OCR Biology F211 resit - 16th May

how much marks was the last question for?

I don't know whether this has already been said but a lot of people have been mentioning they didn't know the answer to how you measure the uptake of oxygen with a spirometer...

Basically, you measure the amount of air lost, as when your body takes up oxygen, it releases CO2 which is then absorbed by the soda lime. So there will be less air in the chamber, the more oxygen is taken up.

I personally loved the spirometer question. :smile:

Reply 362

Rup

6

Original post by jamu92

how much marks was the last question for?

if u r talking abt how sucrose loaded in phloem question, it was 4 marks, and i loved it!

Reply 363

Groat

13

Original post by kazx

I don't know whether this has already been said but a lot of people have been mentioning they didn't know the answer to how you measure the uptake of oxygen with a spirometer...

Basically, you measure the amount of air lost, as when your body takes up oxygen, it releases CO2 which is then absorbed by the soda lime. So there will be less air in the chamber, the more oxygen is taken up.

I personally loved the spirometer question. :smile:

I think a lot of people may have missed the mark in saying that carbon dioxide exhaled = oxygen inhaled yet the carbon dioxide is absorbed by the soda lime. Therefore the volume lost in the air chamber is the oxygen uptake. :eek:

Reply 364

BradfordCityJoss

Original post by Groat

I think a lot of people may have missed the mark in saying that carbon dioxide exhaled = oxygen inhaled yet the carbon dioxide is absorbed by the soda lime. Therefore the volume lost in the air chamber is the oxygen uptake. :eek:

True this.

Reply 365

Chakula

6

Original post by jndk109

the one about meristem cells i also put pericycle and cambium

i wrote exactly the same :smile:

Reply 366

sixthformer

Original post by Amodeus

-Increases contrast so you can identify the cells more easily
-See organelles inside the cell (eg nucleus)
-Lets you see the chromosomes, so you can follow the stages of mitosis

plant cells are mostly water so trans parent
staining helps therefore to be able to see the contents of the cell
it also adds contrast

Reply 367

sixthformer

Original post by lolo_uk

im thinkin 40ish for an A

this paper had stupid questions on it tbh.

i think it will be 44/60 for an A

even so, i doubt i'll get that

Reply 368

sixthformer

Original post by mmsalvatore

Thats what I did. But the book says Meristems are found at the roots and shoot tips, and in ring of tissues in the stem or trunk.
That was a 2 Mark question, right?

i feel so upset

i wrote they are founds in the stem, and in the roots

Reply 369

BradfordCityJoss

Original post by sixthformer

i feel so upset

i wrote they are founds in the stem, and in the roots

I put root (tip) cells and in-between xylem and phloem in the stem. I don't know whether or not you need to put Cambium which is right ofc, but there is definitely meristematic tissue in root tip cells and between xylem and phloem in the stem.

It really depends on the mark scheme.

Reply 370

Jade1234

did anyone else miss read the question about the left ventricle being thicker?! i didnt realise i was meant to compare it to the atrium!

Reply 371

dylanmitchard

Original post by Jade1234

did anyone else miss read the question about the left ventricle being thicker?! i didnt realise i was meant to compare it to the atrium!

It was compared to the atrium, i put that the left ventricle had to pump the blood all round the body compared to the atrium just to the ventricle

Reply 372

Jade1234

Original post by dylanmitchard

It was compared to the atrium, i put that the left ventricle had to pump the blood all round the body compared to the atrium just to the ventricle

well hopefully i got some marks for it, as i said that too

Reply 373

lolo_uk

Original post by Chakula

i wrote exactly the same :smile:

mine was worse cuz i put cell wall and root then crossed the root out :angry:

Reply 374

lolo_uk

Original post by sixthformer

this paper had stupid questions on it tbh.

i think it will be 44/60 for an A

even so, i doubt i'll get that

same it was a hard paper and stupid questions :frown:

Reply 375

lolo_uk

Original post by HazyMonsoon

Aren't water and ions transported by (facilitated) diffusion? :O

ya ur right i got it wrong :confused:

Reply 376

_Jasmine

5

Original post by kazx

I don't know whether this has already been said but a lot of people have been mentioning they didn't know the answer to how you measure the uptake of oxygen with a spirometer...

Basically, you measure the amount of air lost, as when your body takes up oxygen, it releases CO2 which is then absorbed by the soda lime. So there will be less air in the chamber, the more oxygen is taken up.

I personally loved the spirometer question. :smile:

That's not what the question about oxygen uptake asked. It asked to explain how to use the TRACE not the spirometer, so you'd write that you have to draw a slope against the downwards trace and work out oxygen uptake by working out the slope.

Reply 377

Groat

13

Original post by _Jasmine

That's not what the question about oxygen uptake asked. It asked to explain how to use the TRACE not the spirometer, so you'd write that you have to draw a slope against the downwards trace and work out oxygen uptake by working out the slope.

Yes, but you've just made an assumption out of nowhere that the difference in peaks of the first breath and the last breath is the oxygen uptake. Therefore, it made sense to say that oxygen intake = carbon dioxide exhaled, yet as the carbon dioxide is absorbed, this is also equals the reduction in the volume of air.

Reply 378

_Jasmine

5

Original post by Groat

Yes, but you've just made an assumption out of nowhere that the difference in peaks of the first breath and the last breath is the oxygen uptake. Therefore, it made sense to say that oxygen intake = carbon dioxide exhaled, yet as the carbon dioxide is absorbed, this is also equals the reduction in the volume of air.