The document outlines

1. 1B Biology Exam format
• 30 Obj. q’tions (30m)
• 5 P2 Structure (Section A) (50m)
• 1 P2 Essay (Section B) (10m)
• 1 P3 Question 2 (10m)

2. P2 Section B
1 a) Extracellular enzymes are enzymes that are used
outside the cell they were synthesised. With the
help of a diagram, explain the synthesis of
extracellular enzymes. (10m)
b) You intend to set up a food processing factory with
meat and fish as the main ingredients. Suggest an
enzyme that can be used in this industry and state
your reasons. (4m)
c) Protein can be classified based on their structure.
Describe the four structures of protein. (6m)

3. Enzyme expelled
Rough
endoplasmic
reticulum
(5m)
Nucleus
Secretory
vesicle
Ribosomes
Transport
Protein vesicle
Golgi
apparatus

4. a)
Answers Marks
 Diagram + Label 5m
 Transcription of DNA into mRNA in nucleus 1m
 mRNA is then transported out from nucleus 1m
into ribosome to form protein via translation
process
 Protein is packed into transport vesicle and 1m
carried to Golgi apparatus
 In Golgi apparatus, protein is modified into 1m
enzymes
 Enzymes is packed into secretory vesicle which 1m
fuse with plasma membrane and enzyme is
released

5. P2 Section B
1 a) Extracellular enzymes are enzymes that are used
outside the cell they were synthesised. With the
help of a diagram, explain the synthesis of
extracellular enzymes. (10m)
b) You intend to set up a food processing factory with
meat and fish as the main ingredients. Suggest an
enzyme that can be used in this industry and state
your reasons. (4m)
c) Protein can be classified based on their structure.
Describe the four structures of protein. (6m)

6. b)
Answers Marks
 Enzyme protease 1m
 Protease can tenderise meat to make the meat 1m
taste better
 Protease can remove animal hair / fur before 1m
the meat is being processed
 Remove scales of fish 1m

7. P2 Section B
1 a) Extracellular enzymes are enzymes that are used
outside the cell they were synthesised. With the
help of a diagram, explain the synthesis of
extracellular enzymes. (10m)
b) You intend to set up a food processing factory with
meat and fish as the main ingredients. Suggest an
enzyme that can be used in this industry and state
your reasons. (4m)
c) Protein can be classified based on their structure.
Describe the four structures of protein. (6m)

8. c)
Answers Marks
 Can start by writing a short, precise 0m
introduction (eg: Protein can be divided into
primary, secondary, tertiary and quaternary
structure.)
 Primary structure:
 Straight chain of amino acid sequence / 1m
Straight chain of polypeptide chain
 Secondary structure:
 Polypeptide chain coiled and folded to form 1m
alpha-helix and beta-pleated respectively
 Formed by hydrogen bond 1m

9. Answers Marks
 Tertiary structure:
 Folded in various way to form globular 1m
protein
 Example are enzymes and hormones 1m
 Formed by hydrogen bond, ionic bond and 1m
disulphide bridges
 Quaternary structure:
 Formed by several polypeptide chains joined 1m
together
 Example is haemoglobin 1m
All the four structures must be mentioned
and explained!

10. P3 Question 2
a) The rate of enzyme reaction is influenced by the pH
value of the medium of reaction. Some enzymes are
most active in an acidic medium while some are more
active in an alkaline or neutral medium.
Based on this statement, design an experiment to
show the effect of pH values on the rate of pepsin
reaction. The planning of your experiment should
include:
 Problem statement (3m)
 Hypothesis (3m)
 Variables (3m)
 Materials and apparatus (3m)
 Procedure (3m)
 Presentation of data (2m) (17m)

11. Answers:
Aspect Criteria M
Problem  Able to state problem statement correctly.
statement  Manipulated variable
 Responding variable
 Question form & have relationship
 Without question mark, - score 2m
 Sample answer:
What is the pH value where enzyme pepsin is 3m
most active?
Variables  Able to state all 3 variables correctly.
 Sample answer:
 Manipulated: pH value of medium 3m
 Responding: Changes in albumen solution at
the end of experiment
 Constant: Temperature of medium, [E], [S]

12. Hypothesis  Able to relate manipulated & responding
variable correctly.
 State manipulated variable
 State responding variable
 Show specific relationship
 Sample answer:
Enzyme pepsin is most active in acidic 3m
medium / Enzyme pepsin is most active at
pH3
Materials  Able to list all the materials & apparatus
&
apparatus  Sample answer:
 Materials: 0.1M hydrochloric acid, 0.1M 3m
sodium hydroxide, distilled water, pepsin,
albumen
 Apparatus: Beaker, test tubes, Bunsen
burner, wire gauze, tripod stand,
thermometer, syringe

13. Procedure  Able to write all the steps and include
diagram
 In passive form
 Sample answer:
(Diagram) 3m
1. 4ml of albumen is poured into each of the test
tube, labeled A, B and C
2. Each test tube is added with the following
mixtures according to the table below.
(Table)
3. pH paper is used to determine the pH value
of each solution. The pH is recorded.
4. All the test tubes are placed in water bath
at 370C for 20 minutes.
5. Change in each test tubes is observed and
recorded.

14. Presentation  Able to draw a complete table to record
of data relevant data based on:
 Aspects with correct units
 Correct samples
 Sample answer:
2m
Test pH Observations after 20 minutes
tube
A 3
B 9
C 7

15. Homework (P2 Section B):
2. An experiment was conducted to study the effect of
temperature on enzyme reaction. The results of the
experiment are shown in table below.
Test tube Temperature (0C) Time (min.)
P 5 16
Q 28 4
R 37 2
S 45 6
T 60 20

16. a) Based on the table, draw a graph showing rate of
enzyme activities (1/time) against temperature. (4m)
b) Explain why high temperature can affect the function
of proteins (6m)
c) Describe how the characteristics of enzymes
influence their activity (10m)

17. Homework (P3 Question 2):
b) One of the factors affecting rate of enzyme reaction
is enzyme concentration. Amylase catalyses the
hydrolysis of starch in mouth. Plan a laboratory
experiment to study the relationship between
concentration of amylase on rate of reaction of
amylase. The planning of your experiment should
include:
 Problem statement
 Hypothesis
 Variables
 Materials and apparatus
 Procedure
 Presentation of data (17m)