hkdse biology exercise vol1

HKDSE Biology Structured Questions

★ nature of science

FREE

Volume 1 July 2013

Desmond Wong

★ data interpretation

★ application of knowledge

★ scientific investigation

All rights reserved. blog.yahoo.com/onebio

HKDSE Biology Sample Question Page 1

Question 1

The micrographs below show part of a vertical section taken from a plant stem and the magnified

view of structure X. Both cell types P and Q are involved in transport.

(a) (i) Name cell type P and structure X. (2 marks)

(ii) With reference to one feature of structure X shown in the electron micrograph,

explain how it facilitates the function of cell type P. (2 marks)

(b) (i) Name an organelle that is present in cell type Q but absent in cell type P. (1 mark)

(ii) Explain the significance of the above difference to their functions. (2 marks)

(c) Transport of substances downward through cell type P is very important to roots. Explain why.

(3 marks)

a magnified view of X

P

Q

X

a vertical section from

a plant stem



Question 2

The following photographs show the fruits of two woodland trees, A and B.

(a) (i) State the method of dispersal for the above fruits.

Support your answer with one observable feature from the above photographs. (2 marks)

(ii) Explain the significance of fruit dispersal to a plant. (1 mark)

(b) A student has taken a study of the distribution of fruits around tree A.

His findings are shown in the table below:

Direction

Distance from the tree trunk of A (m)

0 5 10 15 20 25

North (N) 5 3 3 0 2 0

South (S) 5 9 11 7 4 4

East (E) 9 14 21 26 19 10

West (W) 2 2 1 1 1 0

(i) Briefly describe how the student obtained the above data by using some devices for

ecological study. (4 marks)

(ii) In which direction were

(1) most fruits dispersed;

(2) least fruits dispersed? (2 marks)

Suggest a reason for the unequal distribution of fruits around tree A. (2 marks)

(iii) (1) Plot a graph to show how the number of fruits, on the east-facing side of tree A,

varied with distance from the trunk. (3 marks)

(2) Explain the trend of fruit dispersal as the distance from tree trunk increases from

0m to 15m, as shown in the graph plotted in (1). (4 marks)

Photograph 1: fruits of tree A Photograph 2: fruits of tree B



(c) (i) After examining their external features, the student hypothesized that the fruits of tree B

fall more slowly than fruits of tree A. Based on the above photographs and assuming that

both types of fruits bear the same weight, suggest how the student comes to this

hypothesis. (1 mark)

(ii) Design an experiment for him to test this hypothesis. (2 marks)



Question 3

It is often said that cooking destroys vitamin C. A student tested this notion by doing the following

experiment:

A blue agar plate containing DCPIP was prepared and four wells were bored in this plate. Fresh

lemon juice and fresh orange juice were added into wells 1 and 2 respectively while boiled lemon

juice and boiled orange juice were added into wells 3 and 4 respectively after cooling.

After an hour, a clear zone was formed around each well and its area was measured. The results are

recorded in the table below:

Well number Content Area of clear zone (cm2)

1 Fresh lemon juice 1.42

2 Fresh orange juice 2.36

3 Boiled lemon juice 1.40

4 Boiled orange juice 2.37

(a) Explain why a clear zone is formed around the well. (2 marks)

(b) (i) State the dependent variable in this experiment. (1 mark)

(ii) State two variables that needed to be kept constant in this experiment. (2 marks)

(c) With reference to the results in wells 1 and 2, what conclusion can be drawn? (1 mark)

(d) Explain why it is necessary to cool down the boiled fruit juices before adding into the wells.

(1 mark)

(e) Is the notion "cooking destroys vitamin C” supported by the results of this experiment?

Justify your answer with reference to the results obtained in this experiment. (3 marks)

after 1 hour

agar plate containing DCPIP

2 1

3 4

clear zone



Question 4:

Read the paragraph below and answer the questions that follow.

(a) Write a word equation to show how lactose is digested by lactase. (2 marks)

(b) Based on your biological knowledge, explain why people with lactose intolerance often have

diarrhea after they consume milk products. (4 marks)

(c) A person received a diagnostic test for lactose intolerance. He was first fed with lactose and

then his blood glucose level was measured to monitor any changes.

Sketch two curves on the graph below to show how the blood glucose levels change,

(i) if he has lactose intolerance; and

(ii) if he does not have lactose intolerance. (3 marks)

Lactose Intolerance

Lactose is a sugar that is naturally present in milk. It can be digested by the enzyme

lactase, which is adequately secreted in newborn babies. However, in some adult

humans, levels of lactase decline and become too low to digest lactose adequately.

As a result, lactose passes through the alimentary canal undigested, causing cramps and

diarrhea. This condition is known as lactose intolerance.

Time (minutes)

Blo

od

gluco

se level

(arbitrary u

nit)

Intake of lactose



(d) A student wants to build up the size of his muscles by working out at the gym. In order to get

the desired results quickly, his personal trainer advises him to drink milk every day, in

additional to doing weight bearing exercise.

(i) Explain why drinking milk helps build up muscle. (2 marks)

(ii) As the student suffers from lactose intolerance, he feels uncomfortable after consuming

milk. What drink will you recommend to him instead? (1 mark)

(e) Whether lactose intolerance should be regarded as "abnormal" is still under debate.

From a dietary point of view, argue why it can also be considered as "normal" in human.

(3 marks)



Question 5:

In 1855, a French scientist named Claude Bernard conducted a series of experiments to study the role

of liver in glucose metabolism.

Below is the outline of his design and the results:

Experimental conditions Results

Treatment 1 a fasting dog with its liver intact blood glucose level remained normal

Treatment 2 a fasting dog with its liver removed blood glucose level fell rapidly

Treatment 3 a fasting dog with its liver intact;

blood sample was taken from its

hepatic vein and hepatic portal vein

blood glucose level in hepatic vein

was higher than that in hepatic portal

vein

Treatment 4 (a) A liver was removed from a dog, which

had been fed normally for a few days.

It was then washed with cold water

through the portal vein and the blood

came out through the hepatic vein.

The liver was washed in this way

continuously for 40 minutes.

at the beginning, both the liver

and the emerging blood

contained glucose;

at the end of the washing, both

the liver and the emerging blood

did not contain glucose

Treatment 4 (b) The sugar-free liver from 4 (a) was left

in a closed jar for 24 hours;

then its glucose level was measured

again

a high level of glucose was found in

the liver

(a) Based on the results of treatment 1 and 2, what conclusion can you draw? (1 mark)

(b) Based on present day knowledge of glucose metabolism, explain the result of treatment 3.

(4 marks)

(c) In Bernard's time, people believed that the liver caused the formation of glucose directly in

the blood passing through it. Is this belief supported by the results of this experiment?

Explain your answer. (2 marks)

(d) To account for the result in treatment 4 (b), someone hypothesized that an enzyme's action may

be involved

(i) Suggest what further experiment can be done in order to prove his hypothesis. (1 mark)

(ii) What is the expected result if this hypothesis is correct? (1 mark)

hkdse biology exercise vol1

Documents