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OCR F211/F212 AS Biology Retake 2016 watch

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    (Original post by rubyisdraked)
    (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!
    Quick question I thought the moss question is 4 marks. ( about the water)
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    (Original post by rubyisdraked)
    (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!
    For 10a would you have to talk about Anaphase as it says describe processes before your answer to 9a?
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    I disagree that the moss question about water was looking for the pathways of water. I remember the questions specifically asked for the 'mechanisms' which moved water up the plant which in the spec refers to cohesion, tension and adhesion.
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    (Original post by lucymay2)
    I disagree that the moss question about water was looking for the pathways of water. I remember the questions specifically asked for the 'mechanisms' which moved water up the plant which in the spec refers to cohesion, tension and adhesion.
    I agree because how does water go against force of gravity by symplast or apoplast pathway. I just put about cohesive forces and water potential gradient
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    I agree it has to be against gravity so maybe its cohesive and adhesive without a xylem
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    Here it is, the unofficial mark scheme for the F211 2016 retake paper (compiled by some lovely people)....what a weird paper....some really good questions but some really bad ones too....and oh god don't get me started on the last 4 maker on the transverse section of the heart...

    *disclaimer: we are in no way; shape or form, Darwin-level experts*
    Unofficial mark scheme F211 May 2016 Resitters
    Q1(a).why don't amoeba need a specialised gaseous exchange surface(2)
    • Large Surface area to volume ratio
    • Amoeba is single-celled so diffusion distance is fast as there are no deeper cells within organisms
    • Diffusion pathway is short.
    • Idea of it being adequate/ sufficient enough to supply oxygen and prevare enting build up of toxic waste products such as CO2
    Q1(b). State a organelle in fig…that isn't present in a prokaryotic cell(1)
    • Nucleus
    • Vacuole
    Q1(c).state component of the membrane that doesn't let through mineral ions(1)
    • Phospholipid (bilayer)
    • hydrophobic fatty acid tail
    Q1(d). State two functions of cell membranes in Amoeba(2)
    • Separates organelle components from cytoplasm - the membranes divide the cell into different compartments (compartmentalisation)
    • Increases the surface area
    • Reactions within organelles are more efficient
    • Can form vesicles to transport materials between different parts of the cell
    • Hold components of metabolic pathways in place
    • Site for receptors to attach
    Q1(e). How water move through cell(1)
    • Exocytosis
    Q1(f). What happens to the cell if the vacuole thing is not present(1)
    • Cell will burst
    Q1(g). Table question water potential(2)
    • At -100kpa the water potential of the surrounding has a higher water potential than the inside of the cell
    • Water travels by osmosis into the cell down a water potential gradient
    • However at -500kpa the water potential of the surrounding has a lower water potential than the inside of the cell so water does not travel by osmosis into the cell.
    • Therefore more water is filled and expelled at -100 than at -500
    Q2(a) how is a stem cell different to specialised cell (1)
    • can divide by mitosis
    How does water move through the roots and leaves in moss (4)
    • Active transport of mineral ion into the root hair cells
    • Decreases water potential
    • Water follows by osmosis
    • Root pressure - describe
    • Capillary action - adhesion - describe
    Q - Specimens can be viewed under light microscope. What are the advantages of staining?(1)
    • A lot of biological isn’t coloured
    • Adds contrast (this would be marking point on its own i think)
    • as different chemicals take up different amounts of stain
    • Distinguish between different parts of the cell
    Q what is meant by translocation (2)
    • It is mass flow of assimilates and sucrose up and down the phloem
    • Sucrose loaded at the source and unloaded at the sink
    Q fill in the gaps (4)
    • Cell walls
    • Plasmodesmata
    • Endodermis
    • Casparian Strip
    Q calculation q (2)
    • 117 um could be a range
    Q mitosis q
    1. Anaphase (1)
    1. Describe the events from the start of mitosis that took place to reach that stage shown in the image. (5)
    Mitosis is effectively a continuous process but consists of four stages.
    The first stage is called Prophase. In prophase the replicated chromosomes shorten and thicken (supercoil), and are now visible under a light microscope. The nuclear envelope breaks down and becomes invisible. An organelle called a centriole divides so that two daughter centrioles move to opposite ends (poles) of the cell to form the spindle (a structure made of protein threads/fibres).
    Following this, is Metaphase. In metaphase the replicated chromosomes (each with two sister chromatids) move to the centre of the spindle (the equator) and each becomes attached with their centromeres.
    The next stage is Anaphase, which is depicted in the image.
    1. Describe what happens in the rest of the cell cycle, excluding mitosis (3)
    Interphase:
    - S phase: DNA (genetic material) replicates
    - Growth phase (G1 & G2): cell growth, protein synthesis, organelles replicate (thus increase in numbers)

