AS Biology (F211) - Jan 2013 Unofficial Mark Scheme Watch

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Rubbaduckzilla
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what grade is 44/45?
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SomePotential
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(Original post by Rubbaduckzilla)
what grade is 44/45?
It will be an A, unless the grade boundaries are really high.
Rubbaduckzilla
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(Original post by SomePotential)
It will be an A, unless the grade boundaries are really high.
thanks, even though its a guess that put a smile on my face ahh i hope so
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gabe_96
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Bacteria have polypeptide walls, not cellulose cell walls...
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Gotzz
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(Original post by SomePotential)
d. Why is it important that the electrical impulse is delayed? [2]

  • Allows the blood to flow into the ventricles from the atria;
  • Increasing the blood pressure in the ventricles;
  • Causing the aortic/pulmonary valves to open;
Do you not think it could also be that if the ventricles did not fully fill with blood, the atrioventricular valve would not shut, thus blood may backflow into the atria?
Cause that's what I put... :rolleyes:
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michelle_bucket
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does anyone know what is the mark out of 60 for grade A and B?not UMS.
thanksxxx
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Loiks94
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(Original post by Gotzz)
Do you not think it could also be that if the ventricles did not fully fill with blood, the atrioventricular valve would not shut, thus blood may backflow into the atria?
Cause that's what I put... :rolleyes:
Yeah that's full marks.
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fayled
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(Original post by SomePotential)
Yeast cells can divide by Binary Fission, but I don't think it's on our specification. I do recall seeing it on a previous mark scheme, so I decided to include it.



You might have to clarify that due to a lack of time scale you do not know the actual rate of bubble movement. But I don't know how harsh the actual markscheme will be. And yes, the [5] includes the QWC mark. So you'd need to make 4 points + 1 mark for QWC.



I'd presume they'd be similar to last years Jan exam, so something like;
A - 43
B - 38
C - 33
D - 29
E - 25

Full UMS would be around 55, based on the only grade boundary I could find for full UMS which was from the June 2010 series.

Last January I got 53 which was full UMS - so could be lower than this aswell.
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Blashnet
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51 according to this!
Hopefully i'll scrape the A
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BioGeek
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41-43 :/
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BioGeek
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Most yeasts reproduce asexually by mitosis I think mitosis is creditworthy as budding is when the bulge pinches off.
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Sam_1996
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What would i get on these?



With the xylem
How many marks would explaining
-to strengthen it
-dead cells so no internal cytoskeleton
-so it can withstand a high hydrostatic pressure
(/3)

With the tissue question(minus QWC mark)
-a group of cells working together to perform a particular function=tissue
-(lots of cilia in ciliate epitherlium to waft)
-a group of tissues working together to perform a function=organ
-in the lungs you have squamous and smooth muscle etc
(/4)

Cartilage:
-To keep the trachea open preventing collapsing
-if it collapses when smooth muscle constrict,gaseous exchange couldn't happen/not efficient enough
(/3)

Thanks
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Madihah101
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(Original post by SomePotential)
I tried to come up with the questions and answers from memory, so feel free to correct me where I'm wrong

1.
a. List three reasons why large animals, such as mammals, need a transport system. [3]
  • Small Surface Area:Volume ratio/Idea diffusion too slow;
  • High metabolic activity requires a lot of nutrients;
  • Cells near the surface can get the nutrients/nutrients used up by the time they reach cells deeper in the organism;
  • Transport system needed to supply cells deeper in the organism




b. Give the full name of the diagram used to measure electrical impulses. [1]

  • Electrocardiogram (trace);




c. Give the name of the labels A and B in the Insert. [2]
  • A - Sinoatrial Node/Pacemaker;
  • B - Atrioventricular Node;




d. Why is it important that the electrical impulse is delayed? [2]

  • Allows the blood to flow into the ventricles from the atria;
  • Increasing the blood pressure in the ventricles;
  • Causing the aortic/pulmonary valves to open;




e. Explain why the electrical impulse travels to the apex of the heart. [2]
  • To create the contraction of the ventricles from the bottom;
  • To push the blood up and out of the aorta/pulmonary artery;




