OCR Biology A Exam Thread (Breadth - May 26, 2016 and Depth - June 7, 2016)

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This depth paper was weird. How do you think the Chem depth paper would be? Tbh I don't know how to revise for that now.

After seeing this paper, Chemistry worries me a bit. I am expecting high marks on electrophilic addition, nucleophilic addition and free-radical substitiution. In addition, more questions about the intermolecular forces and covalent, ionic bonding properties. Average bond enthalpy or Hess'Law may reappear again. Definitelt oxidising alcohol will come up and alkanes/alkenes or stereoisomers etc.

Reply 1521

Firenze26

Original post by sen99

For the T-test, I put 7 as the degrees of freedom because I thought that since there are two groups of data it would be an unpaired t-test so the d.o.f would be (n1-n2)-1 therefore (4+4)-1=7. Is this right?

Dang it, everyone's getting like different numbers than me.

I'm not sure if it's right but I got 6 because, in my book, it said (N1-1)+(N2-1)=degrees of freedom so I got 6

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Reply 1522

oni176

Original post by Tarlius

Also please answer guys, and please don't take the piss because I find biology so hard, I'll be dropping it and keep maths physics and art but I just cant stand it so.. I think on the first paper I may have gotten around 30 marks give or take 2, and about 40 give or take two on this one? Is that worthy of just any grade asides a U do you think?

Many thanks

D for definite in my opinion, or even a C.

(edited 7 years ago)

Reply 1523

rachelemi

[QUOTE=Tarlius;65539627]Also please answer guys, and please don't take the piss because I find biology so hard, I'll be dropping it and keep maths physics and art but I just cant stand it so.. I think on the first paper I may have gotten around 30 marks give or take 2, and about 40 give or take two on this one? Is that worthy of just any grade asides a U do you think?

Many thanks

If an A is 63% like last year then mostly you'll be on the B/C boundary depending if it's 10% difference between each grade like normal

Reply 1524

Cherx

Original post by oni176

So they would be less likely to have application questions? Urgh so worrying. But thank you for the predications!

Reply 1525

4nonymous

Original post by Firenze26

Dang it, everyone's getting like different numbers than me.

I'm not sure if it's right but I got 6 because, in my book, it said (N1-1)+(N2-1)=degrees of freedom so I got 6

Posted from TSR Mobile

Original post by sen99

That's for t-test, this wasn't t-test. Also the question told you what you had to do to get the degrees of freedom. It said DoF=number of categories -1. so it was 4-1=3

Reply 1526

oni176

Original post by Cherx

So they would be less likely to have application questions? Urgh so worrying. But thank you for the predications!

Biology involves application questions but Chemistry is purely on knowledge. Oxidation of alcohol is an example of practical with reflux and distillation process. They might put synthesis thing + titration as examples of practical along with it.

Reply 1527

wojiaoshakira

Original post by Tarlius

has to be a D as a D is 50%. a C is usually around 60% but judging that this is a new spec a C will be 50 something% so 70/140 would be a D. as long as your mark overall is 70 something you are safe

Reply 1528

Cherx

Original post by oni176

Ah okay. I'm gonna try to do a couple of F322 papers tonight. There's the stuff about green house, carbon storatge/capture and catalytic converter in the 2009 paper. Is that all in the old spec? I felt that the past papers for bio were pretty useless for our spec so many stuff was not in our spec.

Reply 1529

oni176

Original post by Cherx

Some info about the carbon cycle we don't need to know other than knowing the radical for ozone layer and chlorofluorocarbons as well as the protocol.

Reply 1530

Cherx

Original post by oni176

Some info about the carbon cycle we don't need to know other than knowing the radical for ozone layer and chlorofluorocarbons as well as the protocol.

I was planning on memorising the set answers but I guess that's just wasting my time if it's unlikely to be in the paper. For example this question 'Outline the stages that take place in a catalytic converter to allow CO to react with NO'

One of the points was 'weakening of bonds OR lowers activation energy' there was something in infrared radition about absorbing atmoshpheric gases does that link to this question?

Reply 1531

FrustratedHorse

Original post by Firenze26

Dang it, everyone's getting like different numbers than me.

I'm not sure if it's right but I got 6 because, in my book, it said (N1-1)+(N2-1)=degrees of freedom so I got 6

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Bro,I know exactly where you're coming from and I did the same thing in the exam using the exact same justification. Afterwards however, my friend kicked some sense into me- there were 4 categories/data sets (Prophase, anaphase, metaphase and telophase) unlike the 2 data sets used in the example in the text book. So in this situation, I think it should be something like (N1-1)+(N2-1)+(N3-1)+(N4-1). This is the same as 4(2-1) which is equal to 4. So tbh, as far as I understand, there were only 4 degrees of freedom in the exam so I got that question wrong.

Either way,I talked with my teacher and she said that so long as I compare my value at 0.05 significance level, I should end up with at least 1 mark. Well, hopefully it works that way :smile:

.Imo, this exam was pretty difficult and considering not every school is taking these AS breadth and depth exams (because they intend to just do the real A2's), I don't mind so long as I get a B (or above) overall so that I can have strong ground to beg my biology teacher to predict me an A for A2.Dw guys, it's time to make like a student and pray for low grade boundaries :crossedf:

Reply 1532

Cherx

Forget that . I'm hoping that I could at least scrape a D or maybe even an E :lol:

Reply 1533

Jitesh

Original post by wojiaoshakira

has to be a D as a D is 50%. a C is usually around 60% but judging that this is a new spec a C will be 50 something% so 70/140 would be a D. as long as your mark overall is 70 something you are safe

on the old spec it was like 70% for an A so might be even a tad bit lower

Reply 1534

nwmyname

http://www.thestudentroom.co.uk/showthread.php?p=65536755&highlight=

Grade boundaries (predicted) are on my thread.

Reply 1535

obiageli1993

how are you able to predict them, how accurate is this?

Original post by nwmyname

http://www.thestudentroom.co.uk/showthread.php?p=65536755&highlight=

Grade boundaries (predicted) are on my thread.

Reply 1536

11...

what did you guys put for the question where it asks for two modifications for the experiment. I put calculate mean to help identify anomalies, and I also put carry out the experiment between 30 -40% to get a more accurate representation of the optimum temperature. Not sure if it is right though.

Reply 1537

11...

for the 6 marker on enzymes and temperature. I wrote about the lock and key model and induced fit model. and talked about complementary.,.. . induced fit is the modern model which suggests that the enzyme changes shape slightly..
and I put rate of reaction increase as temperature increases as the enzyme and substrate have more kinetic energy, resulting in more frequent collisions and more successful collisions. But at temperatures much higher the optimum, the hydrogen bonds and ionic bonds vibrate and break. this changes the shape of the active site and the substrate no longer fits in to the active site. the enzyme denatures. the tertiary structure is altered. lipase cant break down lipids into fatty acids and glycerol.

Reply 1538

jbman690

lots of easy content questions, but quite a bit of sheggy application questions. i think i did alright, could have been worse though...

Reply 1539

nwmyname

Original post by obiageli1993

how are you able to predict them, how accurate is this?

This is based on previous years' UMS percentage on more difficult F212 paper out of 100. This is also consistently close enough with the F211 paper.

I had to compensate with the lack of coursework and other factors that I outlined on my post and made approximations.

This is also inline with student feedback and Ofqual + OCR information given which states that grade boundaries should be similar to last years if both students found it similarly hard.