OCR F211/F212 AS Biology Retake 2016

I really doubt it will be 48 for an A, my teacher told me that they decide the grade boundaries looking at retakes from past years, so this year they will not be using a bell curve to decide the grade boundaries, as that would just be unfair. I reckon 44-46 for an A

Don't worry about how you've done though, all you can do is not worry about this and focus on the exams that you have coming up. Say you made a couple of silly mistakes in this paper, you can always pick up marks in F215 as there are so many marks and the grade boundaries are pretty low.

I don't see how this paper no matter if there were retakes or not could get to 48 for an A? I have never seen a grade boundary so high plus it was a very weird paper. Also I got DABE, for the cells I put pallisade and guard cells. For the heart I know i got it wrong I put aorta atrium and ventricle walls. For the part about the component of the membrane I put the hydrophobic tail which Im saying is wrong at the moment but I feel it is a component of the plasma membrane so input would be duly needed in that case. For the question about water up the moss in the exam I couldnt think of where it says that the only way the transpiration stream works if if there is a xylem so I went on about the tension from evaporation at the top etc. I will look in my textbook to see if that only works with the xylem Im not too sure. I got 117 micro metres for the thickness of the artery. Anaphase too. I got Z for the transmission and A was the scanning in my opinion because of the 3D image. Any other questions I will try to remember what I put. I feel I have lost 4 marks on the heart 4 marks on the water with the moss 2 marks on the DABE one and 1 mark on the phospholid bilayer one so far. So fair to say I am very worried at this point in time. I needed an A really to push myself to get the chance to get an A overall at A2.

It said "in" I underlined it.

I'd say 43 for an A.

I wrote 1.17 and didn't show any workings do you think they'd allow a mark

if you write a correct answer then have some parts of your answer that are incorrect, do you get marks deducted? thanks

if you write a correct answer then have some parts of your answer that are incorrect, do you get marks deducted? thanks

How can you make a mark scheme when noone actually has said what certain answers are. Like was the Amoeba question for membranes inside the cell and was it DABE or BADE or whatever else

I remembered all the Qs in mi head but not in the right order. Remembered the marks too to the best of my ability. The answers I wrote should be correct as they were what I wrote and I was confident on them and if I wasn't I looked them up just now before posting it m8 but we gotta work together to get all the answers ya feel?

Sorry mate I hadnt seem your markscheme. Replied to quickly it is very comprehensive.

(attempt at) UNOFFICIAL mark scheme for F211 2016 RESIT. Hope this helps y'all!
[Sorry I can't completely remember the order of the questions and this is by no means perfect so by all means ADD TO THIS as many questions could have multiple answers accepted and I could be wrong about some answers].

1. Amoeba don't need transport system - why? [2]
A) Have large SA:V. Diffusion is fast enough to supply it with nutrients needed. Only one cell thick so can penetrate easily.

2. What is the barrier to mineral ions in the membrane? [1]
A) Phospholipid bilayer

3. What feature of eukaryotic cell (might have been specific to the figure of the Amoeba?) not present in prokaryotic cell? [1]
A) Nucleus (may have been other answers acceptable?)

4. State two other things membranes can do? [2]
A) Hold components of metabolic pathways in place (e.g. carrier/channel proteins)
Act as binding sites for enzymes/hormones/etc
Regulate what goes in/out of cell
(There are multiple answers for this)

5. By what process does the Amoeba's vacuole mechanism thing get rid of water? [1]
A) Exocytosis/exopinocytosis (I don't know if they'll be cruel and only accept exopino or they might accept both; please be nice OCR!!)

6. What would happen if the Amoeba didn't have this vacuole mechanism thing? [1]
A) The cell would burst (might accept haemolyse/haemolysis? Someone on here has said that's specific to RBCs though so I'm not sure. Main thing is that you get 'burst' in there though. Hopefully they'd just ignore haemolysis if it's wrong and not completely discredit it. Only one mark tho so chill fam.)

7. Explain the data of number of times the vacuole expels water at different water potentials: -100kPa and -400kPa. [2]
A) At -100kPa water surrounding is less negative water potential in comparison to -400kPa which is more negative. Vacuole will expel more water at higher water potentials because more water enters the cell down water potential gradient (it is steeper). A mark will no doubt be awarded for comparing values. Several things you could say here for only 2 marks.

8. Give another feature of stem cells that makes them different to differentiated cells besides the fact that they can divide into a variety of different cells. [1]
A) ?????

