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  1. R

    AS Biology P1 MCQs Preparation Thread

    The graph in which volume of blood in left ventricle is on y-axis and time is on x-axis. (for one cardiac cycle) I Hope it does not come. ECG and pressure graphs are enough!:p
  2. R

    AS Biology P1 MCQs Preparation Thread

    Can Someone explain to me how Water Potential, Solute Potential and Pressure Potential are related?? (i mean which equation relates them??) :)
  3. R

    AS Biology P1 MCQs Preparation Thread

    What about the graph for change in volume of blood in left ventricle during one cardiac cycle. Could that come too?
  4. R

    AS Biology P1 MCQs Preparation Thread

    the field of view is circular so you will use the formula for area of a circle which is = pi x raidus^2. To find this out, you need to calculate the radius. From the figure, 40 divisions on eyepiece graticule are equal to 0.1 mm or 100 um. As the radius is equal to 50 divisions, so the actual...
  5. R

    AS Biology P1 MCQs Preparation Thread

    the Answer is 12^2 = 144 (option C). Dipeptide means that there are 2 amino acids in the chain and there are 12 different types of amino acids available to be part of the dipeptide. Therefore, 2 becomes the power of 12, giving the answer 144. If 20 different amino acids were available for a...
  6. R

    AS Biology P1 MCQs Preparation Thread

    There is a fine line between growth of cells and growth of tissues. Mitosis causes growth of tissues by increasing cell numbers; it does not cause the growth of a cell itself! :) It's important to understand that mitosis causes growth and repair of tissues, not growth and repair of cells!
  7. R

    AS Biology P1 MCQs Preparation Thread

    By internal membranes it does not refer to double membranes. Do not confuse inner membranes with internal membranes! :) Only mitochondria and chloroplasts have internal membranes (cristae and thylakoids respectively). Nucleus has a double membrane but no internal membranes.
  8. R

    AS Biology P1 MCQs Preparation Thread

    Malaria is caused by plasmodia (plasmodium is the parasite), which are carried by female Anopheles mosquitoes. These mosquitoes survive and breed in a hot enivironment with higher temperatures (such as the tropics). Also, the malarial parasite (plasmodium) requires temperatures above 20 degree...
  9. R

    AS Biology P1 MCQs Preparation Thread

    The Answer is C. Solute potential is the same as water potential, so a low solute potential means a low water potential. The phloem sap has low water potential, since it contains a significant quantity of assimilates such as sucrose and amino acids (phloem transports assimilates). Also, the cell...
  10. R

    AS Biology P1 MCQs Preparation Thread

    Hmmm, then to find volume of oxygen absorbed in a given time simply multiply the volume of air absorbed in the given time with .20, since there is 20% oxygen in air. :)
  11. R

    AS Biology P1 MCQs Preparation Thread

    i don't know, which graph? I mean what would be the axis of the graph?
  12. R

    AS Biology P1 MCQs Preparation Thread

    volume of air absorbed into 0.21% i guess, but that gives you the volume of oxygen inhaled during one breath. :unsure:
  13. R

    AS Biology P1 MCQs Preparation Thread

    For Q17, red blood cells are animal cells and therefore, do not have a cell wall. Cell wall is present in plant cells and withstands the turgor pressure to make the plant cell turgid. In red blood cells, there is no cell wall to withstand the pressure due to the water that moves in, so the cell...
  14. R

    AS Biology P1 MCQs Preparation Thread

    One peak curve/parabola, represents one breath on a graph (with volume of air in lungs on y-axis and time on x-axis.) So you should know that the number of peak curves is equal to the number of breaths and breathing rate is equal to the no. of breaths per unit time (breaths per second or per...
  15. R

    AS Biology P1 MCQs Preparation Thread

    Yes the elastic fibres/elastin, do have the same function in blood vessels. You may find the video at the following link helpful in understanding the DNA experiment: http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter14/meselson_and_stahl_experiment.html :)
  16. R

    AS Biology P1 MCQs Preparation Thread

    I guess not, since it depends upon the water potential inside the mitochondria, which must be about the same as that of the solution in which they are placed. The correct option is therefore C as the solution prevents (significant) net movement of water into or out of the mitochondria...
  17. R

    AS Biology P1 MCQs Preparation Thread

    Translation has to happen before condensation, since translation is the pairing of codon (on mRNA) and anticodon (on tRNA) whereas condensation is the formation of peptide bond between two amino acids that are brought to the ribosome by the tRNA (the amino acids are attached to tRNAs)...
  18. R

    AS Biology P1 MCQs Preparation Thread

    qn 10 - It cannot be solution 2 since the colour before adding acid and neutralising was orange and the colour did not shift towards red after hydrolysis with acid, which would have been the case, had the solution contained non-reducing sugars. The green colour after hydrolysis is due to the...
  19. R

    AS Biology P1 MCQs Preparation Thread

    Exactly! even if the answer is not exact, you should select the option closest to your calculated value. The concept behind the calculation is what really matters. :) It is quite useful in Physics Paper 1 and even in Bio now...
  20. R

    AS Biology P1 MCQs Preparation Thread

    If u guys see the examiner report of that particular paper: http://www.xtremepapers.com/papers/CIE/Cambridge%20International%20A%20and%20AS%20Level/Biology%20(9700)/9700_s06_er.pdf , you will see that question no.30 was withdrawn from the examination due to difficulties in reading the graph. The...
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