ATAR Notes: Forum

Archived Discussion => Mathematics/Science/Technology => 2015 Exam Discussion => Biology => Topic started by: The Peasant on October 30, 2015, 11:58:28 am

Title: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 11:58:28 am
So...how did everyone go?
Title: Re: Post Exam Discussion
Post by: Jay.C on October 30, 2015, 12:00:38 pm
Was the last question multi regional or out of Africa?
Title: Re: Post Exam Discussion
Post by: djsbrks on October 30, 2015, 12:02:23 pm
Was the last question multi regional or out of Africa?
If its not out of africa I will cry
Title: Re: Post Exam Discussion
Post by: Jay.C on October 30, 2015, 12:03:03 pm
If its not out of africa I will cry

Omg no I did multi regional
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:03:43 pm
Was the last question multi regional or out of Africa?

That question fuqed me up. Don't even know which one it is. Anyone else?
Title: Re: Post Exam Discussion
Post by: djsbrks on October 30, 2015, 12:05:27 pm
Omg no I did multi regional
Dw I couldnt remember the other so I put out of africa. Its probably multi regional now that I think about it ._.
Title: Re: Post Exam Discussion
Post by: djsbrks on October 30, 2015, 12:07:19 pm
Anyone else feel like some of the multiple choice qs were mini essays... :/
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:08:36 pm
I wasnt even sure how to use the evidence. Couln't even relate it to the theory properly. Btw, what did people write for the very last question (timing and what ever the other thing was).
Title: Re: Post Exam Discussion
Post by: Individu on October 30, 2015, 12:09:59 pm
What did you guys put for how neurons die - I said the membrane of the axon is pierced, creating a hole and thereby causing an influx of sodium ions into the axon and causing potassium ions to rush out of axon, disrupting action potential / action potential cannot be generated leading to the death of the neuron. Is this correct?
Title: Re: Post Exam Discussion
Post by: Callum@1373 on October 30, 2015, 12:11:11 pm
Not doing Bio 3/4, but the year 12's just walked out and from what i've heard the exam was ridiculous lol  :-\
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:12:58 pm
It was multi regional for the last question
Title: Re: Post Exam Discussion
Post by: djsbrks on October 30, 2015, 12:13:30 pm
It was multi regional for the last question

damn
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:13:56 pm
Not doing Bio 3/4, but the year 12's just walked out and from what i've heard the exam was ridiculous lol  :-\

Overall, the exam was alright, about the same difficulty as last year. But some of the questions were really cryptic - couldn't even tell for sure what the question wanted. 
Title: Re: Post Exam Discussion
Post by: Yacoubb on October 30, 2015, 12:14:40 pm
Congrats on finishing guys! I'll be happy to upload my version of answers if someone can get the exam scanned & uploaded! :)
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:18:18 pm
It was multi regional for the last question

What's your reasoning?
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:20:10 pm
Overall, the exam was alright, about the same difficulty as last year. But some of the questions were really cryptic - couldn't even tell for sure what the question wanted.

It was harder than last year. There were no easy genetic cross questions in this one
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 12:21:53 pm
Ermagherd.

IMO, that was definitley harder than last year, way less easy recall marks and no experimental design! (Unless I missed it oops)
I definitley bombed..... Reduced workload is not looking as probable for next year after that.

I also did Out of Africa, purely because I completely forgot what the Multiregional hypothesis even was  :'(
Also, did ADP+Pi count as one of the input molecules for the light dependent reactions?

 :-\
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:23:53 pm
Ermagherd.

IMO, that was definitley harder than last year, way less easy recall marks and no experimental design! (Unless I missed it oops)
I definitley bombed..... Reduced workload is not looking as probable for next year after that.

I also did Out of Africa, purely because I completely forgot what the Multiregional hypothesis even was  :'(
Also, did ADP+Pi count as one of the input molecules for the light dependent reactions?

 :-\

Most people did out of Africa I think
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 12:24:14 pm
I think adp + Pi should be alright
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:25:46 pm
Lol I still dont understand why it's multiregional. I know I screwed that question up, so I'm probs wrong.

What did people get for the mc with the trait involving the mtDNA?

Title: Re: Post Exam Discussion
Post by: Yacoubb on October 30, 2015, 12:27:50 pm
Guys just remember that a hard exam means that A+ would be granted for a lower percentage than normal! General consensus from what I've heard is that it was a tricky exam!
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:29:44 pm
Also, what did people write for the fish hypothesis? The one with different fossils in different strata?
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 12:31:23 pm
Lol I still dont understand why it's multiregional. I know I screwed that question up, so I'm probs wrong.

