead cells joined end to end with no cell walls between the and a hole down the middle . They only carry water and mineral ions
What is transpiration?
The loss of water from a plant
How does transpiration occur?
Transpiration is caused by the evaporation and diffusion of water from a plant’s surface. Most transpiration happens at the leaves.
What are stomata?
Stomata are tiny pores on the surface of a plant. They are mostly found on the lower surface of the leaves. Stomata allow CO2 and oxygen to diffuse directly in and out of a leaf. They also allow water vapour to escape during transpiration
What 3 factors increase transpiration rates?
Light intensity, temperature, and air flow
What piece of apparatus measures transpiration?
Potometer
Features of a leaf?
Leaves are broad, so there’s a large surface area exposed to light, which is needed for photosynthesis.
What is the palisade layer?
The palisade layer has lots of chloroplasts. This means that they’re near the top if the leaf where they can get the most light
What is the upper epidermis?
The upper epidermis is transparent so that light can pass through to the palisade layer.
How are plants with small leaves adapted to their environment?
Plants with small leaves reduce surface area for water loss by evaporation. Spines also help stop animals eating the plant
What are auxins?
Auxins are plant hormones which control growth at the tips of shoots and roots
What are phototropic?
Shoots are positively phototropic (grow toward light) and roots are negatively phototropic (grow away from light)
What are gravitropic?
Shoots are negatively gravitropic (grow away from gravity) and roots are positively gravitropic (grow toward gravity)
How can plant hormones be used commerically?
As selective weedkillers Growing from cuttings with root powder Controlling flower and fruit formation Producing seedless fruit Controlling the ripening of fruit Controlling seed germination
