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Organic Chemistry and Biochemistry Practice
Draw a product, work a curved-arrow mechanism, or practice biochemistry (amino acids, enzymes, metabolism) with instant, misconception-aware feedback. Course maps for CHEM 311, 312, and 405 are under Objectives.
Problems
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Stuck? Reveal the mechanism — you'll still need to work out the product.
For self-paced study — try it yourself first.
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Experimental. The engine still grades; this only asks a question about that verdict. Submit a structure to start.
Rank the molecules
Choose the best answer
Metabolic flux
An illustrative whole-body sketch — not anatomy class. Oxygen and food both enter just outside the mouth, then O₂ goes to the lungs and food to the gut. O₂ and CO₂ travel lungs ↔ muscle along the left side of the torso; they do not enter the liver. Lactate is the ribbon that returns to the liver. Dashed ribbons are active fluxes (short ones included). Hover a line or the matching legend row to highlight it.
Hover a ribbon or organ
Short labels sit on the figure. Hover a line or the matching legend row to highlight it and read what it does.
Oxygen, food, insulin, and fatty acid stay where you set them. Only the liver glycogen store is allowed to change, so later points are “deeper into the bout.” The vertical scale is a toy 0–1 range, not mM or mmol/min. Lactate on this plot is how fast it is being made (same as anaerobic glycolysis), not how much has accumulated in blood.
How to draw arrows
Tap a source, then a sink (or press, drag, and release on a sink) to draw an electron-flow arrow (release outside cancels). Multi-step mechanisms check one step at a time; each new step appears above the previous one, and the products appear at the top when you finish. Click an arrow (or Remove in the list) to delete it; Undo / Clear also work.
Your answer
Tip: use Clean Up (Ctrl+Shift+L) to normalize bond lengths and angles, or Layout (Ctrl+L) to rearrange the structure; both are in the editor toolbar.
SMILES input (or draw above)
Paste or type a SMILES string. If Ketcher is loaded, the Submit button will pull the SMILES from the editor instead.