What did people get for the mc with the trait involving the mtDNA?

Yeah I screwed up the Africa as well, that multiple choice was d I think
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 12:34:05 pm
Also, what did people write for the fish hypothesis? The one with different fossils in different strata?

I put that ocean predators were introduced in the middle of the time period, creating a selective advantage for a large dorsal spine as it would scare away the predators. Then the predator died out and spine sizes returned to normal gradually.

Do you think that would be right/get a mark??
Title: Re: Post Exam Discussion
Post by: Individu on October 30, 2015, 12:34:27 pm
Also, what did people write for the fish hypothesis? The one with different fossils in different strata?
For the 1 mark question, I said the environment changed from freshwater --> ocean like water --> freshwater.
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 12:35:20 pm
For the 1 mark question, I said the environment changed from freshwater --> ocean like water --> freshwater.

I just said the change of water salinity
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:36:16 pm
Yeah I screwed up the Africa as well, that multiple choice was d I think

Was the trait supposed to be X linked?
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 12:36:38 pm
I said out of africa wtf?
How is it multi regional wow i cant believe i did not realise this, add another 5 marks to my misfortunes...

I said out of africa because it said modern humans came from africa, and that modern humans did not share neanderthal DNA. wow....
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 12:37:39 pm
Was the trait supposed to be X linked?

no it was mitochondrial, so only from mother to offspring, i got d too
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 12:38:56 pm
I said out of africa wtf?
How is it multi regional wow i cant believe i did not realise this, add another 5 marks to my misfortunes...

I said out of africa because it said modern humans came from africa, and that modern humans did not share neanderthal DNA. wow....

I said out-of-africa aswell.

Can somebody explain to me how it's multi-regional hypothesis?
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 12:39:15 pm
I put that ocean predators were introduced in the middle of the time period, creating a selective advantage for a large dorsal spine as it would scare away the predators. Then the predator died out and spine sizes returned to normal gradually.

Do you think that would be right/get a mark??

I literally had no idea, just went majorly general and said that the phenotypic makeup of the fish population changed in response to the changing selection pressures of their lake environment.

Pretty sure I was too general in like 50% of questions - I'm really not optimistic at all any more.....


Was the trait supposed to be X linked?
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:39:28 pm
I said out of africa wtf?
How is it multi regional wow i cant believe i did not realise this, add another 5 marks to my misfortunes...

I said out of africa because it said modern humans came from africa, and that modern humans did not share neanderthal DNA. wow....

Don't worry. If you didn't get it then no one did
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:41:06 pm
I just said the change of water salinity

Damn. I screwed it up then. Wasn't specific enough. Did it say anything about salt/ocean water and the dorsal etc traits in the stem question? I just wrote that the selection pressures changed drastically for a period of time, which selected for "" traits.
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 12:41:52 pm
Damn. I screwed it up then. Wasn't specific enough. Did it say anything about salt/ocean water and the dorsal etc traits in the stem question? I just wrote that the selection pressures changed drastically for a period of time, which selected for "" traits.

No, i you're right as well. You basically explain the same idea
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 12:42:57 pm
Don't worry. If you didn't get it then no one did

how do you know multiregional was the answer im so depressed rn
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 12:43:56 pm
how do you know multiregional was the answer im so depressed rn

my teacher said it was out-of-africa so idk
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 12:44:09 pm
my teacher said it was out-of-africa so idk

same.
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 12:44:17 pm
what did guys get for the DNA mc question, antiparallel or double helix?

and the linked genes... oh man... what did you circle ? :(
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 12:45:09 pm
what did guys get for the DNA mc question, antiparallel or double helix?

and the linked genes... oh man... what did you circle ? :(

Antiparrallel

I think i circled the second one (i don't really remember)
Title: Re: Post Exam Discussion
Post by: Yacoubb on October 30, 2015, 12:45:17 pm
Do you have the exact question for the mutli-regional or Out of Africa Hypothesis question? I may be able to answer it and give my 2 cents...
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:45:27 pm
how do you know multiregional was the answer im so depressed rn

I don't know guys. My teacher said it was multi regional. Maybe they accept both
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 12:46:13 pm
same.

they better give us marks for out of africa because:

It said AFRICAN DESCENDED HUMANS did NOT have Neanderthal DNA, and hence they did not interbreed = out of africa
Where as multi regional, even the african descended humans would have neanderthal DNA because interbreeding would be common

Such an ambiguous question...


Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:46:41 pm
Antiparrallel

I think i circled the second one (i don't really remember)

Pretty certain it was the 2nd one
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 12:46:55 pm
Antiparrallel

I think i circled the second one (i don't really remember)

same but what did you support it with? I made up the biggest bs...
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 12:47:49 pm
Well, i think i need to put this stupid bio exam behind me and focus on the upcoming further exam
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 12:48:12 pm
I don't know guys. My teacher said it was multi regional. Maybe they accept both

Let's pray that they'll take either, depending on your justification....

I wonder around what mark the A+ cutoff will be?
Title: Re: Post Exam Discussion
Post by: LoadedWithPotatoes on October 30, 2015, 12:49:22 pm
A+ cut off will probably be around low 90s again..
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:52:17 pm
A+ cut off will probably be around low 90s again..

Honestly the only hard questions were the last 2. Can't believe there was so little on inheritance
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 12:52:27 pm
The question about the comparison of structures in fossils was so unexpected.. i got it so wrong
Title: Re: Post Exam Discussion
Post by: Alsci on October 30, 2015, 12:52:42 pm
An A+ last year was 87%
Title: Re: Post Exam Discussion
Post by: TwinNerd on October 30, 2015, 12:52:52 pm
Let's pray that they'll take either, depending on your justification....

I wonder around what mark the A+ cutoff will be?

 I thought that the exam was pretty good, easier than last year in my opinion. However, I thought the multiple choice questions were a bit tricky like some of them I had to toss up between to answers. People at my school had mixed response some saying it was okay others saying it was a disaster

I think the last question you could write either out of africa or multi regional as long as your reasoning is right.
I think I stuffed up the piercing membrane question...
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:53:35 pm
my teacher said it was out-of-africa so idk

I honestly think that its out of africa. I'll try reason for this.
So basically homo sapiens evolved in africa first before emigrating and displacing other homo species.
-I think that the DNA evidence also supports this
-So basically why the African individuals do not have neanderthal DNA is because their homo sapien ancestors remained in Africa, instead of migrating.
-Other homo spaiens (which originally evolved in Africa) moved to other continents (from africa to middle east -->europe/east asia---. and finally Australia). Basically interbreeding occured and hence neaderthal dna exists in homo sapiens of which inhabited these regions.
So both DNA evidence supports this.

I honestly didnt write my answer like this (I panicked and contradicted myself to rip marks).
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 12:53:42 pm
The question about the comparison of structures in fossils was so unexpected.. i got it so wrong

ahah i guessed comparative morphology.
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 12:55:04 pm
I thought that the exam was pretty good, easier than last year in my opinion. However, I thought the multiple choice questions were a bit tricky like some of them I had to toss up between to answers. People at my school had mixed response some saying it was okay others saying it was a disaster

I think the last question you could write either out of africa or multi regional as long as your reasoning is right.
I think I stuffed up the piercing membrane question...

For the membrane one I put that the extracellular fluid would come into the cell changing the pH of the neuron and preventing chemical reactions catalysed by enzymes from occurring, causing cell death
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 12:55:41 pm
The question about the comparison of structures in fossils was so unexpected.. i got it so wrong

Was it comparative morphology or comparative anatomy? Lel I am defintiley not getting an A+ unless it was out of Africa AND I didn't drop a mark on MC...
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 12:56:27 pm
I thought that the exam was pretty good, easier than last year in my opinion. However, I thought the multiple choice questions were a bit tricky like some of them I had to toss up between to answers. People at my school had mixed response some saying it was okay others saying it was a disaster

I think the last question you could write either out of africa or multi regional as long as your reasoning is right.
I think I stuffed up the piercing membrane question...

How did you find that easier than last year. Last years exam was the easiest exam I've done
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 12:57:07 pm
Was it comparative morphology or comparative anatomy? Lel I am defintiley not getting an A+ unless it was out of Africa AND I didn't drop a mark on MC...

According to my teacher who marks the papers, it's not on the study design so everyone should get a mark as long as they wrote something..........
Title: Re: Post Exam Discussion
Post by: LoadedWithPotatoes on October 30, 2015, 12:57:30 pm
How did you find that easier than last year. Last years exam was the easiest exam I've done

Yeah.. honestly found this year's exam much harder than the 2013 and 2014 one.
Title: Re: Post Exam Discussion
Post by: warya on October 30, 2015, 12:58:28 pm
No joke I was staring at that meiosis diagram for a good 10 minutes
The gene cloning mcq, was it because bacteria undergo mitosis exponentially?

The linked genes question took me ages, I ended up drawing a corss and wrote one line of justification hope its enough haha
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 12:59:02 pm
ahah i guessed comparative morphology.

