VCE Biology Questions Thread

erin3

just curious which answer did you pick instead of D?

lune777

B but wasn;t sure

bella0953

B cant be right bc animals in water existed before land animals

lune777

Yeah my question wasn't about what I picked, it was about why D is the answer. I didn't get what the last 2 organisms are for option B?

S007

lune777 So they kinda did a trick to that question. It says ground surface at the top meaning that its the oldest and it makes sense that dinosaurs skull would be one of the oldest. And the really detailed fossil should be at the top as we can see it is the least decomposed as it has a lot of details to it compared to the other fossils shown.

lune777

S007 ohhh i see thank you!! So the really detailed one is the oldest. Do you happen to know what it is? I can't seem to find anything about it

sarah99

hey! I was just wondering why O2 being a competitive inhibitor is an issue - can't plants just use up the O2 in ETC or is it not fast enough? so do they need to take O2 in all over again for ETC?

S007

sarah99 o2 is only an issue in photosynthesis where it leads to photorespiration and glucose is not produced. but when it comes to cellular respiration it is no issue and it acc needs o2 as an input (in aerobic respiartion). My advice don't try to like yk get urself confused just make them isolated from one another (the processes). photosynthesis is for the plant to provide itself glucose to make the complex molecule startch and cellular respiration provides energy and both glucose and energy enable the plant to grow. i hope that answered your question

sarah99

Also does anyone have a good explanation for why Q12 of 2024 NHT is D? I'm rlly confused lol

lune777

sarah99 yeah i don't rlly get that one too lol

S007

sarah99 I COULD SAY THE SAME. like even chat gpt was confused on why it is D 😭 I got no help on that one I need help for it too 😭

usernotfound

sarah99
During the period of darkness, only cellular respiration is occurring (50 ml/hr average oxygen used for cell resp.)
During the period of bright light, however, both photosynthesis and cellular respiration is occurring, and it is shown that the NET average oxygen released is 200 mL/hr. It is already known that cellular respiration is using 50 ml of oxygen per hour, thus 250 ml of oxygen must also be released per hour during photosynthesis, so the NET average oxygen released is 200 mL/hr.

Sorry if this is a bad explanation, I'm also doing bio lol

S007

lune777 NOOO soorry my explantion wasnt clear its the youngest THE MOST DETAILED IS alwaysss the youngest REEMEMBER THAT. and the question flipped the layers sort of by ground surface they mean the lowest layer and then u go up (but in the question ur going down) so they basically try to trick people. i hope this made more sense.

lune777

S007 ALLGG no i think we're both saying the same thing
like the trilobite thing is the weird detailed one that's the oldest, but the dinosaur is the youngest as per the answer D

lune777

S007 you know its really cooked when chat gpt doesn't get it lmao

lune777

also why is Q24 from 2023 exam A and not C? Is it because each year is independent of the previous one or smth?

S007

lune777 According to VCAA, you probably already read it while marking, but if you didn't, they wrote that the treatment would be most effective when the mean decrease in prescriptions is the lowest (year 9). As this study is done over many years, no significant increase in the need for prescriptions signifies the long-term and sustained effects, hence option A.
Despite the big jump between the first and second years, it still became increasingly effective over the years. So, the AIT does have a long-term sustained effect.

sarah99

Hey just wondering if photorespiration is slower than/produces less O2 photosynthesis?

I came across a question about an underwater plant Elodea - and whether O2 production (as output counted by number of bubbles) would increase decrease or stay the same if the students added more O2 to the solution.

I was thinking since technically the calvin cycle will still use up ATP and NADPH and re-cycle the unloaded forms back to LDS, they can be used and O2 can be produced again, so maybe it would have no effect?

S007

O2 production would stay the same because its not involved in the calvin cycle. for a plant to produce O2 it just needs water. the water enters the LDS and is split into 2 hydrogens and oxygen. Two oxygens from split water then join together to form O2 and then are released whereas the H+ is taken up by NADP+ so becomes NADPH and the hydrogen is used in the LIS to make the final product glucose. is that what you were asking about? let me know. if it was I hope it made sense

sarah99

yes makes sense - thanks!! I was also thinking the same thing. I was also considering that light independent stage will unload ATP and NADPH into ADP and NADP+ right, so possibly if photorespiration is slower than photosynthesis, these co-enzymes might reach the light dependent stage slower, meaning O2 produced might be less.
but yeah, not sure and might not be tested

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