biology unit 3/4

VIVI

For 2022 vcaa sample MCQ, why is the answer for question 11 (B)?

Pasta

VIVI in both of the aerobic and anaerobic pathways, glycolysis is involved. In order for glycolysis to continue indefinitely, especially for anaerobic respiration, the cell must cycle NADH back to NAD+ for continued use in glycolysis because NAD+ is an input.

lxna

It’s asking you to compare pathway 1 (anaerobic respiration) with pathway 2 (aerobic respiration)

A is not correct because anaerobic respiration does not create a high yield of ATP, it only makes 2

C is not correct because only aerobic respiration occurs in the mitochondria

D is not correct because anaerobic respiration in animals does not make CO2, only in plants/yeast

Therefore B is the only correct answer. This is because both pathways require NADH, which is then unloaded into NAD+ and recycled over and over again

chemistry1111

why is the answer C for question 8 of the NHT 2022 bio exam?

spicynuggets

How do you structure explain questions (after you have included the 'what' and the 'why')? Is there something additional that you have to say?

butterfly13579

Hey guys! Could someone explain how you would structure a response to the process of allopatric speciation for the Howea palm trees?

Smartiestarz

butterfly13579 Hey! I think you meant sympatric speciation in howea palms- this is how I’d structure my responses for that

There is pre-existing genetic variation in the howea palm population with some palms being able o grow better in acidic soil whereas potters growing better in basic soil (likely due to a prior polyploidy mutation which may have been the source of a new allele)
These palms are NOT geographically o isolated, but occupy different niches hence may be exposed to different environments and different selection pressures
Which selected for different phenotypes (ex-the difference sin flowering times). Over many generations as the different mutations accummalate, there is so much genetic and phentoypic variation between the palms that
They are unable to interbreed to produce viable fertile offspring, hence are considered to be reproductively isolated and have formed different/seperate species

butterfly13579

Smartiestarz Thank you so much!!!!

md2112

which new putative homo species are we supposed to know about

chemistry1111

what should we know about strs in dna profiling?

chemistry1111

also with PCR is the temperature for stage 1 denaturation 95 degrees or 96 or a range ? thanks

studyingvce2022

chemistry1111 90-95 degrees Celsius

chemistry1111

For question 4c short answer 2022 biology NHT, how would you answer the question would you outline the humoral immune response?

butterfly13579

Also do you think the exam would be easier than previous years because of the new study design?

clazah

do we need to know crispr in gene editing or bacteria or both?

butterfly13579

clazah I'm pretty sure its both cause there were some questions on trial exams about the use of CRISPR in bacteria

chemistry1111

what are some ethics related to recombinant plamids and insulin production.

_sophiestudies_

chemistry1111 probably discussions surrounding safety and effectiveness of insulin (ensuring benefits outweigh any negatives) and discussions on the use of animal insulin vs human insulin (i.e. animals being killed to obtain insulin that has be found to be less effective as human insulin from recombinant plasmids, meaning according to non-maleficence, the slaughter of these animals should be ceased). There may also be ethical discussions in relation to the economic benefits of human insulin from plasmids as well. That's what came to mind for me at least.

butterfly13579

how do you describe the cell mediated repsonse

Smartiestarz

butterfly13579 For a 4 marker on the cell mediated immune response (this is just a general guide for keywords btw- always link it back to the specific context- ex the name of the virus in the question)

Antigen presenting cell (ex-macrophage) engulfs the virus via phagocytosis and presents the non self antigen on MHC 2 marker on its surface to a helper T cell upon travelling to the lymph node via the lymphatic system
The helper T cell recognises this non self antigen and activates T lymphocytes to undergo clonal expansion and selection producing cytotoxic T cells and memory T cells.
Cytotoxic T cells recognise non self viral antigen presented on MHC 1 markers on surface of virally infected host cell and releases chemicals like perforins to induce apoptosis, destroying that cell
Whereas
Memory T cells will circulate in the blood and lymph providing long term natural active immunity as they trigger a stronger, faster greater immune response to subsequent exposures to the same viral antigen.
Hope I have not missed out on anything 🙂

Christ

_sophiestudies_
We have to also consider that insulin is quite expensive and so following the principle of Justice, the production of insulin has ethical issues as people from a lower socioeconomical background may not be able to afford it.

chemistry1111

_sophiestudies_ could a problem with this is that the bacteria is introduced into insulin gene and therefore causes harm to the individual

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