Likewise. I wrote comparative morphology as well. Pretty sure its right.
Title: Re: Post Exam Discussion
Post by: BakedDwarf on October 30, 2015, 01:00:00 pm
No joke I was staring at that meiosis diagram for a good 10 minutes
The gene cloning mcq, was it because bacteria undergo mitosis exponentially?

The linked genes question took me ages, I ended up drawing a corss and wrote one line of justification hope its enough haha

Bacteria don't undergo mitosis
Title: Re: Post Exam Discussion
Post by: Alsci on October 30, 2015, 01:00:23 pm
No joke I was staring at that meiosis diagram for a good 10 minutes
The gene cloning mcq, was it because bacteria undergo mitosis exponentially?

The linked genes question took me ages, I ended up drawing a corss and wrote one line of justification hope its enough haha

I also said bacteria undergo mitosis exponentially
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 01:01:06 pm
Yeah.. honestly found this year's exam much harder than the 2013 and 2014 one.

Lucky you, I found 2014 so so easy, and this years, well, awful to be honest. I don't know if the exam was necessarily that much harder, but 2014 kind of played to my strengths, if you will, whereas this exposed my weaknesses.
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 01:01:34 pm
what gametes did you guys write for the linked genes question? the crossing over and non-crossing over?

i put the left but apparently it's the middle
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 01:05:12 pm
i did the middle one but guessed it, but i was referring to the table question where you had to put crossed over gametes and non crossed over gametes. did anyone else only have two gametes for the crossing over? far out i know i did this one wrong i had absolutelty no idea..

i just swapped the top and bottom to get the other two combinations? idk if that's right
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 01:07:29 pm
i just swapped the top and bottom to get the other two combinations? idk if that's right

Yep that's right
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 01:08:36 pm
wait did you write them as the bb/aa or what? damn i thought they were meant to be like just gametes like aa or bb ? omg... :(

I did like B/r and b/R or whatever it was and then r/B and R/b so yeah i think you had to write them with the linked notation
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 01:10:18 pm
wait did you write them as the bb/aa or what? damn i thought they were meant to be like just gametes like aa or bb ? omg... :(

No you don't have the lines for gametes
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 01:11:12 pm
No you don't have the lines for gametes

seriously?! ughhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
Title: Re: Post Exam Discussion
Post by: lmnop on October 30, 2015, 01:11:44 pm
I did like B/r and b/R or whatever it was and then r/B and R/b so yeah i think you had to write them with the linked notation

I drew the gametes instead, would that suffice?
Title: Re: Post Exam Discussion
Post by: julijulib on October 30, 2015, 01:13:07 pm
I drew the gametes instead, would that suffice?

can't remember if it strictly asked for the genotypes but if not that sounds good
Title: Re: Post Exam Discussion
Post by: warya on October 30, 2015, 01:14:49 pm
It said crossing over didnt occur so I put Br Br br br
and if it did occur then bR Br bR Br

Bacteria dont undergo mitosis omg that was so stupid of me hahaha
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 01:15:28 pm
I drew the gametes instead, would that suffice?

Didn't it ask for the gametes
Title: Re: Post Exam Discussion
Post by: sayy11 on October 30, 2015, 01:16:39 pm
What did everyone write for the first question on aggregates?
Title: Re: Post Exam Discussion
Post by: sayy11 on October 30, 2015, 01:18:25 pm
It said crossing over didnt occur so I put Br Br br br
and if it did occur then bR Br bR Br

Bacteria dont undergo mitosis omg that was so stupid of me hahaha

Wrote that too, couldn't figure out the evidence for the genotype though on the next question
Title: Re: Post Exam Discussion
Post by: djsbrks on October 30, 2015, 01:19:35 pm
ahah i guessed comparative morphology.
I wrote that too! Except I had bio in front of comparative
Title: Re: Post Exam Discussion
Post by: C.A.T on October 30, 2015, 01:20:13 pm
Overall, the exam was alright, about the same difficulty as last year. But some of the questions were really cryptic - couldn't even tell for sure what the question wanted.

Yes - I agree. Sometimes I answered questions with answers I knew were right but had no idea if they were even remotely answering the question. There was one in particular that was confusingly vague... Can't remember which
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 01:21:11 pm
What SS are people hoping for, realistically?
Title: Re: Post Exam Discussion
Post by: LoadedWithPotatoes on October 30, 2015, 01:21:46 pm
Still reckon the cut-off is probably similar to 2013, maybe 92-94. If it's higher than 96 that's crazy.
Title: Re: Post Exam Discussion
Post by: djsbrks on October 30, 2015, 01:24:28 pm
i did the middle one but guessed it, but i was referring to the table question where you had to put crossed over gametes and non crossed over gametes. did anyone else only have two gametes for the crossing over? far out i know i did this one wrong i had absolutelty no idea..
I circled the middle one at the last minute and wrote a 4 worded justification, didnt even have time to read the actual question lol
Title: Re: Post Exam Discussion
Post by: C.A.T on October 30, 2015, 01:31:50 pm
Still reckon the cut-off is probably similar to 2013, maybe 92-94. If it's higher than 96 that's crazy.

