Friday 24 May 2026- Morning AS Level
Biology A H020/02 Depth in biology
An investigation was carried out into the loss of water from a leafy shoot. The apparatus used is
shown in Fig. 4.1 - ANS-transpiration is equal to water uptake
\Cells A, C and D work together to carry out an important function. State the function that cells
A, C and D perform - ANS-immunity
\Fig. 2, on the insert, is a photomicrograph of a mammalian blood smear. (a) Calculate the
image length, in µm, represented by the scale bar. Give your answer to 2 significant figures -
ANS-14 or 15 or 16 ÷ 1250 x 1000= 12
\identify an anomalous reading in the data and evaluate the extent to which it has affected the
mean that has been calculated - ANS-57
Has increased the mean in trial 4 condition 3
(ignoring / excluding 57) mean = 29.4
\Name the cell labelled B - ANS-erythrocyte
\Phloem tissue is made up of different cell types. Identify the type of phloem cell into which the
stylet is inserted to obtain the sap - ANS-sieve tube element
\Separate samples of the sap were tested for the presence of glucose, starch and sucrose.
Using Table 1, complete the following passage, using the most appropriate terms
In order to test for the presence of glucose, ................................. ................................. was
added to the sap sample and boiled. The final colour was ....................................... and so it was
possible to arrive at the conclusion shown in Table 1. When iodine solution was added to the
sap sample, the final colour was ................................................... . To test for the presence of
sucrose, the sample was first boiled with ................................................... . After the rest of the
test had been completed, the colour of the mixture indicated that sucrose was present in the
sample - ANS-1. Benedicts solution
2. Blue
3. Brown
4. Acid
\Sucrose is carried in phloem sap from source to sink. (i) Explain why starch is not transported
in the sap - ANS-Because it is not soluble
\Suggest a reason for the reading that you identified as anomalous in - ANS-misread, scale /
ruler / distance
bubble was not (fully) returned to starting position
\Suggest why sucrose is a more suitable transport molecule than glucose - ANS-less likely to,
leave / exit / diffuse out of (sieve tubes
loading uses transport proteins
\The control experiment in this investigation was to measure the mean rate of transpiration in
still air. Explain why the control experiment is carried out in this investigation - ANS-to, see /
compare, effect of, other (named) treatment(s) / changed conditions
\The smear has been stained with haematoxylin and eosin stain. This is a differential stain.
Biology A H020/02 Depth in biology
An investigation was carried out into the loss of water from a leafy shoot. The apparatus used is
shown in Fig. 4.1 - ANS-transpiration is equal to water uptake
\Cells A, C and D work together to carry out an important function. State the function that cells
A, C and D perform - ANS-immunity
\Fig. 2, on the insert, is a photomicrograph of a mammalian blood smear. (a) Calculate the
image length, in µm, represented by the scale bar. Give your answer to 2 significant figures -
ANS-14 or 15 or 16 ÷ 1250 x 1000= 12
\identify an anomalous reading in the data and evaluate the extent to which it has affected the
mean that has been calculated - ANS-57
Has increased the mean in trial 4 condition 3
(ignoring / excluding 57) mean = 29.4
\Name the cell labelled B - ANS-erythrocyte
\Phloem tissue is made up of different cell types. Identify the type of phloem cell into which the
stylet is inserted to obtain the sap - ANS-sieve tube element
\Separate samples of the sap were tested for the presence of glucose, starch and sucrose.
Using Table 1, complete the following passage, using the most appropriate terms
In order to test for the presence of glucose, ................................. ................................. was
added to the sap sample and boiled. The final colour was ....................................... and so it was
possible to arrive at the conclusion shown in Table 1. When iodine solution was added to the
sap sample, the final colour was ................................................... . To test for the presence of
sucrose, the sample was first boiled with ................................................... . After the rest of the
test had been completed, the colour of the mixture indicated that sucrose was present in the
sample - ANS-1. Benedicts solution
2. Blue
3. Brown
4. Acid
\Sucrose is carried in phloem sap from source to sink. (i) Explain why starch is not transported
in the sap - ANS-Because it is not soluble
\Suggest a reason for the reading that you identified as anomalous in - ANS-misread, scale /
ruler / distance
bubble was not (fully) returned to starting position
\Suggest why sucrose is a more suitable transport molecule than glucose - ANS-less likely to,
leave / exit / diffuse out of (sieve tubes
loading uses transport proteins
\The control experiment in this investigation was to measure the mean rate of transpiration in
still air. Explain why the control experiment is carried out in this investigation - ANS-to, see /
compare, effect of, other (named) treatment(s) / changed conditions
\The smear has been stained with haematoxylin and eosin stain. This is a differential stain.
