BIO_Ch02_SQ_e.doc - HKDSE BIOLOGY: Connecting Concepts...

HKDSE BIOLOGY: Connecting Concepts Chapter 2
Question bank Short questions
Short questions
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The diagram below shows the molecular structure of a part of a DNA molecule.
(a) Identify the components X, Y and Z. (3 marks)
(b) Name the basic units which make up a DNA molecule. (1 mark)
(c) What are the bonds labelled A? How is this type of bond important to DNA
molecules? (2 marks)
##
Y
Y
X
X
Z
A
guanine
________
(6 marks)
##
Skills assessed Marks
(a) Analysing data 3
(b) Understanding basic concepts 1
(c) Understanding basic concepts 2
© 2019 Aristo Educational Press Ltd. 1

HKDSE BIOLOGY: Connecting Concepts Chapter 2
Question bank Short questions
|!|BCESB0020000002|!|
 SI
The set-up below was used to find the energy content of three food samples (A, B and
C). One gram of food sample was burned and the energy released heated the water in the
test tube. The starting temperatures and the highest temperatures of the water were
measured.
(a) State two variables that have to be kept constant during the investigation. (2 marks)
The table below shows the results.
Food
sample
Water temperature (
o
C)
Rise in
temperature
( o C)
Energy
content
(kJ per g)
Starting Highest
A 25 34 9 7.56
B 24 40 16 13.44
C 22 33
The energy content of the food (kJ per g) can be calculated using the formula:
Energy content = volume of water (cm
3
) × temperature rise × 0.042
© 2019 Aristo Educational Press Ltd.
thermometer
test tube containing
20 cm 3 of water
1 g of food
sample burning
2

HKDSE BIOLOGY: Connecting Concepts Chapter 2
Question bank Short questions
(b) Complete the table to show the rise in temperature and energy content of sample C.
(2 marks)
(c) The three samples are peanut oil, rice and egg white. It is known that sample A is
egg white. Based on the results, deduce which sample is peanut oil. (2 marks)
(d) Which element is always found in proteins but not in lipids or carbohydrates?
(1 mark)
##
(a) volume of water in the test tube / mass of food used / distance between the burning
food and the test tube / other reasonable answer (Any two , 2)
(b) Rise in temperature: 11
o
C (1)
Energy content: 9.24 kJ per g (1)
(c) Sample B is peanut oil. (1)
The energy content of lipids is higher than / is roughly twice that of proteins. (1)
(d) nitrogen (1)
________
(7 marks)
##
Skills assessed Marks
(a) Practical skills 2
(b) Mathematical skills 2
(c) Analysing data 2
(d) Understanding basic concepts 1
© 2019 Aristo Educational Press Ltd. 3

HKDSE BIOLOGY: Connecting Concepts Chapter 2
Question bank Short questions
|!|BCESB0020000003|!|
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