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Cells, Exchange and Transport - PAST PAPER QUESTION HELP

http://www.ocr.org.uk/Images/175432-question-paper-unit-f211-01-cells-exchange-and-transport.pdf

How do you work out surface area to volume ratio in question 2a, help!

Thank you!

Reply 1

username1909405

Original post by rm_27

http://www.ocr.org.uk/Images/175432-question-paper-unit-f211-01-cells-exchange-and-transport.pdf

How do you work out surface area to volume ratio in question 2a, help!

Thank you!

Wouldn't it just be 6:10 after you cancel them???

Reply 2

username2488725

It would be 0.6:1

SA : V

600 : 1000

Divide both by 1000 as it is sa TO vol ratio

0.6:1

Reply 3

rm_27

Original post by CrazyFool229

It would be 0.6:1

SA : V

600 : 1000

Divide both by 1000 as it is sa TO vol ratio

0.6:1

Hey, thanks so much for answering!! I still don't really get it, do you mind doing steps on how you worked each thing out? I've got an exam tomorrow so all help is greatly appreciated!!

Reply 4

username2488725

No problem
So you read off the table the SURFACE AREA and the VOLUME. It tells you to read the values for the 10mm length I believe (On my phone, sorry).

Now, surface area TO volume ratio means you always divide the SURFACE AREA by the VOLUME. As it is a ratio you always get something like this

SA : 1

Notice how the second number is 1? This is because every time you DIVIDE BOTH SIDES by the VOLUME, and dividing the same number by itself always equals 1.

So here's an example

A cube has a SURFACE AREA of 10cm^2
VOLUME of 5cm^3

Setup the equation so it is like this

SURFACE AREA : VOLUME

Now the SA(surface area) is 10cm^2 and the volume is 5cm^3 so it will look like this

10 : 5

Now you DIVIDE BOTH SIDES BY THE VOLUME

So 10÷5 is 2
5÷5 is 1

SO THE FINAL ANSWER IS

2:1

I have an exam too on AQA Bio AS. Good luck!
Posted from TSR Mobile

Reply 5

rm_27

[QUOTE="CrazyFool229;65182197"]No problem
So you read off the table the SURFACE AREA and the VOLUME. It tells you to read the values for the 10mm length I believe (On my phone, sorry).

Now, surface area TO volume ratio means you always divide the SURFACE AREA by the VOLUME. As it is a ratio you always get something like this

SA : 1

Notice how the second number is 1? This is because every time you DIVIDE BOTH SIDES by the VOLUME, and dividing the same number by itself always equals 1.

So here's an example

A cube has a SURFACE AREA of 10cm^2
VOLUME of 5cm^3

Setup the equation so it is like this

SURFACE AREA : VOLUME

Now the SA(surface area) is 10cm^2 and the volume is 5cm^3 so it will look like this

10 : 5

Now you DIVIDE BOTH SIDES BY THE VOLUME

So 10÷5 is 2
5÷5 is 1

SO THE FINAL ANSWER IS

2:1

I have an exam too on AQA Bio AS. Good luck!
Posted from TSR Mobile[/QUOTE

THANK YOU!!! Good luck too!

(edited 7 years ago)

Reply 6

username2488725

Where did you get that answer from? The mark scheme says it is 0.6:1 because

600:1000

600 divided by 1000 = 0.6
1000 divided by 1000 = 1

Hence ratio is 0.6:1

Posted from TSR Mobile