Question 1
Paper 2Hard16 marksResearchers cultured equal numbers of animal cells with equal supplies of glucose and amino acids, under the same conditions and with oxygen available. For this investigation, enzyme S catalyses condensation reactions that join glucose monomers into glycogen. In a separate test using enzyme S alone, the activity of S was lower when compound X was present.
After 2 hours, mean measurements per culture were:
| Treatment | Glucose removed from medium (mg) | Glycogen accumulated (mg) | Protein accumulated (mg) | CO2 released (mg) |
|---|---|---|---|---|
| Without X | 50 | 18 | 8 | 14 |
| With X | 50 | 6 | 8 | 22 |
CO2 released was recorded as an indicator of respiration.
Define metabolism and explain why many different enzymes are required in cells.
For each reaction, state whether it is anabolic or catabolic.
- Amino acids joined by condensation to form a protein
- Glucose monomers joined by condensation to form glycogen
- Protein hydrolysed into amino acids during digestion
- Glucose oxidized during respiration
A researcher claims that X affects glycogen formation but has no effect on metabolism elsewhere. Evaluate this claim using the enzyme test and all the measurements in the table. State one limitation of the evidence.