Photosynthesis Flashcards
What did Van Halmont notice in his experiment
What do we know now
Amount of soil at the start and end of growing a tree was equal but tree had increased in weight
Thought that tree’s weight gain had come from the water
(A large amount of mass is from carbon dioxide in the air, together with water turns into carbohydrates through photosynthesis)
What did Joseph Priestly notice in his experiment
What do we know now
Plant placed in a closed vessel with a candle
The candle extinguished very quickly
After 27 days he relit it with a mirror and it burned
We know the plant had produced oxygen
What is the word and symbol equation for photosynthesis
Carbon dioxide+water - glucose+oxygen
6CO2 + 6H2O - C6H12O6 + 6O2
Why do plants convert glucose into starch
Starch can be used immediately to produce energy through respiration.
Some energy is used to build up smaller molecules into larger molecules
Why do plants convert glucose into cellulose
Cellulose is needed to for cell walls
Long chains are cross linked to form a meshwork
Why do plants convert glucose, nitrates and other nutrients into amino acids, then subsequently, proteins
Plants need protein for growth and repair and to make enzymes
What would happen if cells stored soluble glucose
Inside of cell would become very concentrated
Water would constantly move in, making cell swell
Also the carbohydrates would move away in solution from storage areas
How and why is a lipid structure made by plants
Glucose (made by photosynthesis) is converted into lipids (fats and oils)
To store in seeds
Why does plant growth slow down in winter
Lack of sunlight and warmth
How would rate of photosynthesis be increased
What are limiting factors
Higher temperature with heaters
Increased light intensity with lamps
Increased carbon dioxide concentration with fossil fuel heaters or chemicals
What are the two stages of photosynthesis
Light energy splits water releasing oxygen gas and hydrogen ions
Carbon dioxide gas then reacts with the hydrogen ions to make glucose and water
How did scientists discover the source of oxygen in photosynthesis
Plant absorbed water with a higher atomic mass (isotope) and absorbed carbon dioxide as normal.
The heavier oxygen atom was traced and was present in oxygen released from leaves, no evolved oxygen came from the carbon dioxide initially taken in by the plant.
In plants why does respiration never stop but photosynthesis is only in the daytime
Plant needs constant supply of energy, which it releases to stay alive
In the day plants respire constantly but photosynthesise at a greater rate, using the carbon dioxide produced from respiration. At night without light they cannot photosynthesise🌚🌞
Explain light intensity’s effect on photosynthesis
As light intensity increases, so does the rate of photosynthesis (limits the rate)
But it can have no effect if carbon dioxide or temperature become the limiting factor
Explain carbon dioxide concentration’s effect on photosynthesis
As carbon dioxide concentration increases, so does the rate of photosynthesis (limits the rate)
But it can have no effect if light or temperature become the limiting factor
