Unit 3: Cell Energetics

Question 1

Describe the process and equation of photosynthesis.

Answer 1

Photosynthesis is the conversion of light energy into chemical energy (glucose) in chloroplasts. 6CO2 + 6H2O → C6H12O6 + 6O2

Question 2

Describe the process and equation of cellular respiration.

Answer 2

Cellular respiration breaks down glucose into ATP, occurring in mitochondria. C 6 H 12 O 6 + 6 O 2 –> 6 CO 2 + 6 H 2 O + ATP

Question 3

What is the relationship between photosynthesis and cellular respiration?

Answer 3

Photosynthesis produces glucose, and cellular respiration uses glucose to produce ATP.

Question 4

How much ATP does cellular respiration generate?

Answer 4

ATP is produced through glycolysis, Krebs Cycle, and Electron Transport Chain. Glycolysis produces a net gain of 2 ATP molecules per glucose molecule. The Krebs cycle generates 1 ATP molecule per turn. The exact number of ATP molecules produced in the electron transport chain can vary, but it is generally estimated that each NADH molecule entering the ETC can yield about 2.5 to 3 ATP, and each FADH2 can yield about 1.5 to 2 ATP. Usually 32 ATP total.

Question 5

Compare cellular respiration to combustion.

Answer 5

Both involve the breakdown of organic matter, but cellular respiration is controlled and produces ATP.

Question 6

How do organisms make energy when no oxygen is available?

Answer 6

Through anaerobic processes like fermentation.