Photosynthesis Flashcards
What is the chemical energy in sugar available for?
Respiration or the sugar can be converted into other substances, such as starch (storage) and cellulose (structural)
What are limiting factors of photosynthesis?
Carbon dioxide concentration
Light intensity
Temperature
What is photosynthesis?
A series of enzyme controlled reactions that builds up glucose from carbon dioxide and water
What four things are needed for photosynthesis?
Energy from sun
Carbon dioxide absorbed from air
Water absorbed from soil
Chlorophyll in leaves
Where does photosynthesis take place?
In plant cells, inside tiny structures called chloroplasts which are found inside leaf cells
How are tissues that build leaf cells formed?
Plant cells are stacked together.
What do chloroplasts contain?
Chlorophyll
Where in the chloroplast does light reactions take place?
The granum
Where in the chloroplast does carbon fixation take place?
The stroma
Describe the five steps of light reaction
Light energy is captured by chlorophyll
Light energy is converted to chemical energy, which is carried by ATP
Light energy is used to split water into hydrogen and oxygen (photolysis)
ATP and hydrogen pass to the second stage of photosynthesis and are used to make glucose
Oxygen diffuses out of the cell
Describe the two steps of carbon fixation
Carbon dioxide from the air is combined with hydrogen, using energy carried by ATP
The glucose molecule is produced
Why is carbon fixation temperature dependent?
It’s enzyme controlled
How does CO2 reach the chloroplasts?
By diffusion through tiny holes on the underside of leaves
It then diffuses from cell to cell inside the leaf
What are the holes on the underside of leaves called?
Stomata
How does oxygen move through a leaf?
Diffusion, exiting through stomata