What is the cut-off? Like what does it mean?
Title: Re: Post Exam Discussion
Post by: lmnop on October 30, 2015, 01:32:51 pm
Didn't it ask for the gametes

This is pretty much what I did for the first part (or something like that). I don't really remember the rest of the question though.
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 01:40:52 pm
What SS are people hoping for, realistically?

42+
Title: Re: Post Exam Discussion
Post by: grindr on October 30, 2015, 01:42:59 pm
Completely stuffed up that gamete question... was it only two marks?

and also the very last when about when Aboriginals were present in Australia... what did u get? I got really confused -.-
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 01:43:13 pm
Still reckon the cut-off is probably similar to 2013, maybe 92-94. If it's higher than 96 that's crazy.

No way. 2013 was incredibly simple. I doubt it will be more than 92
Title: Re: Post Exam Discussion
Post by: djsbrks on October 30, 2015, 01:44:17 pm
I think regardless of the outcome, we should all be proud of ourselves. Obviously this year's exam wasn't easy but we tried our best and it won't be the end of the world if you don't get your desired result. Good job 2015 biology students!!!! ;)
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 01:46:49 pm
Completely stuffed up that gamete question... was it only two marks?

and also the very last when about when Aboriginals were present in Australia... what did u get? I got really confused -.-

That one part was 2 marks but I think 4 marks overall??
Title: Re: Post Exam Discussion
Post by: C.A.T on October 30, 2015, 01:49:41 pm
i am no way confident of my answer but i said :

route: the african hominins migrated out of africa and into europe, east asian and middle east and then made their way to australia
time: 80000 years ago (this is for sure incorrect, i guessed this)

Hope you're not incorrect because I said exactly the same thing
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 01:50:53 pm
I've finished bio, I'm home and I'm eating nuggets, it's time to move on with my life.

Ps I said approx 60,000 years, because they must have migrated after interbreeding.
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 02:22:36 pm
i am no way confident of my answer but i said :

route: the african hominins migrated out of africa and into europe, east asian and middle east and then made their way to australia
time: 80000 years ago (this is for sure incorrect, i guessed this)

lol didnt properly understand what the time question meant, (tried to see if i had to estimate a time), but thought that that wasnt what I was supposed to do so I said some bs that didnt make sense. fml
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 02:27:53 pm
im probably wrong dw

what did you guys write for that radioactive dating question 1:1 ratio?

1.25 billion years. (since only one half life occured)

edit* million years or what ever it was lol
Title: Re: Post Exam Discussion
Post by: grindr on October 30, 2015, 02:29:03 pm
im probably wrong dw

what did you guys write for that radioactive dating question 1:1 ratio?

I said 1.25 billion yrs
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 02:32:40 pm
yeah it should be 1.25 billion

Edit: just answering some other questions, i wrote that humans migrated through the middle east and east asia to australia, and for the timing i wrote that they likely passed east asia around 60,000 years ago

The linked genes questions i felt pretty confident on, a question on linked genes was on one of the past exams so i studied it a bit
Title: Re: Post Exam Discussion
Post by: Individu on October 30, 2015, 02:35:25 pm
This is pretty much what I did for the first part (or something like that). I don't really remember the rest of the question though.

I thought they just asked for the genotypes of the gametes.. Like, you just write in BR, br etc. - not the entire chromosome?
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 02:36:44 pm
I thought they just asked for the genotypes of the gametes.. Like, you just write in BR, br etc. - not the entire chromosome?

Yep that should be right, in the box right? on the next page the answer was the middle one with Br/bR
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 02:37:35 pm
I thought they just asked for the genotypes of the gametes.. Like, you just write in BR, br etc. - not the entire chromosome?

