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Published by rizkasturi, 2021-04-11 01:23:26


Chapter 22 – Immunity


1. A) FIGURE 4 shows immunological memory.

i) Explain briefly the production of antibody A in FIGURE 4. [3 marks]

When a person is exposed to an antigen for the first time, there is a lag of several days

before specific antibody becomes detectable.
This antibody is IgM.

After a short time, the antibody level declines.

ii) Why antibody A is higher than antibody B at day 28 – 42? [2 marks]

re-exposed to the same antigen,
there is a far more rapid appearance of antibody,

and in greater amount

Chapter 22 – Immunity

2. FIGURE 4 shows primary and secondary immune responses.

a) What is meant by ‘secondary response’? [1 mark]
The reaction of the immune system when it contacts an antigen for the second/ same

and subsequent times

b) Name the classes of antibodies at X, Y and Z. [3 marks]
X : IgM

Y : IgG
Z : IgM

c) Name the cell that is involve in [2 marks]
i) Primary response

T cell, B cell
ii) Secondary response

Memory (B) cell Memory Helper T cell

d) State TWO differences between primary and secondary responses. [2 marks]
The rate of response of the primary immune response is slower compared to the
secondary immune response// The rate of response of the secondary immune
response is faster / rapid compared to the primary immune response

The magnitude of response/concentration of antibody of the primary
immune response is smaller// The magnitude of response / concentration of
antibody of the secondary immune response is greater/ higher compared to the
primary immune response

Chapter 22 – Immunity

The effect of the primary immune response is short whilst the effect of the

secondary immune response is long lasting

A primary immune response is slow in onset and low in magnitude.
A secondary immune response is rapid in onset and high in magnitude

e) State TWO types of vaccination that commonly given in Malaysia. [2 marks]

Rubella, BCG, Hepatitis and triple antigen (any two)

3. A) FIGURE 3 shows active immune response in human.

i) How do humoral immune response and cell mediated immune response fight pathogens?
[4 marks]

Humoral immune : Involves antibodies produced by plasma cells derive from B

response lymphocytes in response to a specific antigen

Cell mediated immune : Due to the development of T Cells

response T lymphocytes which respond to intracellular antigens.

Chapter 22 – Immunity

a) Secondary immune response is more rapid and intense then the primary immune

response. Explain why. [3 marks]
During the primary immune response, in addition to differentiating into
antibody-secreting plasma cells,
B lymphocytes also differentiate to become memory cells which are long-lasting.
These memory cells trigger the production of antibodies at a faster rate and larger
amount when exposed to the same antigens again

4. FIGURE 3 shows a simplified process of humoral immune response.

a) Name cell M, N and O. [3 marks]

M : B cell
N : Memory B cell

O : Plasma cell

b) State the importance of cell N. [1 mark]

Descendant of B cell that remains after an immune response// respond during a
second infection of the same antigen

c) How does the helper T cell work to activate cell M? [1 mark]

By secreted Interleukin 2

Chapter 22 – Immunity

5. FIGURE 4 shows the role of helper T cell in two types of immune response.

a) Name immune response X and Y. [2 marks]

X : Humoral immune response
Y : Cell mediated immune response

b) What is molecule Z? [1 mark]


c) Name one class of molecule Z secreted by plasma cell when a person is exposed to a

pathogen for the first time. [1 mark]

d) State one type of interaction between Z and antigen. [1 mark]
Activation of complement system and pore formation (any one)

e) What will happen when activated cytotoxic T cell binds to infected cell? [3 marks]

The cytotoxic T cell releases perforin molecules which form pores in the infected cell
The cytotoxic T cell releases enzyme that break down the infected cell (granzymes)

Chapter 22 – Immunity

Destroy antigen-bearing (infected) cells// infected cell rupture and die
f) If a child was born without a thymus gland, how would it affect the immune response?
[2 marks]

T lymphocyte not mature
Cannot respond to intracellular antigens.