    Also:
    - ATP production is increased in interphase
    - DNA checked for any mutations

    Q microscopes
    1. What microscope shows the max. Magication of a TEM?(1)
    - Z
    1. ….(1)
    • Fig 3.a
    1. Why is it sem? (1)
    • 3D surface; magnification was lower
    Q what reduces water loss or something..(1) - densely packed spongy mesophyll cells and many others
    Q) how does air movement increase transpiration (2)
    • Air moves the water vapour away from the stomatal space
    • Increases the water vapour potential gradient
    • So more water evaporates from cells into stomatal space
    • More water is lost through transpiration
    Q. Define the term Tissue(2)
    • A tissue is a collection of cells that are specialised to work together to perform a common function.
    Q. Match the best statements about the ****ing heart from the other table in this table. Once has already been done for you (how sweet)....C. (4)
    • FABD??
    • FADE??
    • BADE?? Who knows
    Q. two cells present in a dicotyledonous leaf but not in the moss leaf excluding cells found in vascular tissue (2) -spongy mesophyll cells
    • Guard cells
    Q. Why can't moss leaves grow (2)
    • No xylem to transport water and minerals needed for photosynthesis
    • No phloem to transport assimilates such as sucrose
    Q the heart question (4)
    1. draw a horizontal line near the bottom of picture
    2. KLM - who knows
    1st one was the right ventricle 2nd one was septum3rd one was cardiac muscle
    Q functions of smooth muscle, cilia, goblet cells and squamous (4)
    • smooth muscle contracts to constrict the airway
    • Cilia moves in a synchronised way to waft mucus to the back of the throat
    • Goblet cells produce/secrete mucus to trap particles
    • Squamous epithelial are flattened cells which shorten the diffusion pathway for gases
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    (Original post by PeterMJP)
    For 10a would you have to talk about Anaphase as it says describe processes before your answer to 9a?
    It was a bit badly worded, but for the sake of how many marks it was yielding, I decided to include talking about anaphase just to cover my back. Depending on how much detail you went into about Prophase and Metaphase, you might not have needed to.
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    (Original post by rubyisdraked)
    (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!

    Ohh...looks like rubyisdraked got there first! browser was playing up...
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    (Original post by Realbigboi)
    I agree it has to be against gravity so maybe its cohesive and adhesive without a xylem
    The only point you couldn't raise is the water molecules attraction to the xylem walls.

    Everything else still stands: Water molecules are attracted to each other so are pulled up in a column, transpiration stream creates a tension/suction pulling water molecules up, then you have osmosis from a higher water potential (soil) to a lower in the leaves
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    For uses of internal membrane I put to maintain a concentration gradient using chemiosmosis as an example, I've seen it on a markscheme before and because it is eukaryote but Im slightly worried looking back on it
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    (Original post by lucymay2)
    I disagree that the moss question about water was looking for the pathways of water. I remember the questions specifically asked for the 'mechanisms' which moved water up the plant which in the spec refers to cohesion, tension and adhesion.
    Yeah and it said that even though it doesn't have an xylem and phloem, it still transports water in the same way
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    (Original post by AlexH123)
    The only point you couldn't raise is the water molecules attraction to the xylem walls.

