Photosynthesis Questions Flashcards
A student set up 6 bottles. Each contained the same number of gel beads containing algae, and the same volume of hydrocarbonate solution.
The indicator is yellow, when carbon dioxide concentration is high, orange-red when it’s the same as normal air, and purple when it is low.
The student placed the bottles at different positions from the lamp.
After two hours, the ones closest were purple, the ones in the middle were red, and the ones at the end were yellow.
Explain the difference in colour between the closest and furthest bottles.
Bottle A has high light intensity so photosynthesis is occuring much faster than respiration. Therefore the concentration of carbon dioxide is very low. Bottle B is too far away from the light to photosynthesise very fast, but it is respiring, so the concentration of carbon dioxide is very high.
Explain why a leaf covered in black paper makes no food.
The black paper stops light from reaching the chlorophyll. Therefore the leaf cannot use light energy to convert carbon dioxide and water in sugar in photosynthesis.
Explain why photosynthesis is an endothermic reaction.
Energy is taken in (endothermic reactions take energy from the surroundings).
Energy in the form of light is transferred to energy in the form of chemical potential energy in sugars.
Explain the role of plants as producers of food.
Plants carry out photosynthesis, which uses energy transferred by light to produce glucose which can be converted into other food substances.