6. FIGURE 4 shows the immune responses after vaccination.

(a) Define the term immunity. [1 mark]

Resistance/protection to specific body invaders / pathogens / bacteria/viruses

(b) What type of immunity is shown in the graph above? [1 mark]

Artificial active immunity

(c) (i) What is A and B? [2 marks]
A : Primary immune response

B : Secondary immune response

(ii) Give TWO differences between A and B. [2 marks]

A primary immune response is slow in onset and low in magnitude.
A secondary immune response is rapid in onset and high in magnitude

Chapter 22 – Immunity

(d) Name the class of antibody represented by X and Y. [2 marks]

X : Immunoglobulin G/ IgG
Y : Immunoglobulin M/ IgM

(e) What is the difference between antigen and antibody? [2 marks]
Antigen is the trigger for immune response while antibody is the product of the


7. FIGURE 4 shows the antibody concentration in human after exposure to antigen A and
antigen B.


(a) What is meant by antibody and antigen? [2 marks]
Antigen is the trigger for immune response while antibody is the product of

the response

(b) State the level of development of immune response at P and Q. [2 marks]
P : high in magnitude.

Q : low in magnitude.

Chapter 22 – Immunity

(c) State TWO advantages of the antibodies characteristics produced at P compare to Q.
[2 marks]

The immune response to produce effector cells is shorter, due to the presence of memory
cells of B & T cells.
Antibody level tends to remain high for longer time.
Amount of antibody produced is higher
Main antibody produced is IgG (small amounts of IgM are produced).

(d) State the type of cell involved in the above immune response and the specific location
where it is produced. [4 marks]

B cell
Memory B cell
Plasma cell
Bone marrow

8. FIGURE 4 shows the summary of the formation of lymphocyte cells and their roles.

a) In which part of the human body do the cells achieve maturity?

B Lymphocyte: bone marrow
T Lymphocyte : thymus [2 marks]

Chapter 22 – Immunity

b) Name the types of immunity response shown in FIGURE 4.

Immune Reaction X: humoral immune response
Immune Reaction Y: cell mediated immune response [2 marks]

c) Give TWO examples of helper cell.

i) T 1/initiator cells/Helper T
ii) T 2/ stimulant cells/ Helper T memory [2 marks]

9. FIGURE 4 shows humoral response during immunity formation.

a) What is meant by antigen?
Foreign substances capable of stimulating an immune response

[1 mark]

b) What are P, Q, R and S in FIGURE 4?
P : Lymphocyte B

Q : Plasma cells
R : Antibodies

S : Memory B cell [4 marks]

c) What is the effect of an antigen action on P?
To stimulate proliferation of B cells and

Formation of antibody [2 marks]

Chapter 22 – Immunity

d) i) How does helper T cell stimulate P?

By releasing IL-2

ii) What is the function of helper T cell besides stimulating P?
Stimulate cytotoxic T cell become active killer cells [2 marks]

e) State the effect of S on immunity system.

Can respond rapidly when subsequently exposed to the same antigen. [1 mark]

10. FIGURE 4 shows an immune response.


B Cell



(a) State the types of this immune response.
Humoral immune response//Antibody- mediated response
[1 mark]
(b) What is S ?
Antigens (which originated from pathogen)//peptides fractions from
pathogen//peptides from bacteria
[1 mark]
(c) After receiving information from the macrophage, T cell will secrete U.
What is U and state its function.
U : cytokines//lymphokine//interleukin
Function : activates B cell
To divide /proliferate
[3 marks]
(d) What are cells P and Q ?
Cell P : Memory (B) cells
Cell Q : Plasma (B) cells

Chapter 22 – Immunity

[2 marks]
(e) State TWO mechanisms of actions of R.
Neutralization/Agglutination/Precipitation/Activation of complement system (to
increase phagocytosis)//To increase inflammation//lysis
[2 marks]

11. FIGURE 4 shows part of the mechanism of an immune response.

a) Name the cell labeled C, D, E, and F.

C: Helper T (cell) // Th cell // TH cell
D: Cytotoxic T (cell)

E: B (cell)

F: Memory (cell) // Memory β (cell)
[4 marks]
b) What is protein X? State its function.
Protein X: Interleukin-1 // IL-1

Function: Activates the helper T cell
[2 marks]
c) State the location where cell C matures
Thymus gland
[1 mark]
d) State the mechanism of action of cell D

Cell D / Cytotoxic T cell binds/touch to the infected cell and destroys / kills it.
[2 marks]

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