2.
a. What is the name of the process of asexual reproduction in yeast cells? [1]
  • Budding/Binary Fission;




b. Outline the process of asexual reproduction in yeast cells. [2]
  • Mitosis occurs in the nucleus of the yeast cell;
  • A bulge develops on the side of the cell;
  • Cell membrane remains intact/cell organelles move the the bud;
  • bud splits from the yeast cell to produce a genetically identical daughter cell;




c. Ignoring the number of scars on the diagram, calculate the number of times the yeast cell could reproduce. [2]
  • Mark for working - Surface Area of Yeast Cell / Area of Scar - (4*3.14*1.52)/(3.14*0.52);
  • Mark for answer - 36;




d. Explain why the yeast cell might not be able to reproduce to its potential. [2]
  • Scars are circular;
  • So can not occupy total surface area/spaces between circular scars;
    or
  • Cell Cycle mainly in Interphase;
  • So yeast Cells may die before reproducing 36 times;




e. (QWC) Explain how cells are organised in a multicellular organism [5]
  • A tissue is a group of cells working together to perform a function;
  • Example of tissue/function;
  • An organ is a group of tissues working together to perform a function;
  • Example of organ/function;
  • An organ system is a group of organs working together to perform a life function;
  • Example of organ system/function;
  • AVP;
  • Use of 3 of the following words in correct context: tissue, organ, organ system, specialised...




3.
a. What is missing from the students table? [2]
  • Units of Measurement;
  • Used to calculate rate of bubble movement;
    or
  • Table of results;
  • Used to calculate mean rate.




b. Describe and explain the results on the table. [3]
  • As the number of leaves increase, the mean rate of bubble movement increases;
  • Use of figures from the table;
  • Increased number of stomata/surface area;
  • Increase in transpiration;




c. Explain why the students statement would effect the result and how he could improve the experiment. [6]
  • Different Size leaves result in difference number of stomata/larger surface area;
  • Use shoots with similar size leaves;
  • Wet leaves creates a humid microclimate/Reduces water potential gradient;
  • Wait for the leaves to dry;
  • Heat increases rate of evaporation/Light causes stomata to open;
  • Control the temperature/light intensity e.g. windowless room;




4.
a. Complete the gaps in the paragraph. [3]
  • Fluid Mosaic Model;
  • Active;
  • Lipids/Oxygen/Carbon Dioxide;
  • Carrier
b. Explain what the term cell signalling means. [1]
  • Cell Signalling is a process that leads to communication and coordination between cells;
  • Example of cell signalling;




c. (QWC) Explain the process of cell signalling. [4]
  • Glycoproteins/Glycolipids in plasma membrane;
  • Receptor;
  • Cell Signalling Molecule/Example e.g. hormones/enzymes;
  • Bind to receptor;
  • Which has a complimentary shape;
  • Use 3 of the following terms in correct context: Receptor, Glycolipid, Glycoprotein, Complimentary shape...




5.
a. Which organelles are present in a plant cell, animal cell and bacterial cell? [4]

Table































Cell Feature
Plant Cell
Animal Cell
Bacterial Cell
Chloroplast
Present
Absent
Absent
Cellulose Cell Wall
Present
Absent
Absent
Centrioles
Absent
Present
Absent
Ribosomes
Present
Present
Present

1 mark for each correct row.



b. Which test tubes contained the following organelles? [4]
  • Nuclei - 1;
  • Ribosomes - 4
  • Mitochondria - 2
  • Lysosomes - 2




c. Which organelle from above is the smallest? [1]
  • Ribosome;




