B6 - Plant structures and their functions
Photosynthesis
Plants and algae make use of the suns energy to make food. Photosynthetic organisms are main producers of food and therefor biomass
the plant manufactures glucose from carbon dioxide and water using energy transferred from environment to chloroplast by light
Photosynthesis is an endothermic reaction because it needs an input of energy from the environment
the word equation for photosynthesis
carbon dioxide + water ---glucose + oxygen
Part 2 - Plant tissues
carbon dioxide is one of the reactants needed for plants tomake glucose. The rate of photosynthesis will increase when a plant is given higher concentrations of carbon dioxide up to a point
limiting factors for photosynthesis
Light intensity, temperature chlorophyll
temperature affects rate of reactions including photosynthesis
As environment warms up chemical reactions speed up
Photosynthesis is an enzyme controlled reaction
if the temperature increases too much enzymes will denature and rate of reaction will decrease
amount of light also influences photosynthesis
plants in areas of low light don't tend to grow as tall Light intensity decreases as distance between plant and light source increases
as light intensity increases so does rate of photosynthesis up to a point
water plants produce bubbles of oxygen when they photosynthesise, the bubbles can be counted overtime to calculate rate of photosynthesis
light is a limiting factor for photosynthesis when the light intensity is very low but having a too high light intensity may also affect the rate of reaction
this may be caused by saturation of the active sites in enxymes catalysing the reactions and bleaching of chlorophyll
light iintensity equation = 1/distance ^2
if sunlight shines onto water and carbon dioxide a reaction will not occur, the energy must be transferred from the environment to the chlorophyll by light
this energy is used to convert carbon dioxide and water into glucose and oxygen. Chlorophyll is essential for photosynthesis
if there is a reduction in the amount of chlorophyll in a plant then the amount of glucose made by photosynthesis will reduce , the plant will not grow as well
Like animals , plants are organised into tissues made up of similar cells that carry out a particular function.
adaptations of the root
The root surface is covered in millions of root hair cells
root hair cells increase the surface area
present on the mature parts of the root
absorb water and mineral ions from the soil
no chloroplast as they are found in the soil
active transport move substances from a more dilute solution to a more concentrated solution. The energy is provided through respiration