B8-photosynthesis Flashcards
Photosynthesis equation
Carbon dioxide +water-light energy,chlorophyll>glucose+oxygen
6CO2+6H2O->C6H12O6+6O2
Carbon dioxide from where?
diffuses into the leaf through the stomata which allows gases in flanked by 2 guard cells
Water from where
Water enters the roots in the soil and is transported up the leaves by osmosis through specialized plant cells known as xylem vessels and the transpiration stream
Glucose from what
A waste product released back into the air for aerobic respiration
Glucose to build cellulose?
Plants build up glucose into complex carbohydrates such as cellulose to strengthen their cell walls.
Glucose to build starch
Plants convert some glucose into starch to be stored as unlike glucose it doesn’t affect how water moves in and out of the cells and is the main energy source for plants to be used for another time.
Glucose to make amnio acids?
Some Glucose from photosynthesis to make amnio acids which are built up into proteins to be used in the plant cells for many things e.g. enzymes.
Glucose to make lipids?
Some glucose from photosynthesis is used to make lipids which may be used in the cells as an energy store or to make cells walls stronger or an energy store for seeds.
Oxygen for what?
A waste product released back into the air for aerobic respiration
How leaves are adapted for photosythesis
Most leaves are broad giving them a big surface area for light to fall on
Most leaves are thin so diffusion distances for the gases are short
They contain chlorophyll in the chloroplasts to absorb light
They have veins which bring plenty of water in the xylem to the cells of the leaves and remove the products of photosynthesis in the phloem
They have air spaces that allow carbon dioxide to get to the cells and oxygen to leave by diffusion
They have guard cells that open and close the stomata to regulate gas exchange
Light intensity and the inverse square
Light intensity involved the inverse square law. As the distance of the light from the plant increases the light intensity decreases known as an inverse relationship(as one goes up other goes down). Relationship between distance and light intensity is not linear as the light intensity decreases or increases in inverse proportion to the square of the distance so when the light is moved twice as far from the plant it will receive a quarter of the energy.
Key points on making the most of photosynthesis
the factors that limit the rate of photosynthesis interact and any one of them may limit photosynthesis and limiting factors are important in the economics of enhancing the conditions in greenhouses to gain the maximum rate of photosynthesis while still maintaining a profit.
Light intensity is proportional to
(Distance)2
Making the most of photosynthesis the garden greenhouse
Greenhouses glass or plastic building mean the environment is much more controllable than in a garden or field.
The atmosphere is warmer inside than out affecting the rate of photosynthesis with a greater temperature to grow faster and crop better also can help places like UK grow fruit that don’t grow well outside
Making the most of photosynthesis controlling everything
Take advantage of limiting reactions by controlling the temperature, levels of light and carbon dioxide throughout the day using computer software as for example light intensity is lower in the morning. They do this to get the fastest rates of photosynthesis and growth of the plants. Also grown in water with the perfect balance of nutrients instead of soil to make sure nothing slows down the growth also can change mineral content of water as plants get bigger. This is known as hypotonics. This manipulation of the environments using compter software is expensive but turnovers are high meaning profits can be high. Crops are clean and soil free so need to plough or prepare the land and crops can be grown where land is poor.