    Everything else still stands: Water molecules are attracted to each other so are pulled up in a column, transpiration stream creates a tension/suction pulling water molecules up, then you have osmosis from a higher water potential (soil) to a lower in the leaves
    Water molecules form hydrogen bonds with cellulose molecules in cell walls - adhesion
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    (Original post by lucymay2)
    I disagree that the moss question about water was looking for the pathways of water. I remember the questions specifically asked for the 'mechanisms' which moved water up the plant which in the spec refers to cohesion, tension and adhesion.
    Innit it's strange, but osmosis is still a mechanism. Doubt there'll be credit for ref to chesion/tension/adhesion because there's no xylem, and moss aren't very tall so wouldn't require that. Igy though. Keep the discussion going!
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    (Original post by rubyisdraked)
    (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!
    Some suggestions/additions the question about cell cycle should accept ATP production and checking for errors as ive seen it in another similar q, the question on size of mosses i would add that it would be small as it has to have a large sa to volume ratio to transport water and minerals as it has no xylem/ phloem and finally I think the answer was BADE but there is a bit of a spit.
    Ps thank you so much im so stressing out this really helps to predict what i got
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    (Original post by DeclanKeeble)
    Here it is, the unofficial mark scheme for the F211 2016 retake paper (compiled by some lovely people)....what a weird paper....some really good questions but some really bad ones too....and oh god don't get me started on the last 4 maker on the transverse section of the heart...

