Concept explainers
(a)
Interpretation:
If life were to exist elsewhere in the universe, it would require some process like photosynthesis.
Concept introduction:
The plants use the sun’s light energy to convert water and carbon dioxide to form energy-rich glucose molecules by the process of photosynthesis. Photosynthesis occurs in the chloroplasts of plants. Animals being heterotrophic consume plants or other animals for energy requirements.
(b)
Interpretation:
If the Starship Enterprise were to land on a distant planet and find no measurable oxygen in the atmosphere, could the crew conclude that photosynthesis is taking place or not.
Concept introduction:
Water acts as the electron donorin photosynthesis to produce glucose and oxygen. The absence of water hampers the process.

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Chapter 19 Solutions
BIOCHEMISTRY
- Which features of the curves in Figure 30-2 indicates that the enzyme is not consumed in the overall reaction? ES is lower in energy that E + S and EP is lower in energy than E + P. What does this tell you about the stability of ES versus E + S and EP versus E + P.arrow_forwardLooking at the figure 30-5 what intermolecular forces are present between the substrate and the enzyme and the substrate and cofactors.arrow_forwardprovide short answers to the followings Urgent!arrow_forward
- Pyruvate is accepted into the TCA cycle by a “feeder” reaction using the pyruvatedehydrogenase complex, resulting in acetyl-CoA and CO2. Provide a full mechanismfor this reaction utilizing the TPP cofactor. Include the roles of all cofactors.arrow_forwardB- Vitamins are converted readily into important metabolic cofactors. Deficiency inany one of them has serious side effects. a. The disease beriberi results from a vitamin B 1 (Thiamine) deficiency and ischaracterized by cardiac and neurological symptoms. One key diagnostic forthis disease is an increased level of pyruvate and α-ketoglutarate in thebloodstream. How does this vitamin deficiency lead to increased serumlevels of these factors? b. What would you expect the effect on the TCA intermediates for a patientsuffering from vitamin B 5 deficiency? c. What would you expect the effect on the TCA intermediates for a patientsuffering from vitamin B 2 /B 3 deficiency?arrow_forwardDraw the Krebs Cycle and show the entry points for the amino acids Alanine,Glutamic Acid, Asparagine, and Valine into the Krebs Cycle - (Draw the Mechanism). How many rounds of Krebs will be required to waste all Carbons of Glutamic Acidas CO2?arrow_forward
- Sodium fluoroacetate (FCH 2CO2Na) is a very toxic molecule that is used as rodentpoison. It is converted enzymatically to fluoroacetyl-CoA and is utilized by citratesynthase to generate (2R,3S)-fluorocitrate. The release of this product is a potentinhibitor of the next enzyme in the TCA cycle. Show the mechanism for theproduction of fluorocitrate and explain how this molecule acts as a competitiveinhibitor. Predict the effect on the concentrations of TCA intermediates.arrow_forwardIndicate for the reactions below which type of enzyme and cofactor(s) (if any) wouldbe required to catalyze each reaction shown. 1) Fru-6-P + Ery-4-P <--> GAP + Sed-7-P2) Fru-6-P + Pi <--> Fru-1,6-BP + H2O3) GTP + ADP <--> GDP + ATP4) Sed-7-P + GAP <--> Rib-5-P + Xyl-5-P5) Oxaloacetate + GTP ---> PEP + GDP + CO 26) DHAP + Ery-4-P <--> Sed-1,7-BP + H 2O7) Pyruvate + ATP + HCO3- ---> Oxaloacetate + ADP + Piarrow_forwardTPP is also utilized in transketolase reactions in the PPP. Give a mechanism for theTPP-dependent reaction between Xylulose-5-phosphate and Ribose-5-Phosphate toyield Glyceraldehyde-3-phosphate and Sedoheptulose-7-Phosphate.arrow_forward
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