Question

Explain the metabolic purpose of the Calvin cycle in 1-2 sentences

Explain the 3 basic steps of the Calvin cycle using the following terms: ADP/ATP, CO2, electrons, 5C precursor/RUBP, NADP+/NADPH, Rubisco, Sugars

Why photorespiration is wasteful? Explain what cycle doesn’t occur, what isn’t made, and what is wasted.

Answer 1

1. The basic purpose of the Calvin cycle is to convert Carbon Dioxide and Water Into Glucose. In the most general sense, the primary function of the Calvin cycle is to make organic products that plants need using the products from the light reactions of photosynthesis (ATP and NADPH).

2.

3 Molecules CO2 RuBisCO Stage 1: carbon fixation 3 ADP 6 ATP 3 ATP Calvin Cycle 6 ADP Stage 3: regeneration of RuBP Stage 2: reduction 6 NADPH 6 NADP++ H+ Sugar

The Calvin cycle has three stages. In stage 1, the enzyme RuBisCO incorporates carbon dioxide into an organic molecule. In stage 2, the organic molecule is reduced. In stage 3, RuBP, the molecule that starts the cycle, is regenerated so that the cycle can continue. Please refer to the diagram.

3. Photorespiration is a wasteful process because it prevents plants from using their ATP and NADPH to synthesize carbohydrates. RuBISCO, the enzyme which fixes carbon dioxide during the Calvin cycle, is also responsible for oxygen fixation during photorespiration.

Carbon dioxide and ammonia are lost during this process. Glucose and ATP are not formed during this process. The cycle for CO2 fixatio doesnot occur in photorespiration.