Please note:
- The exam is over, so use this wisely. It will not change your score.
- These answers were written with medium-low care and therefore there are likely to be errors (also forgotten half the content lol). If you see any errors, please let me know and I'll fix them up. * denotes questions that I find debatable.
Multiple Choice
Spoiler
1. B
2. C
3. B
4. C
5. D
6. B
7. D
8. C
9. B
10. A
11. B*
12. C
13. D
14. B
15. D
16. B
17. B
18. A
19. B
20. A
21. C
22. A
23. A
24. B
25. D
26. D
27. C
28. C
29. C
30. C
31. D
32. D
33. D
34. C
35. B
36. D
37. B
38. C
39. A
40. A
Short Answer - these are rough answers, extra detail may be required/not all acceptable responses included.
Question 1
Spoiler
a.
GA = protein packaging into vesicles for secretion
M = site of aerobic cellular respiration
b.
i. Exocytosis
ii. Exocytosis is the energy-dependent mode of transport involving the fusion of secretory vesicles with the plasma membrane before releasing the product into the extracellular environment. Secretory granules are a subset of secretory vesicles, containing the products to be secreted.
Spoiler
a.
From left to right – phosphate, ribose sugar, nitrogenous base (sugar should be specific, e.g. pentose sugar/deoxyribose probz not accepted)
b.
tRNA = facilitates the transport of complementary amino acid to the ribosome during transcription
mRNA = carries the genetic code in the form of RNA for protein production
c.
Addition of a poly A or guanine cap = assist in stability/survivability of the mRNA
Splicing = remove introns and merge exons together, facilitate in production of different proteins from the same sequence of DNA
Spoiler
a.
Enzymes have an optimum temperature at which they operate. Low temperatures = reduce activity, high temperature = denature.
b.
Green light normally reflected and therefore not absorbed. Red light can be absorbed better and therefore can increase the rate of the light dependent stage = increase crop yield.
c.
Apply theory of endosymbiosis. E.g. have their own ribosomes, double membrane.
Spoiler
a.
i. X = receptor protein , Y = nuclear membrane
ii. Exocytosis
b.
1 = reception, binding of signalling molecule with receptor
2 = signal transduction, production of secondary messengers which amplify the signal
3 = response, altered (increased) gene expression
c.
hydrophilic, cannot pass through the plasma membrane and therefore uses an extracellular receptor
Spoiler
a.
Cytotoxic T cells detect changes in MHC 1 expression (i.e. no longer self), using perforin/granzymes to initiate apoptosis or cell death of virally infected cells
b.
i. lymphatic system filters fluid that leaks out of the systemic circulation, which is subsequently checked by immune cells which are located in lymph nodes i.e. facilitates the detection of pathogens
ii. T helper, naïve B cell, binding and production of cytokines in response to complementary binding, clonal selection and expansion, activated B cell, plasma B cell and memory B cells, plasma B cells produce antibodies.
Spoiler
a.
cheaper cost, reduced risk of adverse immune reaction
b.
allergies to the bacteria, many other examples of ethical considerations
Spoiler
a.
substitution point mutation, or missense mutation
b.
i. Standard natural selection question. Those with lactase could use more food sources = selective advantage, increased passing down of favourable allele to children as increased genetic fitness/survivability, increase in frequency of allele
ii. Founder effect, broke off from the original population and didn’t have the allele in the gene pool. Bottleneck effect by the same reason. Can’t think of any reasons why it would be selected against? I suppose people had a cow which produced toxic milk and then all those with the gene died? Lol
c.
Over many generations = selective breeding, breeding those with similar traits together to increase allele frequency.
Spoiler
a.
Amatitlania aiquia and Hypsophyrys nematopus, least amount of time since divergence.
b.
Burial site undisturbed/rapid burying = sediment in ocean rapidly buries and no other land animals trampling over the remains. High pressure = weight of water above
c.
carbon dating can be used, measuring ratio if C12 to C14, as the fish is an organic organism. I’d also argue that relative dating or stratigraphy could also be used. Potassium/argon not relevant here.
Spoiler
a.
Features to talk about include position of less centralised foramen magnum, increased brow ridges, not flat face.
b.
Figure 1 homo egaster and sapiens are depicted to be more closely related together than in figure 2. Also in figure 2, egaster is an ancestor of sapiens instead of the divergent evolution.
c.
Anywhere reasonable, probably just draw another diverging branch off the sapiens and neanderthalensis branch. Justify with the presence of interbreeding/ shared physical characteristics.
d.
contradictory evidence, new evidence, inter-breeding, accuracy of dating techniques
Spoiler
a.
Epidemic = localised to Samoa, pandemic = person arrived on plane, so assume that somewhere else is also infected
b.
babies less than 6 months, protective antibodies from mother via placenta i.e. passive natural immunity
c.
i. Samoa = 31%, Australia = 95% i.e. 64% difference
ii. Active induced immunity
iii. Apply theory of herd immunity i.e. large population vaccinated = protect those who are not since less susceptible hosts to facilitate transmission
d.
hAnD hYgEiNe, quarantine and screening of overseas travellers
Spoiler
a.
I cbs analysing the results :c , but you’d have to describe the bp for each of the different ones since they’ve provided a ladder and also considering the mark allocation. Also slightly explain the results i.e. why longer migrate less.
b.
Test tube 1 missing and half of test tube 2 missing, possible reason is that the guy just injected some buffer into test tube 1 lol or didn’t set it up properly.
c.
Factors include length (as longer = slower), also charge of current (increased = greater attraction, more movement)
d.
wear gloves, have hAnD hYgEiNe,