OCR Biology exam 17th may

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Hi all,

I think we should start an unofficial mark scheme. Anybody with experience of writing one? Happy to contribute a lot as I have a photographic memory :smile:

I am willing to help, but to be honest I forgotten quite a few of the questions already.

Reply 21

tj164

For the male and female chromosomes i put 'X and Y'. That determines what sex you are...I dont know if there is a proper word for that but whatever, only one mark ay

Reply 22

RosieBee37

Original post by m.zed28

Hey what did you guys get for the question about Ebola? Where the woman used a man's blood for treatment?

There is an article on the Independent that clearly the exam board got the question from as it is the same thing and pretty much has the answers in it. After reading it I'm not too sure that what I put was at all relevant but take a look at that for some ideas

Reply 23

RosieBee37

Original post by tj164

For the male and female chromosomes i put 'X and Y'. That determines what sex you are...I dont know if there is a proper word for that but whatever, only one mark ay

I put that too, in the specification and revision guide there isn't a name for them really, just a way of describing them (I'm not sure if that makes sense, but hopefully you understand what I mean)

Reply 24

m.zed28

Original post by RosieBee37

Hi can you please send me the link to that?

Reply 25

tj164

Original post by RosieBee37

I put that too, in the specification and revision guide there isn't a name for them really, just a way of describing them (I'm not sure if that makes sense, but hopefully you understand what I mean)

Yeah i get you, Somebody said something about Genotypes being included in the first question, The characteristics that you see are called phenotypes right?

Reply 26

Humaid00

Original post by GoldLeader

Hi all,

I think we should start an unofficial mark scheme. Anybody with experience of writing one? Happy to contribute a lot as I have a photographic memory :smile:

What did you get for the last question ? about the ancestors of A and B

Reply 27

HamzaIshtiaque

Original post by Humaid00

What did you get for the last question ? about the ancestors of A and B

I talked about how organism develop random mutations in their DNA, and since the DNA doesn't differ too much from the ancestors it suggests that enough time hasn't passed for the random mutations to alter the DNA.

Reply 28

tj164

Original post by Humaid00

What did you get for the last question ? about the ancestors of A and B

A- D and F
B- C and E

Think that was right, Confident which makes me feel like its wrong xD

Reply 29

Johnny Dorward

Lots of people seemed to struggle which means for the people who didn't boundaries should be lower.

Reply 30

AlexFagg

Get an unofficial mark scheme going please

Reply 31

Abbielucyrebecca

I put that aswell, but most people have put sex chromosomes lol

Reply 32

catlol

Original post by m.zed28

Hey what did you guys get for the question about Ebola? Where the woman used a man's blood for treatment?

In short, memory cells in his blood could be effective in fighting the virus in her blood. Ineffective due to the fact it's a virus and mutates quickly, chance of being effective is low, blood types could be different and ultimately cause her more problems, due to low levels of blood transferred unlikely to have much impact, cells likely to die.

(Don't know if any of that is right tbh)

Reply 33

m.zed28

Original post by catlol

Thanks. Haha it's a better answer than I gave.

Reply 34

fizzzatamuriii

Original post by HamzaIshtiaque

For the first 6 mark question regarding why twins are useful for scientist, I wrote the following points:
- I firstly described how twins are formed, so when a fertilised egg or zygote splits into 2 which continue to develop independently. I then linked this them both being genetically identical.
- The fact that they are genetically identical means that any changes must be due to their environment.
- This enables scientist to understand the affect of the environment on the human body and how it affects the characteristics.
- Some people may object to these experiments as it is unethical, reason being, there may be a risk towards those involved ( I was a bit confused for this point, let me know what you wrote for why people may consider it unethical).

What did you lot write for the question regarding the surgery that could reduce her chance of developing breast cancer?

I think the main thing u had to write about was epidemological studies and then relate it to the twins

Reply 35

Lilyhollowayd

Original post by haider96

i wrote hetrozygous by accident it was the pressure kicking in :colondollar:

i got this question wrong too, i completely blanked and wrote
'23rd pair xx and xy'

Reply 36

RosieBee37

Original post by tj164

Yeah i get you, Somebody said something about Genotypes being included in the first question, The characteristics that you see are called phenotypes right?