Unit 5 - energy transfers

Question 1

Explain how nitrate may cause the death of fish in fresh water

Answer 1

-algae bloom which blocks light
-no photosynthesis so submerged plants die
-saprobiotic bacteria use oxygen to respire
-so less oxygen for fish to respire
-fish die

Question 2

Explain how crop plants use light energy during the light dependent reaction

Answer 2

-light energy strikes electrons exciting them
-electrons move along electron transfer chain releasing energy
-energy used to join ADP and Pi to form ATP
-photolysis of water produces protons, electrons and oxygen
-NADP reduced by electrons

Question 3

During the light independent reaction of photosynthesis, carbon dioxide is converted into organic substances, describe how

Answer 3

-carbon dioxide combines with RuBP
-produces 2 GP
-GP reduces to 2 triose phosphate
-using reduced NADP
-using energy from ATP
-triose phosphate converted to glucose

Question 4

Describe how ATP is made in the mitochondria

Answer 4

-ATP produced in the kerbs cycle
-link reaction produces reduced coenzymes (NAD AND FAD)
-electrons released from reduced co enzymes
-electrons pass along electron transfer chain
-releasing energy
-protons move into inter membrane space
-ATP synthase forming ATP from ADP and Pi

Question 5

explain how mycorrhizae are beneficial to plants (symbiotic relationship)

Answer 5

-form symbiotic relationships with plants
-the long thin hyphae of the fungi connect with the plant roots
-this increases surface area for water and mineral absorption-the plant can obtain more mineral and water
-the fungi can get useful organic molecules from the plant like sugars