Helicase - think of helicopter and its blades cutting through the hydrogen bonds of DNA as an analogy
Ttubes
- Joined Aug 14, 2022
md2112 Straight off the bat you had to recognise that anaerobic fermentation was producing the Co2
So i think (note he word think), the mark allocation would be:Recognition that the wheat seeds were anaerobically fermenting because of low oxygen conditions preventing aerobic respiration
The process is faster than aerobic respiration and thus would show a consistently high level of CO2 production (this is what my teacher advised)
This process produces CO2
However after a period of time a decrease inn CO2 levels is observed as the accumulation of ethanol as a by product would accumulate and may be toxic OR because of the inefficiency of anaerobic fermentation (produces less ATP per glucose molecule) the glucose storages of the seed would run out
Again this is not a definitive guide but close enough
md2112 this was from prior knowledge, And I really do understand your point about this text lacking information, but perhaps the fact that they were found in Indonesia????? Its a bit of a stretch, but I have heard sample exams for VCE indicate the type of questions we'll be given and not necessarily the actual content, like from this article we can perhaps expect a "similar case study" were we have to explain concepts but in the context of the article
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md2112 The explanation is that H. floresiensis had a much small stature and couldn't be the ancestor of the otherwise taller Indigenous Australians. H. densiova can't be because they share only a small percentage of DNA, and if it was the ancestor it would show much greater genetic similarity, thus the small percentage of DNA similarity would be because of interbreeding rather than descent. For example, Neanderthals and modern H.sapiens share max 5-7 percent (smth like that) DNA in common, but we say they shared a common ancestor and interbred rather than Neanderthals being the ancestor of H.sapeins, the same logic applies here.
Christ Hi! Yes I understand the fact about the mRNA not containing introns, however if you read the entire sentence together "The insulin produced by recombinant DNA technology is produced from human insulin mRNA," though accurate is not as good as "The insulin produced by recombinant DNA technology is produced by a cloned human insulin gene."
And the reason why C is a better answer is because the mRNA undergoes further processing as you mentioned to convert into into DNA, and hence its not actually the mRNA producing the insulin but rather the copy DNA produced by Reverse transcriptase (invertase in an enzyme that catalyses sugar btw). Thus C would be a better answerchemistry1111 No, trp is an amino acid and its not because of its toxicity the trp operon exists, but rather its synthesis is very energy costly, so continual expression of the trp genes could deplete the cell of ATP. And that's why these structural genes are regulated in an operon to conserve this ATP when trp is already present
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Just to add to _sophiestudies_ reply. Though the study design states both an induced fit model or the lock and key model can be used to explain enzymes. Usually the induced fit model (in which the enzyme changes its shape to accommodate to the substrate because they're not perfectly complementary like the lock and key) receives more support for this exact reason. In the process of accommodating its shape to fit the substrate it stress the bonds (intramolecular) within the substrate and brings it to a state where it more favorable to react - hence decreasing the activation energy for the reaction.
- “What you egg!”
Hey guys. I was thinking about c)ii) from the sample exam, and an idea came up to use "111 mitochondrial genomes exist" as how "mtDNA phylogeny provides evidence" Just wondering if my line of thought would be correct:
"Genomes" suggests that they are distinct gene pools (in terms of mtDNA). If gene flow was possible between these populations there would be one genome with high variation not separate genomes
Hence they must have been present in Australia for the genetic variations caused and accumulated by natural selection, genetic drift and mutations for the genomes to become separate/"diverge"
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Hi guys, I was just wondering if any of you could review and guide me with answering Question 9 of the sample examination for 2022 VCE.
a) Homo heidelbergensis that evolved into Homo sapiens 300,000ya in Africa and then migrated to Australia 50,000 ya. Already present before the arrival of the ancestors of Indigenous Australians was Homo erectus - an earlier hominin- that had previously migrated out of Africa and had diverged into Homo floresiensis in Indonesia also coexisted with Homo sapiens.
b) Migration to Australia occurred in 2 distinct pathways, were one group reached and travelled along the East coast 40,000 ya and the 2nd group travelled across the western coast and settled 41000, because the 2 main groups were geographically isolated by Australia's mainland, gene flow was limited and hence different mutations occurred and accumulated in each population's genome
c)i) Evidence of art (cultural evolution) such as cave paintings
The presence of stone toolsc)ii) The large genetic variation in mtDNA indicates that a long time had elapsed since migration hence the time for mutations to accumulate, supporting a continuous presence in Australia as well as in discrete areas as many different mutations occurred in specific isolated population and hence accumulated because of the lack of gene flow leading to 111 mtDNA genomes to diverge
Thanks
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God
Hi,
I agree with your first point. But in that VCAA question by determining absolute age of the igneous rock you could determine the absolute age of the ancient mollusk (as specified in the stem) by using relative dating techniques, since its found in the same stratum (after first using absolute dating techniques on the igneous rock), so would finding the relative age of the ancient mollusk (in the same stratum as the dated igneous rock) be used to determine its absolute age of 50 my???? So is it also possible for it to be the other way around????
So all in all what technique would it be: absolute or relative???Moskva
Thank you it makes sense. But this VCAA question is kind of confusing, like I understand the answers but I'm confused on how to categorize it. 2018 NHT 7 b and c in which it asks how the ABSOLUTE AGE can be determined using the ancient mollusk (similar to index fossils in the sense of providing RELATIVE age), so it is a relative dating technique that can provide ABSOLUTE AGE or it is an absolute dating technique.Thank you once again
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Just want to confirm if my reasoning is right and ask a question about how index fossils are use to date other fossils found in the same strata:
Firstly radiometric dating is utilized to date igneous rock associated with (near) sedimentary layer that the index fossil is found within, percentage of parent isotope is compared to broken down products, hence using stratigraphy it can be inferred that the age of the index fossil = ____.
Using stratigraphy, the fossil found in the same strata is the same age as the index fossil, ____.
So if the question asked whether using index fossils is absolute or relative (point 2) what would be say?
Relative - because the age of the fossil is being determined by using the index fossil nearby?
or Absolute - because the NUMERICAL value of the fossil is known because of the INDEX fossils whose NUMERICAL age is also known?
bioho4
Tbh this question is very similar to: Are viruses eliminated by the humoral response or the cell mediated response?
In theory both are activated.But I think the more prominent one would be the cell mediated response. Because it seems more likely that the different markers on the transplant would be recognized as an intracellular threat rather than an extracellular threat, because its on a cell rather than in the blood (where the humoral response is more efficient), like you won't really have the donors cells floating around in the blood, though the humoral response would still be initiated.
Hence, I would talk about the cell mediated response rather than the humoral if no information is provided. However, VCAA is very specific in the language it uses for example in the sample exam 2022, 4c short answer, it specifically mentions the response against an intracellular pathogen (cell mediated) so I think if this question was to be asked there would be more context behind it to determine which pathway of the adaptive response needs to be mentioned.