    *disclaimer: we are in no way; shape or form, Darwin-level experts*
    Unofficial mark scheme F211 May 2016 Resitters
    Q1(a).why don't amoeba need a specialised gaseous exchange surface(2)
    • Large Surface area to volume ratio
    • Amoeba is single-celled so diffusion distance is fast as there are no deeper cells within organisms
    • Diffusion pathway is short.
    • Idea of it being adequate/ sufficient enough to supply oxygen and prevare enting build up of toxic waste products such as CO2
    Q1(b). State a organelle in fig…that isn't present in a prokaryotic cell(1)
    • Nucleus
    • Vacuole
    Q1(c).state component of the membrane that doesn't let through mineral ions(1)
    • Phospholipid (bilayer)
    • hydrophobic fatty acid tail
    Q1(d). State two functions of cell membranes in Amoeba(2)
    • Separates organelle components from cytoplasm - the membranes divide the cell into different compartments (compartmentalisation)
    • Increases the surface area
    • Reactions within organelles are more efficient
    • Can form vesicles to transport materials between different parts of the cell
    • Hold components of metabolic pathways in place
    • Site for receptors to attach
    Q1(e). How water move through cell(1)
    • Exocytosis
    Q1(f). What happens to the cell if the vacuole thing is not present(1)
    • Cell will burst
    Q1(g). Table question water potential(2)
    • At -100kpa the water potential of the surrounding has a higher water potential than the inside of the cell
    • Water travels by osmosis into the cell down a water potential gradient
    • However at -500kpa the water potential of the surrounding has a lower water potential than the inside of the cell so water does not travel by osmosis into the cell.
    • Therefore more water is filled and expelled at -100 than at -500
    Q2(a) how is a stem cell different to specialised cell (1)
    • can divide by mitosis
    How does water move through the roots and leaves in moss (4)
    • Active transport of mineral ion into the root hair cells
    • Decreases water potential
    • Water follows by osmosis
    • Root pressure - describe
    • Capillary action - adhesion - describe
    Q - Specimens can be viewed under light microscope. What are the advantages of staining?(1)
    • A lot of biological isn’t coloured
    • Adds contrast (this would be marking point on its own i think)
    • as different chemicals take up different amounts of stain
    • Distinguish between different parts of the cell
    Q what is meant by translocation (2)
    • It is mass flow of assimilates and sucrose up and down the phloem
    • Sucrose loaded at the source and unloaded at the sink
    Q fill in the gaps (4)
    • Cell walls
    • Plasmodesmata
    • Endodermis
    • Casparian Strip
    Q calculation q (2)
    • 117 um could be a range
    Q mitosis q
    1. Anaphase (1)
    1. Justification - chromatids at the end of each side (1)
    1. Describe the events from the start of mitosis that took place to reach that stage shown in the image. (5)
    Mitosis is effectively a continuous process but consists of four stages.
    The first stage is called Prophase. In prophase the replicated chromosomes shorten and thicken (supercoil), and are now visible under a light microscope. The nuclear envelope breaks down and becomes invisible. An organelle called a centriole divides so that two daughter centrioles move to opposite ends (poles) of the cell to form the spindle (a structure made of protein threads/fibres).
    Following this, is Metaphase. In metaphase the replicated chromosomes (each with two sister chromatids) move to the centre of the spindle (the equator) and each becomes attached with their centromeres.
    The next stage is Anaphase, which is depicted in the image.
    1. Describe what happens in the rest of the cell cycle, excluding mitosis (3)
    ATP production is also increased in interphase
    Q microscopes
    1. What microscope shows the max. Magication of a TEM?(1)
    - Z
    1. ….(1)
    • Fig 3.a
    1. Why is it sem? (1)
    • 3D surface; magnification was lower
    Q what reduces water loss or something..(1) - densely packed spongy mesophyll cells and many others
    Q) how does air movement increase transpiration (2)
    • Air moves the water vapour away from the stomatal space
    • Increases the water vapour potential gradient
    • So more water evaporates from cells into stomatal space
    • More water is lost through transpiration
    Q. Define the term Tissue(2)
    • A tissue is a collection of cells that are specialised to work together to perform a common function.
    Q. Match the best statements about the ****ing heart from the other table in this table. Once has already been done for you (how sweet)....C. (4)
    • FABD??
    • FADE??
    • BADE?? Who knows
    Q. two cells present in a dicotyledonous leaf but not in the moss leaf excluding cells found in vascular tissue (2) -spongy mesophyll cells
    • Guard cells
    Q. Why can't moss leaves grow (2)
    • No xylem to transport water and minerals needed for photosynthesis
    • No phloem to transport assimilates such as sucrose
    Q the heart question (4)
    1. draw a horizontal line near the bottom of picture
    2. KLM - who knows
    1st one was the right ventricle 2nd one was septum3rd one was cardiac muscle
    Q functions of smooth muscle, cilia, goblet cells and squamous (4)
    • smooth muscle contracts to constrict the airway
    • Cilia moves in a synchronised way to waft mucus to the back of the throat
    • Goblet cells produce/secrete mucus to trap particles
    • Squamous epithelial are flattened cells which shorten the diffusion pathway for gases
    I don't remember having to explain why it was anaphase for the mitosis question???
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    In the book it says that the mechanism is the cohesion theory
    • Thread Starter
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    nicoleemmak I don't think it did either
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    (Original post by nicoleemmak)
    I don't remember having to explain why it was anaphase for the mitosis question???

    Apologises...I was confused by that too...I don't think it did, somebody else contributed to that question
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    (Original post by DeclanKeeble)
    Ohh...looks like rubyisdraked got there first! browser was playing up...
    Yours is very good though and I forgot about that tissue question! The more the merrier I say!
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    (Original post by Lannew1)
    Some suggestions/additions the question about cell cycle should accept ATP production and checking for errors as ive seen it in another similar q, the question on size of mosses i would add that it would be small as it has to have a large sa to volume ratio to transport water and minerals as it has no xylem/ phloem and finally I think the answer was BADE but there is a bit of a spit.
    Ps thank you so much im so stressing out this really helps to predict what i got
    Thanks for your additions that's brill! And no prob, same here, man! Best of luck for results day, I hope you did great!
 
 
 
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