Biology Topic 6-Plant Structures and their
Functions
● Plants + algae are main food producers by
synthesising from Sun in Photosynthesis.
● Carbon Dioxide + Water → Glucose + Oxygen
● → = Sunlight
● Photosynthesis is endothermic
● Temperature= When increased, rate of reaction
increases until denatures enzymes
● Light Intensity= Most plants, greater means faster
rate of reaction. Measured in Lux
● Carbon Dioxide Conc= When increased, rate
increases
● Any of above= Limiting Factors
● PONDWEED CORE PRACTICAL
● Light Intensity is directly proportional to Rate of
Photosynthesis
● Light Intensity ∝ 1÷ Distance❑2
● Root Hair Cells-take up water by osmosis and
mineral ions by Active Transport. Large S.A. because
roots so more absorbed; large perm vacuole affects
speed; Mitochondria give energy for respiration
● Xylem Cells- transport from roots up to shoots.
Lignin kills cells, become hollow and join end to end
so water and ions can pass through; lignin
deposited in spirals to strengthen cell and withstand
pressure
● Phloem- Carry products of Photosynthesis all around
the plant, cell walls of each cell form sieve plates so
can pass cell to cell, alive unlike Xylem, energy
supplied by mitochondria of companion cells, use
this energy to transport sucrose.
● Transpiration- loss of water; gaseous exchange and
open stomata; water evaporates at open stomata
Functions
● Plants + algae are main food producers by
synthesising from Sun in Photosynthesis.
● Carbon Dioxide + Water → Glucose + Oxygen
● → = Sunlight
● Photosynthesis is endothermic
● Temperature= When increased, rate of reaction
increases until denatures enzymes
● Light Intensity= Most plants, greater means faster
rate of reaction. Measured in Lux
● Carbon Dioxide Conc= When increased, rate
increases
● Any of above= Limiting Factors
● PONDWEED CORE PRACTICAL
● Light Intensity is directly proportional to Rate of
Photosynthesis
● Light Intensity ∝ 1÷ Distance❑2
● Root Hair Cells-take up water by osmosis and
mineral ions by Active Transport. Large S.A. because
roots so more absorbed; large perm vacuole affects
speed; Mitochondria give energy for respiration
● Xylem Cells- transport from roots up to shoots.
Lignin kills cells, become hollow and join end to end
so water and ions can pass through; lignin
deposited in spirals to strengthen cell and withstand
pressure
● Phloem- Carry products of Photosynthesis all around
the plant, cell walls of each cell form sieve plates so
can pass cell to cell, alive unlike Xylem, energy
supplied by mitochondria of companion cells, use
this energy to transport sucrose.
● Transpiration- loss of water; gaseous exchange and
open stomata; water evaporates at open stomata