6.
a. Explain the importance of lignin. [3]
  • Waterproofs xylem vessel wall/Stops water loss from Xylem wall;
  • Creates pits to allow water transport from Xylem vessel to other tissues;
  • Pattern in Lignin allows it to be flexible;
  • Supports the Xylem vessel/stops it from collapsing;




b. Explain the importance of cartilage. [3]
  • C - rings to allow movement of food in trachea
  • Gives support to the trachea;
  • Stops it from collapsing during inhalation;
  • Allows the neck to bend without damaging trachea;




c. Comment on the data about surface area and volume of the body/lungs. [3]
  • Small Surface Area:Volume ratio
  • Insufficient for bodys need;
  • Need a specialised exchange surface;
  • Such as alveoli;
  • Which has a large surface area for more gaseous exchange;


Please note, these are only some of a wide range of answer. If you're answer isn't on here, it could still be correct.
Predicted grade boundaries?
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SomePotential
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#34
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(Original post by fayled)
Last January I got 53 which was full UMS - so could be lower than this aswell.
That's very good to know ^^

(Original post by Blashnet)
51 according to this!
Hopefully i'll scrape the A
51 is a comfortable A, irregardless of grade boundaries. As seen above, 53 was full UMS last January.

(Original post by BioGeek)
Most yeasts reproduce asexually by mitosis I think mitosis is creditworthy as budding is when the bulge pinches off.
Mitosis occurs during Budding, so it might be creditworthy. My Biology teacher said it was budding, as part b asks you to outline the process of asexual reproduction of yeast cells. As most people described budding here, it made sense to put budding to part a. You'd probably get the mark for mitosis or binary fission.
BioGeek
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(Original post by SomePotential)
That's very good to know ^^



51 is a comfortable A, irregardless of grade boundaries. As seen above, 53 was full UMS last January.



Mitosis occurs during Budding, so it might be creditworthy. My Biology teacher said it was budding, as part b asks you to outline the process of asexual reproduction of yeast cells. As most people described budding here, it made sense to put budding to part a. You'd probably get the mark for mitosis or binary fission.

Can you put a poll in saying if they found the exam hard or not pleasE?
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waheed786
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3.a. What is missing from the students table? [2]
would i get any marks if i wrote;
-Distance moved by bubble through the potometer.
-And time taken for bubble to move that distance.

I was panicking in the exam so wrote anything down, i know this may be nil because they gave the rate of the bubble, but that doesn't show us the exact distance moved by bubble and time taken for bubble to move in potometer, if you get what i mean??
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reneetaylor
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(Original post by SomePotential)
Yeast cells can divide by Binary Fission, but I don't think it's on our specification. I do recall seeing it on a previous mark scheme, so I decided to include it.



You might have to clarify that due to a lack of time scale you do not know the actual rate of bubble movement. But I don't know how harsh the actual markscheme will be. And yes, the [5] includes the QWC mark. So you'd need to make 4 points + 1 mark for QWC.



I'd presume they'd be similar to last years Jan exam, so something like;
A - 43
B - 38
C - 33
D - 29
E - 25

Full UMS would be around 55, based on the only grade boundary I could find for full UMS which was from the June 2010 series.
If so, then I'm laughing.
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BenHay3108
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Thank you so much for writing this out, it's put my Mind at rest as we've got pretty similar answers. hopefully ill get an A. I felt the paper was very obscure and didn't ask much on the key topics of the syllabus, for example lung tissues, nothing on haemoglobin and instead very open ended question like how is a multicellular organism organised.
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SomePotential
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(Original post by BioGeek)
Can you put a poll in saying if they found the exam hard or not pleasE?
Such a thread already exists here:
http://www.thestudentroom.co.uk/show....php?t=2222340
R1C3W1N3
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(Original post by rainingdewdrops)
thanks a lot for this! but on the cartilage question isn't it the esophagus that does the swallowing of the food? also for 6a could you also include that it allows for adhesion because water is attracted to it?
finally im not sure if this is right but for 2d could you say because mutations were found in the checking process causing the cycle to start again?
thanks again!! this is very much appreciated
Heyyy, I put mutattions maybe a reason the cell does not reach maximum daughter cell number... let's hope it's right
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