Yeah, asked for genotypes of gametes only. And yeah, it was the middle one that was circled.
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 02:46:55 pm
so in the first short answer question how did the aggregates cause cell death, looking back now i think it might've had something to do with the spiky bits piercing cells or something but i wrote something about inhibiting enzymes
Title: Re: Post Exam Discussion
Post by: lmnop on October 30, 2015, 02:48:58 pm
Yep that should be right, in the box right? on the next page the answer was the middle one with Br/bR

Dammit....yeah it was the question with the boxes.
I did circle Br/bR so hopefully my justification is sound enough.
For the amino acid question, did you guys include Met (or something like that) as part of your answer?
I ask because the next question regarding the position of the fifth amino acid tripped me up quite a bit
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 02:52:24 pm
Dammit....yeah it was the question with the boxes.
I did circle Br/bR so hopefully my justification is sound enough.
For the amino acid question, did you guys include Met (or something like that) as part of your answer?

i think i had 8 amino acids?

and for the cell death question, i said because the cell membrane is pierced, there will be no regulation of sodium and potassium ions in/out of the neurones, and so there will be also no action potentials too which will cause them to die? idk.. :(

for the mutation, i said switch I think it was A with C so that a stop codon would be produced and only five triplets were coded for?
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 02:52:43 pm
For the amino acid question, did you guys include Met (or something like that) as part of your answer?

do you mean the one where a mutation causes the chain to shorten? Yeah include met or whatever and i think it ended up being 7 amino acids long in the first part. cant remember exactly

Edit: yeah it couldve been 8, something along those lines
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 03:03:15 pm
so in the first short answer question how did the aggregates cause cell death, looking back now i think it might've had something to do with the spiky bits piercing cells or something but i wrote something about inhibiting enzymes

Yeah, I though it was a question asking about the structure, so I wrote something wrong for that aswell. Should've been something like: "The star shape structure enable the amyloid beta protein to pierce the membrane, causing the celluar contents of the neurons to spill out (essentially induces necrosis/inability for celluar metabolism to continue), hence the neurons are unable to function and as a result, brain cells (which are composed of mostly neurons) die off. The death of neurons produces the symptoms of "" disease"

Probs talk about how there are no action potentials generated or something like that.

Title: Re: Post Exam Discussion
Post by: tashhhaaa on October 30, 2015, 03:03:50 pm
do you mean the one where a mutation causes the chain to shorten? Yeah include met or whatever and i think it ended up being 7 amino acids long in the first part. cant remember exactly

Edit: yeah it couldve been 8, something along those lines

oh damn I wrote 6 for some reason

realising I did worse than I thought
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 03:08:25 pm
Also- what did people write for the vaccine question? It was 4 marks...
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 03:10:53 pm
something about it being attenuated, and causes the production of memory cells and antibodies, which grant the person long term immunity, then i wrote something about subsequent exposures
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 03:15:19 pm
something about it being attenuated, and causes the production of memory cells and antibodies, which grant the person long term immunity, then i wrote something about subsequent exposures

Same
Title: Re: Post Exam Discussion
Post by: cosine on October 30, 2015, 03:24:18 pm
differences between humoral and cell-mediated?

what was the valve question, is it just there to ensure one way flow?

what cells are found in lymph nodes for innate immunity (macrophages?) and adaptive (plasma B cells?)

also was it 8 or 7 amino acids coded i cant remember im having bad thoughts about this :(
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 03:28:46 pm
differences between humoral and cell-mediated?

what was the valve question, is it just there to ensure one way flow?

what cells are found in lymph nodes for innate immunity (macrophages?) and adaptive (plasma B cells?)

also was it 8 or 7 amino acids coded i cant remember im having bad thoughts about this :(

8 amino acids and natural killer cells maybe??
Title: Re: Post Exam Discussion
Post by: Individu on October 30, 2015, 03:29:46 pm
differences between humoral and cell-mediated?

what was the valve question, is it just there to ensure one way flow?

what cells are found in lymph nodes for innate immunity (macrophages?) and adaptive (plasma B cells?)

also was it 8 or 7 amino acids coded i cant remember im having bad thoughts about this :(
Rest assured I'm pretty much certain (99.9% sure) it was 8.
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 03:30:53 pm
8 amino acids and natural killer cells maybe??

Likewise. 8 Amino Acids.
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 03:34:36 pm
differences between humoral and cell-mediated?

what was the valve question, is it just there to ensure one way flow?

what cells are found in lymph nodes for innate immunity (macrophages?) and adaptive (plasma B cells?)

also was it 8 or 7 amino acids coded i cant remember im having bad thoughts about this :(
Cant remember what i wrote for differences but i remember writing macrophages for innate and for adaptive the question mentioned an established rough endoplasmic reticulum so i wrote about plasma cells, the exam has been scanned so ill check it now

Edit, yep its 8
Title: Re: Post Exam Discussion
Post by: b00typizza on October 30, 2015, 03:36:41 pm
What SS are people hoping for, realistically?

