Assignment 4 (5 points) due by the start of class April 30

Study the metabolic chart posted at http://www.sigmaaldrich.com/life-science/metabolomics/learning-center/metabolic-pathways.html and also given to you. List five important major overall aspects or steps of plant biochemical metabolism missing from this chart you would recommend adding to the chart.

Give brief reasons for your recommended additions.

Top 10 of the better answers you gave or I would recommend are:

1. Calvin-Benson Cycle – the regeneration of RuBP is essential to all of biochemistry and cannot occur without all steps of the Calvin-Benson Cycle.

2. Nitrogen Fixation – the reduction of N2 to ammonium is also essential to all biochemistry and life as we know it!

3. Carbonic anhydrases (CA's) - involved in maintaining the supply of CO₂ for Rubisco in the chloroplast or as a cytosolic enzyme catalyzing bicarbonate synthesis to feed the PEP carboxylase.

4. Photorespiration - This C₂ salvage pathway is necessary for plants to handle the oxygenase function of RUBISCO.

5. Cellulose – essential plant molecule that can be simply added. Most abundant polymer on earth (this and other important polymers can be indicated by an arrow and just the word).

6. Starch – not as important as cellulose but also essential and simple.

7. α-linolenic acid – essential ω3 fatty acid for all higher organisms plant and animal.

8. IPP biosynthesis in plastids – essential isoprenoids are made via the plastid MEP pathway in addition to the cytosolic MVA pathway.

9. Ethylene – essential and simple molecule simply made from common metabolites.

10. Lignin – steps toward lignin including monolignols, essential very abundant polymer.