9. What was the stage of mitosis on the insert. [1]
A) Anaphase

10. Describe the events occuring in mitosis up until the point used for answer in Q9^. [5]
A) Should be describing Prophase/Metaphase/Anaphase basically.
Prophase - DNA has already replicated in interphase. Chromatin condenses, supercoiling, thickening to form chromosomes as two sister chromatids attached at centromere.
Metaphase - chromosomes line up along spindle equator (attached at centromere). Each sister chromatid facing opposite poles of cell.
Anaphase - centriole spindle fibres shorten to divide centromeres, pulling each sister chromatid from their pair to opposite poles, led by the centromere.
(Could say a lot of stuff here for 5 marks, including QWC).

11. Describe the rest of the cell cycle aside from mitosis [3]
A) Interphase DNA replicates. Interphase includes growth 1 (G1), synthesis (S) and growth 2 (G2). In growth 1, the cell itself grows in size. In synthesis, the organelles and cell components are synthesised and in growth 2 the organelles grow in number too. (Hope I have that the right way around).

12. Microscope bit - table of magnification and resolution comparisons. Which one is TEM? [1]
A) Z (the one with magnification x500,000)

13. Two micrographs (figures a and b) of root hairs. Which figure was taken with an SEM? Justify your answer.
A) Should have been the top one (a). You could see the contours/3D shape of the hairs whereas you couldn't with the other one as it looked 2D (probably light microscope).

14. What is translocation? [3]
A) The transport of sugars/assimilates up and down the phloem in sieve tube elements from sources to sinks by mass flow from high hydrostatic pressure to low hydrostatic pressure. (Could've said several things here for the 3 marks.)

15. Moss Q - it contains no vascular tissue (no xylem or phloem). Suggest and explain how it's growth may be affected by this (or worded similarly to this). [2]
A) No vascular tissue means less structure and stability of plant, so won't grow as big. Less efficient transport of sugar and water so cells not as turgid/full of water for stability and structure. (Several things you could say. Feel free to add/correct!)

16. Name an adaptation that helps reduce water loss. [1]
Leaf curled/leaf hairs/thick waxy cuticle/densely packed mesophyll cells/less stomata/closed stomata/etc (so many things you could say for one mark).

18. Water transport gap fill. [4]
A) Cell wall
Endothelium/endothelial (the markers aren't going to be that picky dw they get your gist)
Plasmodesmata
Casparian strip


19. How can water be transported in moss from 'root-like structures' to leaves. [5]
(The mark scheme will prob put 'DO NOT CREDIT ref to cohesion-tension/adhesion' because remember the moss has no vascular tissues so it has NO XYLEM and NO PHLOEM. This was a right curveball Q I tell you.)
A) Root pressure - actively transported/pumps in nitrates/minerals. Lowers water potential of cells. Water follows by osmosis. Moves down water potential gradient by apoplast/symplast path into endothelial cells and is blocked by casparian strip so forced into symplast/vacuolar pathway. Moves to leaves through plant down water potential gradient by osmosis and is pushed through somewhat by root pressure.

20. What are two features of dicotyledonous leaves that wouldn't be present in the leaves of the moss? [2]
(If you didn't know what a dicot leaf is you'd be stressin so I'm sending you love cos that's a bit mean that they weren't more specific, but just remember that moss leaves are 1 cell thick).
A) Guard cells
Mesophyll cells

21. Calculate thickness of artery. [2]
A) 117 micrometres (116.6 recurring - round to nearest micrometre)

22. The heart sentences match up letters question [4]
A) Can't bloody remember so someone better fill this one in for me m8.

23. Transverse section of heart. Draw line. [1]
A) Only one mark so don't kys over it. Transverse is left to right though so should've been a line from left to right across heart. (Stress of the moment in the exam though so dw. I got this one wrong myself).

24. Labelling the transverse section. [3]
A) Since I got the first part wrong I don't want to say for sure.
I myself wrote atrium, septum, ventricle wall.

25. Why is staining needed? [2]
A) to make material visible, provide contrast, can identify components, see detail.

26. Functions of each in gaseous exchange [4]
Squamous epithelial cells -- short diffusion distance for gaseous exchange
Ciliated epithelial cells -- waft mucus with trapped pathogens to back of throat to be swallowed and destroyed by stomach acid
Goblet cells -- to secrete mucus
Smooth muscle -- to constrict airways

THIS MARK SCHEME IS NOT EXHAUSTIVE. There may be things I have missed (for some Qs I have explicitly said so) so I encourage you to add to this unofficial mark scheme and correct any bits if needed or add more detail.
If anything is wrong I apologise (e.g. Q mark values or even Qs in general)! I was begging for an unofficial M/S myself so now I've made one! Hope this helps! I'm outty!