Before the exam I was thinking definitely 42+, but after that hellish exam I'll be happy with even a 30
I think the easy psych exam the day before made me too relaxed about exams haha
Title: Re: Post Exam Discussion
Post by: Sine on October 30, 2015, 03:41:46 pm
first 10 SA questions I thought I did really well maybe lost a few marks but the last one was horrendous.

whats the thought on A+ cut-offs and 45 cut-offs (rank 1)
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 03:44:30 pm
first 10 SA questions I thought I did really well maybe lost a few marks but the last one was horrendous.

whats the thought on A+ cut-offs and 45 cut-offs (rank 1)

Maybe like 96/110
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 03:45:28 pm
No idea, I did a bit better on this compared to the 2014/2013 ones on my first go, but that might be because of getting better at this stuff, most people seem to think itll be pretty low
Title: Re: Post Exam Discussion
Post by: Sine on October 30, 2015, 03:47:18 pm
Maybe like 96/110
for a 45?

No idea, I did a bit better on this compared to the 2014/2013 ones on my first go, but that might be because of getting better at this stuff, most people seem to think itll be pretty low
I actually think I did pretty well except for the last 5 marks and the 2 marks question for comparing the sediment(didn't really have enough info for 2 marks)  :(
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 03:49:15 pm
for a 45?
I actually think I did pretty well except for the last 5 marks and the 2 marks question for comparing the sediment(didn't really have enough info for 2 marks)  :(

In a hard exam then yes. Maybe a little higher like 99/110
Title: Re: Post Exam Discussion
Post by: thushan on October 30, 2015, 03:54:03 pm
Had a look at the exam. Wow that paper was hard - I'm pegging a cutoff of about 86-90/110.

About the last question - I think the evidence showed that humans originated in Africa. If early H. sapiens originated in say Asia - then they'd have been mating with Neanderthals. At some point, they would have migrated to Africa - with the Neanderthal DNA in them. However, since present day Africans do not have Neanderthal DNA, there's a contradiction.

If humans originated in Africa, then some would migrate and mate with Neanderthals elsewhere, but the ones in Africa remain in Africa, never mate with Neanderthals, and therefore have no Neanderthal DNA.
Title: Re: Post Exam Discussion
Post by: The Peasant on October 30, 2015, 04:01:13 pm
Had a look at the exam. Wow that paper was hard - I'm pegging a cutoff of about 86-90/110.

About the last question - I think the evidence showed that humans originated in Africa. If early H. sapiens originated in say Asia - then they'd have been mating with Neanderthals. At some point, they would have migrated to Africa - with the Neanderthal DNA in them. However, since present day Africans do not have Neanderthal DNA, there's a contradiction.

If humans originated in Africa, then some would migrate and mate with Neanderthals elsewhere, but the ones in Africa remain in Africa, never mate with Neanderthals, and therefore have no Neanderthal DNA.

Yeah, about the Out of Africa question, this was basically my line of thinking. Except for the fact that I didn't write my answer correctly.What really confused me was the fact that the Out of Africa hypothesis states that homo spaiens displaced other homonin  species without interbreeding, so I ended up writing a contradictory answer. :/
Title: Re: Post Exam Discussion
Post by: bridgetkelly123 on October 30, 2015, 04:12:24 pm
Cant remember what i wrote for differences but i remember writing macrophages for innate and for adaptive the question mentioned an established rough endoplasmic reticulum so i wrote about plasma cells, the exam has been scanned so ill check it now

Edit, yep its 8

Confused, how is it 8 amino acids?
Wasn't there a start codon (TAC), 7 amino acids and then a stop codon (ATT)
Title: Re: Post Exam Discussion
Post by: Biology24123 on October 30, 2015, 04:13:04 pm
Confused, how is it 8 amino acids?
Wasn't there a start codon (TAC), 7 amino acids and then a stop codon (ATT)

No amino acid for stop codon!!!
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 04:13:30 pm
Confused, how is it 8 amino acids?
Wasn't there a start codon (TAC), 7 amino acids and then a stop codon (ATT)

the start codon also adds an amino acid,making it 8
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 04:15:08 pm
also does thylakoid membrane = granum (for that light dependent reactions question)

i wouldnt think so, since a granum is a stack of thylakoids, not thylakoid membranes
Title: Re: Post Exam Discussion
Post by: Gromekk on October 30, 2015, 05:10:25 pm
honestly i have no idea anymore, i thought i knew but they all have too many names lol
Title: Re: Post Exam Discussion
Post by: Sine on October 30, 2015, 07:28:15 pm
what did you guys put down for the very last question?
Title: Re: Post Exam Discussion
Post by: mrturtle125 on October 31, 2015, 12:28:39 am
it is out of Africa theory but how the heck do you use the evidence to explain it?
Title: Re: Post Exam Discussion
Post by: Yacoubb on October 31, 2015, 08:20:56 am
what did you guys put down for the very last question?

