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IGCSE Edexcel Biology May 17th 2016

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Original post by HKHASSAN
For the CORMS question in Paper 1B I thought it was like this:

C: Have a range of different temperatures (eg 15, 20, 25, 30, 35, 40oC)
O: Ensure all eggs are taken from the same animal
R: Repeat the experiment 5 times for each temperature
M: Count how many out of the five eggs survived the nutrient solution at whatever temperature they were at
S: Keep the volume of nutrient solution consistent with every experiment and keep the number of eggs in each test tube/petri dish consistent.

Conclusive statement: The best storage temperature will be the one where, on average, most eggs survive.

Would I get the 6 marks?


I did the same thing except S. I said the pH in the test tube should be constant as if it is alkali or acidic then eggs will die. You would probably get 6 tho

*edit* I also said taken from the same species of mammal rather than the exact same mammal *edit*
I've tried to compile a provisional mark scheme here If anyone wants to have a look or add to it go ahead.

Please comment more answers on it as I'm sure I have missed questions from today.

Great Work Guys
Original post by gameofno
No clue :/ some people are saying lens


Praying it's cornea, I guessed on that question lmao
Original post by george_c00per
Praying it's cornea, I guessed on that question lmao


Sclera

Optic nerve

Lens

These seem the most popular answers for each box respectively.

Provision Mark Scheme:

http://www.thestudentroom.co.uk/showthread.php?t=4092245
Original post by HKHASSAN
For the CORMS question in Paper 1B I thought it was like this:

C: Have a range of different temperatures (eg 15, 20, 25, 30, 35, 40oC)
O: Ensure all eggs are taken from the same animal
R: Repeat the experiment 5 times for each temperature
M: Count how many out of the five eggs survived the nutrient solution at whatever temperature they were at
S: Keep the volume of nutrient solution consistent with every experiment and keep the number of eggs in each test tube/petri dish consistent.

Conclusive statement: The best storage temperature will be the one where, on average, most eggs survive.

Would I get the 6 marks?


Hopefully, I wrote near to identical to you, except I said "put the eggs and the nutrient solution in a test tube, then attach it to a pipe leading to limewater and measure which temp turns it milky the fastest, proving there are more alive eggs which are respiring". I added this as a lot of past papers I've done expected to refer to an experiment which we've done in Biology, and I think we have done that before.
Original post by JackCollard
Sclera

Optic nerve

Lens

These seem the most popular answers for each box respectively.

Provision Mark Scheme:

http://www.thestudentroom.co.uk/showthread.php?t=4092245


shittttt, i put conjunctivia (is that even a thing) instead of sclera and cornea instead of lens. i didn't do any eye revision so Im happy that I got 3/5 correct about eyes
Original post by HKHASSAN
For the CORMS question in Paper 1B I thought it was like this:

C: Have a range of different temperatures (eg 15, 20, 25, 30, 35, 40oC)
O: Ensure all eggs are taken from the same animal
R: Repeat the experiment 5 times for each temperature
M: Count how many out of the five eggs survived the nutrient solution at whatever temperature they were at
S: Keep the volume of nutrient solution consistent with every experiment and keep the number of eggs in each test tube/petri dish consistent.

Conclusive statement: The best storage temperature will be the one where, on average, most eggs survive.

Would I get the 6 marks?


Probably. I would think the following might be the mark scheme:

C: Range of temperatures, including below freezing (usually egg cells are frozen and stored at -100 degrees C or below, so they may be picky)
O: Same species/same organism
R: Use large sample size/repeat
M1: Wait at least a week
M2: Count number of egg cells that are still alive at each temperature
S: Content of nutrient solution/volume of nutrient solution/crowdedness/gases in surrounding air/light intensity
ok here is what i got for these questions:
The nerve question asked for the time the impulse took, which was 0.0075s - (90cm/12000cm = 0.0075)
The anomalous kid was thomas - his heart rate just before was lower than resting heart rate.
Reason for increase heart rate just before was adrenaline, fight or flight increases heart rate etc.
Lots for the two conditions kept the same, I put temperature and type of exercise i.e each kid ran the same distance
A greenhouse gas could have been CFC or water vapour, it asked for ones other than the ones mentioned
The hard one for the was the scelera, I put scelera then crossed it out and put cornea...****
Percentage decrease of CO2 was around 16% I think, change over original x100
I not sure whether they'll allow length of activity because it was mentioned in the question. Age of children and Type of exercise were probably safer choices.
Original post by Year11Struggles
What do you think that two marks were for?
i said Adrenaline is produced by the adrenal glands to prepare for exercise. This increase the heart rate.
Do you think that is two marks?
Also was the anomaly Thomas?


anomaly was thomas
i dint specifically say adrenaline but i wrote the body is preparing you so increases the heart rate in anticipation. Do you think this is right?
carbon dioxide a greenhouse gas?
Original post by george_c00per
shittttt, i put conjunctivia (is that even a thing) instead of sclera and cornea instead of lens. i didn't do any eye revision so Im happy that I got 3/5 correct about eyes


Conjunctiva could be right, lots of people have said that. The mark scheme might be 'Sclera / Conjunctiva'.Keeps your hopes up son! :,)
Original post by Job738338
anomaly was thomas
i dint specifically say adrenaline but i wrote the body is preparing you so increases the heart rate in anticipation. Do you think this is right?


I think Adrenaline was the main idea they were looking for here.
Didn't they specify the units in the calculation to cm's/second
This off google guys :biggrin:
This process is the fundamental cause of the greenhouse effect. The primary greenhouse gases in Earth's atmosphere are water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

Imagine there are a few others
Original post by Callum122
Didn't they specify the units in the calculation to cm's/second


yeh i think so as well
Original post by Job738338
yeh i think so as well

Yeah it said "What is the speed, in cm's/second" Didn't it? In which case it was 0.75
Guys this is exactly what I wrote for the investigation can somebody tell me what mark I can score :
Three groups of egg cells obtained from the same female consisting of 5 each are organized All the cells are grown in a nutrient solution with the same nutrients and same amount of oxygen and same volume of solution.one group is kept at 20 c ,another at. 30 c and third at 40c.
They are left for a week and then with the help of microscope the number of egg cells that survived is counted. And the experiment is repeated.
You have to convert it to metres like in physics when you use the speed equation so 0.0075m/s is right. If you left it as cm it would be cm/s
Exam was hard.....

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