Zadanie 1h, Paper 2, listopad 2023, TZ1, Biologia IB HL
Wzorowane na: Biology HL Paper 2, November 2023, TZ1, pytanie 1(h). Treść, dane i kontekst są zmienione; sprawdzane umiejętności, format i punktacja jak w oryginale.
Darmowe konto pozwoli wrócić do niego później.
Zadanie
Polecenie
Informacja do zadań 1 a-1 h.
All values are constructed for a model investigation of mammalian metabolism. At steady state, a circulating metabolite enters the blood at the same rate as it is removed, so its concentration can remain stable despite continuous turnover. Turnover flux is the amount entering and leaving the circulating pool per unit body mass and time.
The table describes animals after a period without food. Alanine, glutamine and glycine are amino acids.
| Metabolite | Mean turnover flux / nmol g⁻¹ min⁻¹ | Mean blood concentration / mmol L⁻¹ |
|---|---|---|
| Lactate | 410 | 2.8 |
| Glucose | 162 | 8.1 |
| Acetate | 84 | 0.5 |
| Alanine | 74 | 0.3 |
| Pyruvate | 61 | 0.12 |
| Glycerol | 58 | 0.6 |
| Glutamine | 48 | 0.45 |
| Stearic acid | 26 | 1.8 |
| Glycine | 23 | 0.1 |
Separate groups are compared while fasting and while feeding. The scatter plot displays individual measurements and group means.
PowiększLabelled metabolites were also traced into intermediates of the Krebs cycle. The stacked bars show the fraction of carbon input attributable to each of three circulating metabolites in ten tissues. Fractions below 1 leave a contribution from other sources.
PowiększZadanie 1 h.
Evaluate the claim that glucose is the principal circulating substrate used by tissues for respiration, using the supplied evidence.
Korepetytor AI
Nie wiesz, jak ruszyć? Korepetytor zna to zadanie i poprowadzi Cię krok po kroku, bez gotowca.
3 rozmowy · bez karty · Zaloguj się
Sprawdź się
Odpowiedz i oceń, jak poszło. Klucz odsłoń dopiero, gdy masz swoją odpowiedź.
Jak poszło Ci z tym zadaniem?
Wybierz ocenę: zapamięta ją ta przeglądarka, a z darmowym kontem zobaczysz ją na każdym urządzeniu.
Pokaż rozwiązanieUkryj rozwiązanieKlucz i punktacja
Odpowiedź z klucza
The broad claim is not supported for all tissues; the brain is the main exception, with the feeding heart another exception. ✔
Lactate turnover is higher than glucose turnover. ✔
This lactate–glucose difference occurs in both nutritional states. ✔
Glucose gives the largest fraction in the brain and in the feeding heart. ✔
During fasting, lactate or glutamine contributes more than glucose in all tissues except the brain. ✔
During feeding, lactate or glutamine contributes more than glucose except in brain and heart. ✔
Schemat punktowania
Award any 3, maximum 3. An explicit comparison in both states can earn both turnover points. Do not award the overall-conclusion point for an unexplained statement that the claim is both supported and unsupported. Avoid equating proportions with absolute whole-tissue fluxes.