5.2 - Ecosystems rely on energy transfer Flashcards
What happens in the light-dependent reactions of photosynthesis?
- chlorophyll absorbs light energy from the Sun
- this energy excites electrons in the PSII chlorophyll
- electrons are passed down the electron carriers which make up the electron transport chain
- energy lost from redox reactions is used to produce ATP
- electrons are passed onto PSI chlorophyll & electron transport chain is continued
- photolysis occurs & produces oxygen, electrons and hydrogen ions
- electrons & H+ ions (from water) join with NADP to form reduced NADP
What is the word equation for photosynthesis?
carbon dioxide + water -> oxygen + glucose
What is the symbol equation for photosynthesis?
CO2 + H2O -> C6H12O6 + O2
Is photosynthesis endo or exothermic?
endothermic
What are the 4 photosynthesis limiting factors?
- temperature
- carbon dioxide concentration
- light intensity
- water availability
What 4 molecules is the glucose from photosynthesis turned into?
starch, amino acids, lipids & cellulose
what is meant by an autotroph?
a self feeding organism
what is a producer?
plants that make their own food by making organic compounds in photosynthesis
What are chemosynthetic autotrophs?
organisms which make organic moleucles from chemical reactions
What is ‘primary productivity’?
the rate at which energy is stored in organic molecules in an ecosystem
What are co-enzymes?
substances which link different enzyme-catalysed reactions into a sequence during metabolic processes
Why do ecosystems rely on producers?
producers are autotrophs, so they trap energy from the sun in the form of biomass. the consumers gain this energy, so without producers the whole ecosystem would collapse
What are the 2 reactions in photosynthesis?
- light-dependent reaction
- light-independent reaction
What happens during the light dependent reaction?
use energy from light & hydrogen from photolysis of water, to produce reduced NADP and ATP
What is the ‘waste product’ in the light dependent reaction?
oxygen
What happens during the light-independent reaction?
uses the reduced NADP and ATP to reduce carbon dioxide to glucose
What is ‘gross primary productivity’? (GPP)
rate at which energy is incorporated into organic material in plants
