No questions found
(a) (i) Decide on the concentrations of $E$ you will use in your investigation.
You will need to make up to $10 \text{cm}^3$ of each $E$ concentration.
Prepare the space provided on page 3 to show:
▪ the concentrations of $E$
▪ the volumes of $E$
▪ the volumes of $W$.
(a) (ii) Prepare the space below and record your results.
(a) (iii) Describe how you would set up a control using the apparatus provided.
(a) (iv) Fig. 1.5 shows the ruler used by a student in step 6 to measure the depth of $E$.
State the degree of uncertainty of the measurements using this ruler.
(a) (v) Identify two significant sources of error in your investigation.
(a) (vi) Suggest how you would make two improvements to this investigation.
(b) (i) Plot a graph of the data shown in Table 1.1.
[Table_1.1]
(b) (ii) From your graph state the mass of product formed in a minute for immobilised lactase beads of 2 mm diameter.
(b) (iii) Explain the effect of immobilised lactase bead diameter on the mass of product formed in a minute, using the data and Fig. 1.6.
583
598
546
J1 is a slide of a stained transverse section through a mammalian lung.
(a) Make a large drawing to show the walls of two whole alveoli.
Label a nucleus.
Fig. 2.1 is a photomicrograph of a transverse section through an artery which shows the lumen partially blocked. A grid has been placed over the photomicrograph to help you answer (b)(i) and (ii).
Fig. 2.1
(b) (i) Describe how you will use the grid to find the total area of the lumen and the area of the lumen that is blocked.
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[1]
(ii) Calculate the percentage change in area of the lumen caused by the blockage.
You may lose marks if you do not show your working or if you do not use appropriate units.
....................% [4]
Fig. 2.2 and Fig. 2.3 are photomicrographs of red blood cells from a fish species and a frog species respectively.
Fig. 2.2 magnification \times 630 Fig. 2.3
(iii) Make a large drawing of two red blood cells from each species.
Label the cell membrane of one red blood cell.
Fish cells
Frog cells
[4]
(iv) Prepare the space below so that it is suitable for you to show the observable differences between the specimens in Fig. 2.2 and 2.3.
Record your observations in the space you have prepared.
[4]
593
586
562
