The mitochondrion and chloroplast work together through a series of energy transformations to enable green plants to thrive.

The reaction C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂0 provides an overall summary of the exergonic release of some 2,870 kJ of energy per mole of glucose oxidised, which, in turn, yields approximately 30 ATP per mole of glucose oxidised (where ATP is the universal energy currency).

a)    Given Cellular Respiration is not 100% efficient and considering the first Law of Thermodynamics: apart from ATP synthesis, explain how else energy is released when glucose is oxidised.                   [2 marks]

Your answer:

b)    Considering a plant cell, discuss this statement: "The mitochondrion is responsible for most but not all the ATP produced for cellular work in this cell."

In your answer, include a very brief description of all the processes that produce this ATP in the cell, and where these processes occur. [5 marks]

Your answer:

c)     Discuss this statement: "Photorespiration is considered by many to be a wasteful process and therefore an evolutionary oversight."

In your answer, state what is meant by photorespiration and describe the biological adaptation (mechanism) CAM (Crassulacean Acid Metabolism) plants have evolved that concentrates carbon and thus enables these plants to minimise photorespiration.  

The mitochondrion and chloroplast work together through a series of energy transformations to enable green plants to thrive.

The reaction C6H12O6 + 6O2 → 6CO2 + 6H20 provides an overall summary of the exergonic release of some 2,870 kJ of energy per mole of glucose oxidised, which, in turn, yields approximately 30 ATP per mole of glucose oxidised (where ATP is the universal energy currency).

a)    Given Cellular Respiration is not 100% efficient and considering the first Law of Thermodynamics: apart from ATP synthesis, explain how else energy is released when glucose is oxidised.                   [2 marks]

• Your answer: Glycolysis is the enzymatic break down of a glucose molecule, producing two pyruvate molecules, and during glycolysis, some of the free energy is released and conserved in the form of ATP and NADH. Also, most of the free energy from the oxidation of glucose, that is available, will remain in the pyruvate, one of the products of glycolysis.

b)    Considering a plant cell, discuss this statement: "The mitochondrion is responsible for most but not all the ATP produced for cellular work in this cell."

In your answer, include a very brief description of all the processes that produce this ATP in the cell, and where these processes occur. [5 marks]

• Your answer: Plant cells contain organelles called chloroplasts. Chloroplasts contain chloroplasts that capture photons. These photons initiate a sequence of chemical reactions that create two types of high energy compounds, known as adenosine triphosphate or ATP and nicotinamide adenine dinucleotide phosphate or NADPH. On the contrary, chloroplasts do not produce ATP. Rather, they are the sites that aid in the formation of the energy, in the form of ATP, which is produced in the mitochondria.

c)     Discuss this statement: "Photorespiration is considered by many to be a wasteful process and therefore an evolutionary oversight."

In your answer, state what is meant by photorespiration and describe the biological adaptation (mechanism) CAM (Crassulacean Acid Metabolism) plants have evolved that concentrates carbon and thus enables these plants to minimise photorespiration.  

• Your answer: Photorespiration, also known as oxidative photosynthetic carbon cycle or C? photosynthesis, is the respiratory process in plant metabolism where the enzyme RuBisCO oxygenates RuBP, thus wasting some of the energy produced by photosynthesis.  In simpler terms, it is the respiratory process in plants that take up oxygen in the light and give out some carbon dioxide, which is different in terms of pattern in general photosynthesis. CAM or Crassulacean Acid Metabolism is the evolved adaptation of plants, especially in the arid areas, which uses the process of carbon fixation pathway. Plants such as the Ananas comosus (pineapple) use biological adaptations of plants such as closing the stomata in the leaves during the day to reduce evapotranspiration and opening the stomata at night to collect CO₂ to allow the gas to diffuse into the mesophyll cells. At night, this gas (CO₂ ) will be stored as a four-carbon acid malic acid in the central vacuole. During the day, the four-carbon malic acid is transported to the chloroplast to be converted again into CO₂, which is used in photosynthesis and is used around an enzyme called the RuBisCO to increase photosynthetic proficiency.