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Plant structures and their functions - Coggle Diagram
Plant structures and their functions
photosynthesis
photosynthesis- there process that plants use to create their own food
equation
factors affecting photosynthesis
light intensity
carbon dioxide concentration
temperature
direct proportion
As the intensity of the light increases, so does the rate of photosynthesis. This is due to the fact that photosynthesis is an endothermic, energy-requiring reaction. More light energy increases the rate at which oxygen is released, resulting in more oxygen bubbles produced per minute.
inverse proportion
Distance and light intensity have an inverse relationship: as distance increases, light intensity decreases. This is due to the fact that as one's distance from a light source increases, light energy spreads over a larger area.
inverse square law
The energy of light is proportional to the square of the distance between the light source and the plant.
At twice the distance away (2d), the light energy is spread over four times the area.
1/d2
The carbon dioxide required for photosynthesis is derived from the atmosphere. It enters the leaves via the stomata. Water enters the plant through the roots and travels through the xylem to the leaves.
plant organisation
Adaptations of the leaf for photosynthesis and gaseous exchange
They have a large surface area for photosynthesis and openings called stomata that allow carbon dioxide into the leaf and oxygen out. Although these design features are beneficial to photosynthesis, they can cause the leaf to lose a significant amount of water. Water can be found on the surface of the cells within the leaf. Some of this water evaporates, allowing water vapour to escape from within the leaf. when that water is evaporated more water is taken in from the roots and that process is called transpiration
To reduce water loss, the leaf has a waxy cuticle that prevents water vapour from escaping through the epidermis. To reduce water loss, leaves typically have fewer stomata on their top surface.
Plants have two different types of 'transport' tissue, xylem(moves water and mineral ions from the roots to the leaves) and phloem(moves food substances). These specialised tissues move substances in and around the plant.
Transport in plants and the structure of specialised plant cells
large vacuole
lots of surface area
lots of mitochondria
root hair cell
stomata
xylem
plant hormones
auxins
in stem they promote growth
in stem auxins make plants grow towards light
in roots they prohibit growth
in roots auxins prevent growth towards the light
uses of plant hormones
gibberellins- used to initiate germination
ethene- used to ripen fruits
questions
Explain the effect of increasing air temperature on the rate of transpiration in a plant. [2 marks]
Because water molecules have more energy and move faster, the rate of transpiration increases.
Explain why the waxy cuticle is important for this pine leaf. [2 marks]