From what I've looked at:

Route: Africa --> Middle East --> East Asia --> Australia
Timing: approximately 20 000 years (not 100% sure of this though)
Title: Re: Post Exam Discussion
Post by: StupidProdigy on October 31, 2015, 08:32:34 am
Just bringing my background knowledge into this, aboriginal australians existed around 45,000 years ago didn't they, so wouldn't it be more accurate to say withing the last 80,000 years?
Title: Re: Post Exam Discussion
Post by: Sine on October 31, 2015, 08:35:31 am
Just bringing my background knowledge into this, aboriginal australians existed around 45,000 years ago didn't they, so wouldn't it be more accurate to say withing the last 80,000 years?
I said 30,000 to 80,000 years ago (I had no idea what to do)
Title: Re: Post Exam Discussion
Post by: Impulse on November 06, 2015, 12:20:15 pm
Dw I couldnt remember the other so I put out of africa. Its probably multi regional now that I think about it ._.


It should be out of Africa. If it was multinational then African population would have Neanderthal DNA, which they don't.
Title: Re: Post Exam Discussion
Post by: djsbrks on November 12, 2015, 11:10:26 pm

It should be out of Africa. If it was multinational then African population would have Neanderthal DNA, which they don't.

Oh that's true, I guess it might just depend on our justification in the end if both answers are accepted :P
Title: Re: Post Exam Discussion
Post by: Biology24123 on December 10, 2015, 06:22:35 pm
I'll take anything above 40 as a study score. I made so many stupid mistakes on the exam so pretty sure I got 93-96/110. If the A+ cutoff is like 88 then that should be like a 42/43
Title: Re: Post Exam Discussion
Post by: _inspire45 on December 10, 2015, 07:28:00 pm
Yeah me too! People say this year's A+ cut off will be around 86-90/110 :(

Please advise ?
If my sac scores range between High A to Low-mid A+ (according to 2014 scaling) and i get around 94-97/110 for exam this year, do you guys think I can get anything above 40? :(

You all nervous? 3 days left...

Thanks!
Title: Re: Post Exam Discussion
Post by: Biology24123 on December 10, 2015, 07:35:04 pm
Yeah me too! People say this year's A+ cut off will be around 86-90/110 :(

Please advise ?
If my sac scores range between High A to Low-mid A+ (according to 2014 scaling) and i get around 94-97/110 for exam this year, do you guys think I can get anything above 40? :(

You all nervous? 3 days left...

Thanks!

That would definitely be above 40. Probably like 42. I'm predicting that I got 94/110. So dissapointed
Title: Re: Post Exam Discussion
Post by: Biology24123 on December 10, 2015, 07:39:22 pm
Anyone nervous for the results. I'll take anything above 40
Title: Re: Post Exam Discussion
Post by: _inspire45 on December 10, 2015, 07:42:54 pm
Same :(
Especially after I saw all the exam solutions...

I would be REALLY happy if i get 40+ :(
Title: Re: Post Exam Discussion
Post by: _inspire45 on December 10, 2015, 07:44:21 pm
I think you will get 40+ because 94/110 is definitely low-mid a+ and not many people did well on this year's exam
Title: Re: Post Exam Discussion
Post by: plants on December 10, 2015, 07:56:17 pm
I feel there's a lot of people disappointed with their bio exam performance (including me), so you're not alone. Stay strong guys :)
Title: Re: Post Exam Discussion
Post by: Biology24123 on December 10, 2015, 08:08:13 pm
I think you will get 40+ because 94/110 is definitely low-mid a+ and not many people did well on this year's exam

I bloody well hope so
Title: Re: Post Exam Discussion
Post by: Sine on December 11, 2015, 06:41:05 pm
I think everyone who did bio this year (and who were aiming highly) are super nervous as we have no exam of similar difficulty to compare it with.  😠

I really hope thushans prediction is on point ☺
Title: Re: Post Exam Discussion
Post by: Sine on December 14, 2015, 12:04:09 am
Predictions for cut-offs(assuming rank 1 or equivalent):

90/110 - 40SS/A+
95/110 - 45SS

Just to note A+ on the exam doesn't mean a 40 automatically.
Title: Re: Post Exam Discussion
Post by: Mikayla789 on December 14, 2015, 06:53:12 am
Just got text message, got 43, I'm so happy I though I stuffed the exam :DDDDDDDDDD